Handbook of Nanomaterials in Analytical Chemistry: Modern Trends in Analysis 0128166991, 9780128166994

Table of contents :
Cover
Handbook of Nanomaterials in Analytical Chemistry: Modern Trends in Analysis
Copyright
Contents
List of contributors
Section I: Modern age of analytical chemistry—Nanomaterials (NMs)
1 Carbon nanodots from natural (re)sources: a new perspective on analytical chemistry
1.1 Introduction
1.2 Synthesis of carbon nanodots
1.2.1 Solvothermal carbonization
1.2.2 Pyrolysis
1.2.3 Microwave treatment
1.3 Characteristics of carbon nanodots
1.3.1 Structural characteristics
1.3.1.1 Nondoped carbon nanodots
1.3.1.2 N-doped carbon nanodotss
1.3.1.3 N,S-(co)doping
1.3.2 Spectral properties and chemical stability of carbon nanodots
1.3.2.1 Ultraviolet absorption
1.3.2.2 Photoluminescent properties
1.3.2.2.1 Downconversion
1.3.2.2.2 Upconversion
1.3.2.3 Photoluminescence stability
1.4 Analytical applications of carbon nanodots fluorescence systems
1.4.1 Cations—metal ions
1.4.1.1 Ferric ions
1.4.1.2 Mercury ions
1.4.1.3 Copper ions
1.4.1.4 Other (heavy) metal ions
1.4.2 Organic molecules
1.4.2.1 Analytical systems for food components
1.4.2.2 Probes for analytes of environmental importance
1.4.2.3 Probing analytes of biological importance
1.4.3 “Off–On” CND-based PL systems
1.5 Mechanisms of CND-based photoluminescent analytical systems
1.5.1 Static quenching
1.5.2 Dynamic quenching
1.5.3 Inner filter effect
1.5.4 Förster resonance energy transfer
1.6 Conclusions
References
2 Modern age of analytical chemistry: nanomaterials
2.1 Introduction
2.2 History of analytical chemistry
2.3 History of nanotechnology
2.4 Classification of nanomaterials and application of nanomaterials as tools and analytes
2.5 Conclusions
References
Section II: Nanomaterials (NMs) in sample preparation
3 Nanomaterials for microextraction techniques in bioanalysis
3.1 Introduction
3.2 Nanomaterials classifications
3.2.1 Metallic/metallic oxide nanoparticles
3.2.2 Silicon oxide nanoparticles
3.2.3 Magnetic nanoparticles
3.2.4 Polymer nanoparticles
3.2.4.1 Organic nanomaterials
3.2.4.2 Inorganic and mixed polymers
3.2.4.3 Selective nanomaterials
3.2.5 Carbon-based nanomaterials
3.3 Nanomaterials application in microextraction methods
3.4 Recent nanomaterials applications in microextraction techniques
3.4.1 In-tube solid-phase microextraction
3.4.2 Dispersive solid-phase microextraction
3.4.3 Supramolecular solvent microextraction
3.4.4 Microextraction by packed syringe
3.4.5 Stir bar sorptive extraction
3.4.6 Nanofibers as sorbent in microextraction techniques
3.4.7 Molecularly imprinted polymer nanomaterials in microextraction techniques
3.5 Concluding remarks
References
4 Recent advances in solid-phase extraction techniques with nanomaterials
4.1 Introduction
4.2 The application of nanomaterials in sample preparation
4.2.1 Solid-phase extraction
4.2.2 Solid-phase microextraction
4.2.3 Stir-bar sorptive extraction
4.2.4 Matrix solid-phase dispersion
4.3 Conclusion
Acknowledgment
References
5 The use of magnetic nanoparticles in sample preparation devices and tools
5.1 Introduction
5.2 Synthesis of magnetic nanoparticles
5.2.1 Thermal decomposition technique
5.2.2 Coprecipitation technique
5.2.3 Sol–gel synthesis
5.2.4 Hydrothermal synthesis
5.2.5 Microemulsion-based synthesis
5.2.6 Flow injection synthesis
5.2.7 Aerosol/vapor-phase-based synthesis
5.3 Solid-phase extraction
5.4 Magnetic solid-phase extraction
5.4.1 Magnetic solid-phase extraction for environmental samples
5.4.2 Magnetic solid-phase extraction for food and beverage samples
5.4.3 Magnetic solid-phase extraction for biological samples
5.5 Conclusion and future trends
References
Section III: Nanomaterials (NMs) in separation
6 Separation techniques with nanomaterials
6.1 Introduction
6.2 Nanomaterials in separation techniques
6.2.1 Carbon nanostructures
6.2.1.1 Fullerenes
6.2.1.2 Carbon nanotubes
6.2.1.3 Nanodiamonds
6.2.1.4 Graphene and graphene oxide
6.2.2 Organic polymer–based nanomaterials
6.2.3 Inorganic silica nanoparticles
6.2.4 Metallic nanoparticles
6.2.5 Metal oxide nanoparticles
6.2.6 Metal–organic frameworks
6.2.7 Magnetic nanoparticles
6.3 Separation techniques with nanomaterials
6.3.1 Membrane-based separation
6.3.2 Solid-phase extraction technique
6.3.2.1 Conventional solid-phase extraction
6.3.2.2 Dispersive solid-phase extraction
6.3.2.3 Solid-phase microextraction
6.3.3 Capillary electrophoresis
6.3.4 Chromatography
6.3.4.1 Liquid chromatography
6.3.4.2 Gas chromatography
6.3.5 Microfluidics
6.4 Potential applications of nanomaterial-based separation techniques
6.4.1 Isolation of specific target cells from a population
6.4.2 Nucleic acid separation
6.4.3 Protein and peptide separation
6.4.4 Application in metabolite separation
6.4.5 Application in material science
6.5 Conclusions and future prospects
References
Further reading
7 Membrane applications of nanomaterials
7.1 Introduction
7.2 Traditional membranes
7.3 Carbon nanomaterial-based membranes
7.3.1 Graphene-based membranes
7.3.2 Carbon nanotubes-based membranes
7.3.3 Fullerene-based membranes
7.4 Nanoparticle-based membranes
7.5 Molecularly imprinted polymer-based membranes
7.6 Conclusions and future trends
References
Section IV: Nanomaterials (NMs) in Integration (micro-TAS & Lab on Chip Analytical chemistry with Nanomaterials (NMs)
8 Micro total analysis systems with nanomaterials
8.1 Introduction
8.2 The components of micro total analysis systems
8.3 Advantages and disadvantages of micro total analysis systems
8.4 Applications of micro total analysis systems
8.4.1 Analysis of environmental samples
8.4.2 Analysis of food samples
8.5 Conclusions
References
Section V: Nanomaterials (NMs) in detection
9 Electrochemically engineered nanoporous photonic crystal structures for optical sensing and biosensing
9.1 Introduction
9.2 Fabrication and properties: nanoporous anodic alumina as effective medium
9.2.1 Fabrication of nanoporous anodic alumina
9.2.2 Structural engineering of nanoporous anodic alumina
9.3 Nanoporous anodic alumina photonic crystals as optical sensing platforms
9.3.1 Nanoporous anodic alumina distributed Bragg reflectors
9.3.2 Nanoporous anodic alumina gradient-index filters
9.3.3 Nanoporous anodic alumina optical microcavities
9.3.4 Other nanoporous anodic alumina photonic crystals sensing platforms
9.4 Conclusions
References
Further reading
10 Pressure and temperature optical sensors: luminescence of lanthanide-doped nanomaterials for contactless nanomanometry a...
10.1 Introduction
10.2 Temperature measurements—general remarks
10.3 Remote, contactless temperature sensing
10.4 Nanothermometry
10.4.1 Single-band intensity and double-band ratio nanothermometers
10.4.1.1 Pr3+
10.4.1.2 Nd3+
10.4.1.3 Sm3+
10.4.1.4 Eu3+
10.4.1.5 Gd3+
10.4.1.6 Dy3+
10.4.1.7 Ho3+
10.4.1.8 Er3+
10.4.1.9 Tm3+
10.4.1.10 Tb3+ and Yb3+
10.4.2 Dual and multicenter nanothermometers
10.4.3 Nanothermometers based on the band shift
10.4.4 Nanothermometers based on the bandwidth
10.4.5 Lifetime nanothermometers
10.4.6 Nanoheaters
10.5 High-pressure measurements—general remarks
10.5.1 Pressure chamber
10.5.2 Pressure-transmitting medium
10.6 High-pressure luminescence measurements
10.6.1 Diamonds
10.6.2 Source of excitation light
10.6.3 Detection geometry
10.6.4 Pressure determination—optical sensors
10.7 Optical nanosensors of pressure—nanomanometry
10.8 Concluding remarks
References
11 Nanoparticle-integrated electrochemical devices for identification of mycotoxins
11.1 Introduction
11.2 Surface modification of electrodes for electrochemical sensing of mycotoxins
11.2.1 Modification of electrodes with carbon nanomaterials
11.2.2 Modification of electrodes with metal nanoparticles
11.2.2.1 Modification of electrodes based on adsorption mechanism
11.2.2.2 Molecular assembly on metal and metal oxide nanoparticle surfaces
11.3 Summary
Acknowledgments
References
Further reading
12 Functional nanomaterial-derived electrochemical sensor and biosensor platforms for biomedical applications
12.1 Introduction
12.2 Noble metallic nanoparticles
12.2.1 Gold nanoparticles
12.2.2 Silver nanoparticles
12.2.3 Platinum nanoparticles
12.2.4 Palladium nanoparticles
12.3 Metal oxide nanomaterials
12.3.1 Cerium oxide nanomaterials
12.3.2 Copper oxide nanomaterials
12.3.3 Magnetic nanomaterials
12.4 Carbon nanomaterials
12.4.1 Carbon nanotubes
12.4.2 Graphene
12.5 Polymer nanomaterials
12.5.1 Dendrimers
12.5.2 Conducting polymers
12.5.3 Molecularly imprinted polymers
12.6 Bionanomaterials
12.6.1 Aptamers
12.6.2 DNA nanostructures
12.7 Conclusion
Acknowledgments
References
13 Nanomaterial-based sensors
13.1 Introduction
13.2 Graphene
13.2.1 Electrochemical graphene-based (bio)sensors
13.2.2 Optical graphene-based biosensors
13.3 Carbon nanotubes
13.3.1 Electrochemical carbon nanotube-based (bio)sensors
13.3.2 Optical carbon nanotube-based (bio)sensors
13.4 Other carbon-based materials
13.4.1 Other carbon-based materials in electrochemical biosensors
13.4.2 Other carbon-based materials in optical biosensors
13.5 Non-carbonaceous nanomaterials
13.5.1 Non-carbonaceous nanomaterials electrochemical (bio)sensors
13.5.1.1 AuNPs
13.5.1.2 AgNPs
13.5.1.3 Cu nanoparticles and Pt nanoparticles
13.5.1.4 Inorganic nanoparticles
13.5.2 Noncarbonaceous nanomaterials optical (bio)sensors
13.5.2.1 AuNPs
13.5.2.2 AgNPs
13.5.2.3 CuNPs and PtNPs
13.5.2.4 Inorganic nanoparticles
13.6 Nano/micromotors
13.7 Conclusions
Acknowledgments
References
14 MXene-based sensors and biosensors: next-generation detection platforms
14.1 Introduction
14.2 MXene-based sensing and biosensing for various analytes
14.2.1 MXenes for detection of biomolecules
14.2.2 MXene for detection of environmental contaminants
14.2.3 MXene for detection of gaseous molecules
14.2.4 MXene for detection of motion and physical stimuli
14.2.5 MXene for terahertz sensing
14.3 Conclusion
References
Section VI: Functionalized nanomaterials for analytical chemistry
15 Functionalized nanomaterials for sample preparation methods
Abbreviations
15.1 Introduction
15.2 Functionalized nanomaterials for sample preparation methods
15.2.1 Carbon-based nanomaterials
15.2.1.1 Functionalization of carbon-based nanomaterials
15.2.1.1.1 Covalent functionalization of carbon-based nanomaterials
15.2.1.1.2 Noncovalent functionalization of carbon-based nanomaterials
15.2.2 Metallic and metal-oxide nanomaterials
15.2.2.1 Functionalization of the metallic and metal-oxide nanomaterials
15.2.2.1.1 Chemical functionalization of the surface of the metallic and metal-oxide nanomaterials
15.2.2.1.1.1 Silanization
15.2.2.1.1.2 Sol–gel method
15.2.2.1.1.3 Bifunctional compounds
15.2.2.1.2 Functionalization of the surface of the metallic and metal-oxide nanomaterials via interactions
15.2.2.1.3 Functionalization of the surface of the metallic and metal-oxide nanomaterials via in situ chemical oxidation
15.2.2.1.4 Functionalization of the surface of the metallic and metal-oxide nanomaterials via solvothermal synthesis
15.2.2.1.5 Functionalization of the surface of the metallic and metal-oxide nanomaterials via liquid-phase deposition
15.2.2.1.6 Functionalization of the surface of the metallic and metal-oxide nanomaterials via electroless and electrochemic...
15.2.2.1.7 Functionalization of the surface of the metallic and metal-oxide nanomaterials via potentiostatic anodization
15.2.3 Magnetic nanomaterials
15.3 Conclusion
References
Further reading
16 Surface-modified metal nanoparticles for recognition of toxic organic molecules
16.1 Introduction
16.2 Colorimetric recognition of pesticides by surface-modified Ag nanoparticles
16.3 Colorimetric recognition of pesticides by surface-modified Au nanoparticles
16.4 Summary
Acknowledgment
References
Section VII: Nanomaterials: risk, toxicity, and regulatory norms
17 Safety risk, ELSI (ethical, legal, social issues), and economics of nanomaterials
17.1 Introduction
17.2 Nanomaterials and environment
17.3 Economics, modern policy, and legalization of nanotechnology
17.4 Conclusion and future trends
References
Further reading
Section VIII: Analysis of Nanomaterials
18 Advanced micro- and nanoscale characterization techniques for carbonaceous aerosols
18.1 Introduction
18.1.1 Carbonaceous aerosol and their source
18.1.2 Importance of nanoscale characterization
18.2 Analytical characterization techniques
18.2.1 Microscopic techniques
18.2.1.1 Scanning electron microscopy with energy-dispersive X-ray spectroscopy
18.2.1.2 Transmission electron microscopy with energy-dispersive X-ray spectroscopy
18.2.1.3 Atomic force microscopy
18.2.2 Spectroscopy techniques
18.2.2.1 Raman spectroscopy
18.2.2.2 Fourier-transforms infrared spectroscopy
18.2.2.3 X-ray photoelectron spectroscopy
18.2.2.4 Time-of-flight secondary ion mass spectrometry
18.2.2.5 Cavity ringdown spectroscopy
18.2.2.6 Single Particle Soot Photometer
18.3 Summary
References
19 Issues related with the analysis of nanomaterials
Abbreviations
19.1 Introduction
19.2 Nanomaterial characteristics: identifying key attributes
19.3 Analyzing nanomaterial physical attributes with automated and standardized methods
19.3.1 Standardization of methods for the analysis of nanomaterials
19.3.2 Analyzing the size of nanomaterials
19.3.3 Analyzing zeta potential of nanomaterials
19.4 Analyzing attributes of nanomaterials using other methods
19.4.1 Evaluating the shape of nanomaterials
19.4.2 Evaluating the porosity and crystallinity with general methods for the characterization of materials
19.4.3 Analysis of the intimate structure of nanomaterials
19.4.4 Thorough analysis of nanomaterial surface attributes
19.5 Conclusion
References
Further reading
Section IX: Future of analytical chemistry with nanomaterials
20 Graphene quantum dots in biomedical applications: recent advances and future challenges
20.1 Synthetic considerations
20.1.1 Preparation and physicochemical properties of graphene quantum dots
20.2 Biomedical applications of graphene quantum dots
20.2.1 Graphene quantum dots for in vitro biomarkers detection
20.2.1.1 Graphene quantum dot–based immunological assay
20.2.1.2 Graphene quantum dot–based nucleic acid assay
20.2.2 Graphene quantum dots for in vivo imaging
20.2.3 Graphene quantum dot–based platforms for drug delivery
20.3 Toxicity research of graphene quantum dot materials
20.4 Conclusion and perspectives
References
Index
Back Cover

Citation preview

Handbook of Nanomaterials in Analytical Chemistry

Handbook of Nanomaterials in Analytical Chemistry Modern Trends in Analysis

Edited by

Chaudhery Mustansar Hussain Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, NJ, United States

Elsevier Radarweg 29, PO Box 211, 1000 AE Amsterdam, Netherlands The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, United Kingdom 50 Hampshire Street, 5th Floor, Cambridge, MA 02139, United States Copyright © 2020 Elsevier Inc. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek permission, further information about the Publisher’s permissions policies and our arrangements with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/ permissions. This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein). Notices Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary. Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein. In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility. To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any liability for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein. British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloging-in-Publication Data A catalog record for this book is available from the Library of Congress ISBN: 978-0-12-816699-4 For Information on all Elsevier publications visit our website at https://www.elsevier.com/books-and-journals

Publisher: Susan Dennis Acquisition Editor: Kathryn Eryilmaz Editorial Project Manager: Redding Morse Production Project Manager: Swapna Srinivasan Cover Designer: Christian J. Bilbow Typeset by MPS Limited, Chennai, India

Contents

List of contributors

xi

Section I Modern age of analytical chemistry—Nanomaterials (NMs)

1

1

2

Carbon nanodots from natural (re)sources: a new perspective on analytical chemistry Th.G. Chatzimitakos and C.D. Stalikas 1.1 Introduction 1.2 Synthesis of carbon nanodots 1.3 Characteristics of carbon nanodots 1.4 Analytical applications of carbon nanodots fluorescence systems 1.5 Mechanisms of CND-based photoluminescent analytical systems 1.6 Conclusions References Modern age of analytical chemistry: nanomaterials Sibel Bu¨yu¨ktiryaki, Ru¨stem Kec¸ili and Chaudhery Mustansar Hussain 2.1 Introduction 2.2 History of analytical chemistry 2.3 History of nanotechnology 2.4 Classification of nanomaterials and application of nanomaterials as tools and analytes 2.5 Conclusions References

Section II 3

Nanomaterials (NMs) in sample preparation

Nanomaterials for microextraction techniques in bioanalysis Mohammad Mahdi Moein, Abbi Abdel-Rehim and Mohamed Abdel-Rehim 3.1 Introduction 3.2 Nanomaterials classifications 3.3 Nanomaterials application in microextraction methods 3.4 Recent nanomaterials applications in microextraction techniques

3 3 4 8 13 20 21 22 29 29 30 32 32 36 37

41 43

43 44 46 46

vi

Contents

3.5 Concluding remarks References 4

5

Recent advances in solid-phase extraction techniques with nanomaterials Yingying Wen 4.1 Introduction 4.2 The application of nanomaterials in sample preparation 4.3 Conclusion Acknowledgment References The use of magnetic nanoparticles in sample preparation devices and tools ˙ Ru¨stem Kec¸ili, Sibel Bu¨yu¨ktiryaki, Ibrahim Dolak and Chaudhery Mustansar Hussain 5.1 Introduction 5.2 Synthesis of magnetic nanoparticles 5.3 Solid-phase extraction 5.4 Magnetic solid-phase extraction 5.5 Conclusion and future trends References

Section III 6

7

52 52

57 57 58 66 67 67

75

75 76 79 79 89 90

Nanomaterials (NMs) in separation

97

Separation techniques with nanomaterials Prasad Minakshi, Mayukh Ghosh, Basanti Brar, Koushlesh Ranjan, Harshad Sudhir Patki and Rajesh Kumar 6.1 Introduction 6.2 Nanomaterials in separation techniques 6.3 Separation techniques with nanomaterials 6.4 Potential applications of nanomaterial-based separation techniques 6.5 Conclusions and future prospects References Further reading

99

Membrane applications of nanomaterials Ru¨stem Kec¸ili, Sibel Bu¨yu¨ktiryaki and Chaudhery Mustansar Hussain 7.1 Introduction 7.2 Traditional membranes 7.3 Carbon nanomaterial-based membranes 7.4 Nanoparticle-based membranes 7.5 Molecularly imprinted polymer-based membranes

99 101 108 136 139 139 158 159 159 159 160 167 169

Contents

vii

7.6 Conclusions and future trends References

175 176

Section IV Nanomaterials (NMs) in Integration (micro-TAS & Lab on Chip Analytical chemistry with Nanomaterials (NMs)

183

8

185

Micro total analysis systems with nanomaterials Ru¨stem Kec¸ili, Sibel Bu¨yu¨ktiryaki and Chaudhery Mustansar Hussain 8.1 Introduction 8.2 The components of micro total analysis systems 8.3 Advantages and disadvantages of micro total analysis systems 8.4 Applications of micro total analysis systems 8.5 Conclusions References

Section V 9

10

Nanomaterials (NMs) in detection

Electrochemically engineered nanoporous photonic crystal structures for optical sensing and biosensing Cheryl Suwen Law, Lluı´s F. Marsal and Abel Santos 9.1 Introduction 9.2 Fabrication and properties: nanoporous anodic alumina as effective medium 9.3 Nanoporous anodic alumina photonic crystals as optical sensing platforms 9.4 Conclusions References Further reading Pressure and temperature optical sensors: luminescence of lanthanide-doped nanomaterials for contactless nanomanometry and nanothermometry Marcin Runowski 10.1 Introduction 10.2 Temperature measurements—general remarks 10.3 Remote, contactless temperature sensing 10.4 Nanothermometry 10.5 High-pressure measurements—general remarks 10.6 High-pressure luminescence measurements 10.7 Optical nanosensors of pressure—nanomanometry 10.8 Concluding remarks References

185 186 188 188 195 195

199 201 201 203 207 219 220 226

227 227 229 231 234 253 254 258 263 265

viii

11

12

13

14

Contents

Nanoparticle-integrated electrochemical devices for identification of mycotoxins Suresh Kumar Kailasa, Tae Jung Park, Rakesh Kumar Singhal and Hirakendu Basu 11.1 Introduction 11.2 Surface modification of electrodes for electrochemical sensing of mycotoxins 11.3 Summary Acknowledgments References Further reading Functional nanomaterial-derived electrochemical sensor and biosensor platforms for biomedical applications Govindhan Maduraiveeran and Wei Jin 12.1 Introduction 12.2 Noble metallic nanoparticles 12.3 Metal oxide nanomaterials 12.4 Carbon nanomaterials 12.5 Polymer nanomaterials 12.6 Bionanomaterials 12.7 Conclusion Acknowledgments References Nanomaterial-based sensors Fabiana Arduini, Stefano Cinti, Viviana Scognamiglio and Danila Moscone 13.1 Introduction 13.2 Graphene 13.3 Carbon nanotubes 13.4 Other carbon-based materials 13.5 Non-carbonaceous nanomaterials 13.6 Nano/micromotors 13.7 Conclusions Acknowledgments References MXene-based sensors and biosensors: next-generation detection platforms Ankita Sinha, Dhanjai, Samuel M. Mugo, Jiping Chen and Koodlur S. Lokesh 14.1 Introduction 14.2 MXene-based sensing and biosensing for various analytes 14.3 Conclusion References

275

275 276 288 291 291 296

297 297 299 304 306 313 317 319 320 320 329

329 331 335 339 342 352 354 354 355

361

361 363 370 370

Contents

Section VI chemistry 15

16

ix

Functionalized nanomaterials for analytical 373

Functionalized nanomaterials for sample preparation methods Erkan Yilmaz and Mustafa Soylak Abbreviations 15.1 Introduction 15.2 Functionalized nanomaterials for sample preparation methods 15.3 Conclusion References Further reading Surface-modified metal nanoparticles for recognition of toxic organic molecules Suresh Kumar Kailasa, Rakesh Kumar Singhal, Hirakendu Basu and Tae Jung Park 16.1 Introduction 16.2 Colorimetric recognition of pesticides by surface-modified Ag nanoparticles 16.3 Colorimetric recognition of pesticides by surface-modified Au nanoparticles 16.4 Summary Acknowledgment References

Section VII Nanomaterials: risk, toxicity, and regulatory norms 17

Safety risk, ELSI (ethical, legal, social issues), and economics of nanomaterials Gustavo Marques da Costa and Chaudhery Mustansar Hussain 17.1 Introduction 17.2 Nanomaterials and environment 17.3 Economics, modern policy, and legalization of nanotechnology 17.4 Conclusion and future trends References Further reading

Section VIII 18

Analysis of Nanomaterials

Advanced micro- and nanoscale characterization techniques for carbonaceous aerosols Shahadev Rabha and Binoy K. Saikia 18.1 Introduction

375 375 376 379 402 402 413

415

415 416 420 429 429 429

433 435 435 437 441 442 444 446

447 449 449

x

19

Contents

18.2 Analytical characterization techniques 18.3 Summary References

451 465 465

Issues related with the analysis of nanomaterials Christine Vauthier Abbreviations 19.1 Introduction 19.2 Nanomaterial characteristics: identifying key attributes 19.3 Analyzing nanomaterial physical attributes with automated and standardized methods 19.4 Analyzing attributes of nanomaterials using other methods 19.5 Conclusion References Further reading

473

Section IX Future of analytical chemistry with nanomaterials 20

Graphene quantum dots in biomedical applications: recent advances and future challenges Xianxian Zhao, Weiyin Gao, Hong Zhang, Xiaopei Qiu and Yang Luo 20.1 Synthetic considerations 20.2 Biomedical applications of graphene quantum dots 20.3 Toxicity research of graphene quantum dot materials 20.4 Conclusion and perspectives References

Index

473 473 475 477 481 486 486 490

491 493 494 495 500 501 502 507

List of contributors

Abbi Abdel-Rehim Faculty of Science Manchester, Manchester, United Kingdom

and

Engineering,

University

of

Mohamed Abdel-Rehim Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institute and Stockholm County Council, Stockholm, Sweden; Functional Materials Division, Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, Isafjordsgatan 22, Kista, SE-164 40 Stockholm, Sweden Fabiana Arduini Department of Chemical Science and Technologies, University of Rome “Tor Vergata”, Rome, Italy Hirakendu Basu Analytical Chemistry Division, Bhabha Atomic Research Center, Trombay, Mumbai, India Basanti Brar Department of Animal Biotechnology, LLR University of Veterinary and Animal Sciences, Hisar, India Sibel Bu¨yu¨ktiryaki Yunus Emre Vocational School of Health Services, Department of Medical Services and Techniques, Anadolu University, Eskis¸ehir, Turkey Th.G. Chatzimitakos Department of Chemistry, University of Ioannina, Ioannina, Greece Jiping Chen CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian P.R. China Stefano Cinti Department of Pharmacy, University of Naples “Federico II”, Rome, Italy Gustavo Marques da Costa Technology and Environmental Management, Feevale University, Novo Hamburgo, Brazil

xii

List of contributors

Dhanjai Department of Mathematical and Physical Sciences, Concordia University of Edmonton, Edmonton, AB, Canada; Department of Physical Sciences, MacEwan University, Edmonton, AB, Canada; CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian P.R. China I˙brahim Dolak Vocational School of Technical Sciences, Dicle University, Diyarbakır, Turkey Weiyin Gao Department of Urology, The Second Affiliated Hospital of Nanchang University, Nanchang, P.R. China Mayukh Ghosh Department of Veterinary Physiology and Biochemistry, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, India Chaudhery Mustansar Hussain Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, NJ, United States Wei Jin National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, P.R. China Suresh Kumar Kailasa Department of Applied Chemistry, S. V. National Institute of Technology, Surat, India Ru¨stem Kec¸ili Yunus Emre Vocational School of Health Services, Department of Medical Services and Techniques, Anadolu University, Eskis¸ehir, Turkey Rajesh Kumar Department of Veterinary Physiology, COVAS, KVASU, Pookode, India Cheryl Suwen Law School of Chemical Engineering and Advanced Materials, The University of Adelaide, Adelaide, SA, Australia; Institute for Photonics and Advanced Sensing (IPAS), The University of Adelaide, Adelaide, SA, Australia; ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP), The University of Adelaide, Adelaide, SA, Australia Koodlur S. Lokesh Department of Chemistry/Industrial Chemistry, Vijayanagara Sri Krishnadevaraya University, Ballari, India Yang Luo Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, P.R. China; Center of Laboratory Medicine, Medical School of Chongqing University, Chongqing, P.R. China

List of contributors

xiii

Govindhan Maduraiveeran Material Electrochemistry Laboratory, Department of Chemistry, SRM Institute of Science and Technology, Kattankulathur, Tamil Nadu, India Lluı´s F. Marsal Department of Electronic, Electric, and Automatics Engineering, Universitat Rovira i Virgili, Tarragona, Tarragona, Spain Prasad Minakshi Department of Animal Biotechnology, LLR University of Veterinary and Animal Sciences, Hisar, India Mohammad Mahdi Moein Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institute and Stockholm County Council, Stockholm, Sweden Danila Moscone Department of Chemical Science and Technologies, University of Rome “Tor Vergata”, Rome, Italy Samuel M. Mugo Department of Physical Sciences, MacEwan University, Edmonton, AB, Canada Tae Jung Park Department of Chemistry, Institute of Interdisciplinary Convergence Research, Research Institute of Halal Industrialization Technology, Chung-Ang University, 84 Heukseok-ro, Dongjak-Gu, Seoul, Republic of Korea Harshad Sudhir Patki Department of Veterinary Anatomy and Histology, COVAS, KVASU, Pookode, India Xiaopei Qiu Department of Urology, The Second Affiliated Hospital of Nanchang University, Nanchang, P.R. China Shahadev Rabha Polymer Petroleum and Coal Chemistry Group, Materials Science and Technology Division, CSIR-North East Institute of Science and Technology, Jorhat, India Koushlesh Ranjan Department of Veterinary Physiology and Biochemistry, COVAS, SVP University of Agriculture and Technology, Meerut, India Marcin Runowski Faculty of Chemistry, Adam Mickiewicz University, Poznan´, Poland Binoy K. Saikia Academy of Scientific and Innovative Research, CSIR-NEIST Campus, Jorhat, India

xiv

List of contributors

Abel Santos School of Chemical Engineering and Advanced Materials, The University of Adelaide, Adelaide, SA, Australia; Institute for Photonics and Advanced Sensing (IPAS), The University of Adelaide, Adelaide, SA, Australia; ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP), The University of Adelaide, Adelaide, SA, Australia Viviana Scognamiglio Institute of Crystallography, Department of Chemical Sciences and Materials Technologies, Monterotondo Scalo, Rome, Italy Rakesh Kumar Singhal Analytical Chemistry Division, Bhabha Atomic Research Center, Trombay, Mumbai, India Ankita Sinha Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian, P.R. China Mustafa Soylak Faculty of Sciences, Department of Chemistry, Erciyes University, Kayseri, Turkey C.D. Stalikas Department of Chemistry, University of Ioannina, Ioannina, Greece Christine Vauthier Institut Galien Paris-Sud, UMR CNRS 8612, University ParisSud, Chatenay-Malabry Cedex, France Yingying Wen Environmental Science, Hainan Medical University, Haikou, P.R. China Erkan Yilmaz Faculty of Pharmacy, Department of Analytical Chemistry, Erciyes University, Kayseri, Turkey; Nanotechnology Research Center (ERNAM), Erciyes University, Kayseri, Turkey Hong Zhang Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, P.R. China Xianxian Zhao Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, P.R. China; Department of Laboratory Medical Science, Southwest Hospital, Third Military Medical University, Chongqing, P.R. China

Carbon nanodots from natural (re)sources: a new perspective on analytical chemistry

1

Th.G. Chatzimitakos and C.D. Stalikas Department of Chemistry, University of Ioannina, Ioannina, Greece

1.1

Introduction

Nanomaterials are unequivocally a unique class of materials with exceptional properties, which have fostered many unprecedented applications [1]. Carbon nanodots (CNDs) constitute a novel class of carbon-based nanomaterials, which were discovered in 2004 during the purification of single-walled carbon nanotubes. They possess strong and tunable fluorescence properties, which enable their applications in fields such as biomedicine, optronics, chemistry, and catalysis. These materials can further be functionalized with biomolecules, are less toxic, chemically inert, and can be used as effective carriers for drug delivery, biological imaging, and analytical applications. Compared with the traditional semiconductor quantum dots, the upconverting nanoparticles and the organic dyes, the photoluminescent (PL) CNDs show many advantages, including high photostability, high aqueous solubility, robust chemical inertness, and easy modification. In recent years, various chemical precursors have been identified for the synthesis of CNDs, including citric acid [2], ammonium citrate [3], ethylene glycol [4], phytic acid [5], EDTA [6], thiourea [7] and so on. Various synthetic routes have been used to convert these precursors into fluorescent CNDs, including hydrothermal [8,9], solvothermal [10], electrochemical treatment [11], microwave-assisted pyrolysis [12], ultrasonication [13], thermal carbonization [14], atmospheric plasma synthesis [15], chemical oxidation [16], exfoliation of graphite in organic solvent by modified Hummer’s method [17] and so on. Generally, CNDs are synthesized by both top-down and bottom-up methods motivating a constant persuasion of benign synthetic routes. The raw carbon sources for CNDs can be either man-made, for example, candle soot, graphite, fullerene-C60, ammonium citrate, glucose, urea, and ethylenediamine [18 22] or natural products (e.g., orange juice, milk, coffee grounds, green tea, egg, soy milk, flour, banana, potato, pepper, honey, garlic, aloe, rose flowers, hair, and rice husks) [15,23 38]. Nature offers a wealth of exciting precursors that inspire scientists to develop new materials with novel applications and less of an environmental or human impact. Natural products have an edge over chemical precursors. Firstly, they are renewable and have good biocompatibility. Handbook of Nanomaterials in Analytical Chemistry. DOI: https://doi.org/10.1016/B978-0-12-816699-4.00001-3 Copyright © 2020 Elsevier Inc. All rights reserved.

4

Handbook of Nanomaterials in Analytical Chemistry

Secondly, natural products contain heteroatoms, which facilitate the fabrication of heteroatom-doped CNDs without the addition of an external heteroatom source. Finally, some natural products can be used to prepare CNDs in ways that are green and simple relative to traditional methods, for the preparation of carbon dots from man-made carbon sources. As an additional benefit, the preparation of CNDs from natural products can convert low-value biomass waste into valuable and useful materials. Natural products that contain heteroatoms (N, S) are very suitable raw materials for the preparation of heteroatom-doped CNDs, unlike other N/S-doped CNDs derived from man-made carbon sources that require the addition of N/S-containing compounds. In this chapter, we will discuss the latest developments in CNDs with respect to natural (re)sources (the term “natural sources” henceforth will be used to describe natural sources, resources, and waste materials from natural (re)sources), as raw carbon and nitrogen and/or sulfur sources. The first part of the chapter focuses on the different methods that can be followed to produce CNDs from natural sources and their structural and PL characteristics to gain an insight into the unique properties of CNDs. The second part discusses particular applications of CNDs in analytical chemistry and the mechanisms involved in the fluorescence of CNDs.

1.2

Synthesis of carbon nanodots

The applications of CNDs rely, mostly, on their PL properties. Therefore, for the production of functional CNDs, these properties must be taken into account. In general, the PL of CNDs is derived, mainly, from the radiative recombination of surface energy traps and photoexcited electrons and leads to the emission of lower energy [39,40]. This type of emission depends on both the core and surface of the CNDs. Taking under consideration the above, it is conceived that the method employed and the respective conditions of the synthesis play a key role in the functional properties of the CNDs. Up to now, the synthetic approaches for producing CNDs have been divided into two main groups: the bottom-up and the top-down. The bottom-up methods, commonly, refer to the “grow” of precursor materials to CNDs. Methods that adhere to this approach, use simple carbonaceous materials, such as citric acid, glucose, and other simple compounds, as a source of nitrogen and/or sulfur, as a dopant [41,42]. However, these approaches are scarcely used to produce CNDs from natural sources [43]. Top-down approaches refer to the production of CNDs from macroscopic carbon sources, such as plants and waste (representative cases are presented in Fig. 1.1). Next, we will focus on these approaches owing to their widespread use in the production of CNDs from natural sources.

1.2.1 Solvothermal carbonization Solvothermal carbonization is the most widely employed approach to produce CNDs from natural sources. Typically, a sample from a selected natural source is

Figure 1.1 Schematic illustration of CND (CQDs: carbon quantum dots) synthesis using top-down approaches from (A) pyrolysis of Citrus sinensis and Citrus limon peels, (B) pyrolysis apple seeds, (C) pyrolysis of human fingernails, and (D) microwave treatment of human fingernails. Source: Reprinted from T. Chatzimitakos, A. Kasouni, L. Sygellou, I. Leonardos, A. Troganis, C. Stalikas, Human fingernails as an intriguing precursor for the synthesis of nitrogen and sulfur-doped carbon dots with strong fluorescent properties: analytical and bioimaging applications, Sens. Actuators B 267 (2018) 494 501; T. Chatzimitakos, A. Kasouni, L. Sygellou, A. Avgeropoulos, A. Troganis, C. Stalikas, Two of a kind but different: luminescent carbon quantum dots from citrus peels for iron and tartrazine sensing and cell imaging, Talanta 175 (2017) 305 312; A. Chatzimarkou, T. Chatzimitakos, A. Kasouni, L. Sygellou, A. Avgeropoulos, C.D. Stalikas, Selective FRET-based sensing of 4-nitrophenol and cell imaging capitalizing on the fluorescent properties of carbon nanodots from apple seeds, Sens. Actuators B 258 (2018) 1152 1160, with permission from Elsevier, and T. Chatzimitakos, A. Kasouni, A. Troganis, C. Stalikas, Carbonization of human fingernails: toward the sustainable production of multifunctional nitrogen and sulfur codoped carbon nanodots with highly luminescent probing and cell proliferative/ migration properties, ACS Appl. Mater. Interfaces 10 (2018) 16024 16032 from American Chemical Society.

6

Handbook of Nanomaterials in Analytical Chemistry

placed either directly or after specific pretreatment in an autoclave, along with water (hydrothermal) or organic solvent and the system is heated to a certain temperature (typically in the range of 180 C 280 C), for few hours. After completion of the procedure, the resulting liquid or viscous material (containing the CNDs) is subjected to further treatment to isolate or purify the CNDs. Simplicity, low cost, and environmental friendliness are the major advantages of this approach, which triggered the interest of research groups to employ it [30,33,43,47 49]. Multitudinous natural sources, including strawberry juice [49], aloe vera [33], wool [50], onion waste [51], water chestnut [52], dried lemon peel [53], etc., have yielded CNDs after hydrothermal treatment. Liu et al. produced N-doped CNDs (quantum yield (QY): 17.1%) from the hydrothermal treatment of goose feathers at 180 C for 40 min [54]. This amount of time is the shortest reported for the hydrothermal treatment process of a natural source. Contrary to the previous report, Zhang et al. spent 48 h to produce N-doped CNDs from egg white, after hydrothermal treatment at 220 C, but with significantly higher QY (i.e., 64%) compared with the previous case [55]. From the above two studies, it is easily concluded that aside from the carbon source, the conditions of the hydrothermal treatment, may significantly affect the produced CNDs. Xu et al., in an effort to produce N,S-doped CNDs from Enteromorpha prolifera showed that lower heating temperatures and shorter treatment periods of time (e.g., 150 C for 3 h) yield aggregated carbon nanoparticles with increased diameter (i.e., 30 140 nm) [56]. Increasing the temperature to 180  C reduced the aggregation of the carbon nanoparticles, while longer time (6 h) yielded, almost solely, nonaggregated CNDs. Further increase in temperature or time did not yield CNDs of higher fluorescence or better PL characteristics. Although temperature and time are the two determining factors for the production of CNDs from hydrothermal treatment, their effect cannot be predicted for all natural sources and thus a study of these two parameters is deemed necessary to yield functional CNDs with optimum PL properties [56]. In order to either shorten the time or reduce the heating temperature of hydrothermal treatment, He et al. and Yang et al. added H2O2 to cocoon silk and honey, respectively, to produce CNDs [31,57]. In the first case, the authors found that H2O2 has a vital role in reducing the time needed to realize the synthesis as well as in increasing the QY, compared with the addition of only water. Aside from altering temperature and time to obtain different CNDs, Fang et al. found that the addition of 0.2 M NaOH solution to soy flour yielded N-doped CNDs with higher QY (7.85%) compared with CNDs produced from the addition of water to soy flour (QY: 3.91%) [58]. Similarly, Edison et al. prepared N-doped CNDs by adding ammonia to Prunus avium fruit extract as an N-dopant to increase the QY of the CNDs [59]. In contrast, after proper treatment of prawn shells with alkaline and acidic media, Gedda et al. added acetic acid to the resulting material, prior to the hydrothermal treatment, making feasible the production of CNDs in acidic media [60]. The solvent is the last critical parameter that was normally considered during synthesis. Wang et al. prepared water-soluble and ethanol-soluble CNDs from papaya by adding the respective solvent to the autoclave along with the carbon

Carbon nanodots from natural (re)sources: a new perspective on analytical chemistry

7

source [47]. Both types of CNDs had similar structural and PL characteristics. Their differences focused mainly on their size, with the water-soluble CNDs to be nearly 6 nm smaller than their ethanol-soluble analogs. Vandarkuzhali et al. prepared CNDs from the pseudo-stem of banana plant using ethanol and heating in an autoclave [73]. The produced CNDs had an increased QY (48%) compared with other CNDs from hydrothermal treatment. All of the above examples bespeak the high potential of solvothermal methods to produce CNDs from natural sources, while the tunable parameters of the procedure permit the production of different products, with variable functionalities.

1.2.2 Pyrolysis Pyrolysis of a natural source is the easiest way to produce CNDs. Despite the simplicity, low cost, and environmental friendliness, this method is less often used, compared with solvothermal carbonization. This can be attributed to the fact that the main parameters (i.e., pyrolysis time and temperature), except for the selected precursor material which directly affects the produced CNDs, cannot result in CNDs with different PL properties or structural characteristics. Typically, the starting material is heated at high temperature (commonly above 200 C), for a certain period of time, after which a black carbonaceous material is obtained. Following grinding in a mortar and some purification/isolation steps, CNDs are obtained [43,44]. Teng et al. synthesized N-doped CNDs by pyrolyzing konjac flour at 470 C, for 1.5 h [61]. After completion of the pyrolysis, the obtained black residue was ground to a fine powder. Ethanol was added to the powder and left under stirring overnight to extract the CNDs (QY: 13%). Similarly, Xue et al. prepared CNDs from pyrolysis of Lychee seeds (QY 10.6%) at 300 C for 2 h [62]. In this case, the authors added water to the black powder and after ultrasonication and filtration, they obtained the CNDs. Zhu et al. prepared CNDs from plant leaves (e.g., oriental plane leaves, pine needles, camphor leaves, bamboo leaves) (QY: 11% 16%) by heating them at temperatures between 250 C and 400 C for 2 h [63]. The authors found that the optimum temperature was close to 300 C, as carbonization at lower temperatures was insufficient owing to the high content of water in the selected leaves. Our research group prepared CNDs from Citrus sinensis (i.e., orange) and Citrus limon (lemon) peels [44]. Both fruits are the most widely produced and consumed species, resulting in high amounts of inedible peels that can serve as an excellent natural source for the production of CNDs. Heating the peels at 180 C for 2 h yielded CNDs with QYs of 16.8% and 15.5% for C. sinensis and C. limon peels, respectively. In this case, the temperature used for the pyrolysis is the lowest reported, making this approach suitable for the massive production of CNDs. In another study, we produced N-doped CNDs from apple seeds by pyrolysis, at 300 C for 1 h. After purification, the obtained CNDs had a QY of 20%. This was the first attempt to use seeds in synthesis; what is more, a common waste from food industries was utilized to produce a functional material. Lastly, pyrolysis was the

8

Handbook of Nanomaterials in Analytical Chemistry

choice for the preparation of CNDs from human fingernails at 200 C, for 3 h [46]. The produced CNDs, in this case, are the brightest reported so far with a QY of 81.4%.

1.2.3 Microwave treatment Employing microwaves to hasten the production of CNDs is an up-and-coming trend in this field. The high efficiency of the method, along with the rapidity and environmental friendliness are the main advantages over other top-down methods [43]. Typically, the natural source is placed in a suitable solvent/solution and then heated using microwaves. Using this concept, Majumdar et al. prepared CNDs by irradiating a hydroethanolic solution of filter paper ash for 10 min. The resulting CNDs had a relatively high QY (i.e., 35.8%) [64]. In another study, Wang et al. prepared N,S-doped CNDs (QY: 16.3%) by placing wool and water in a microwave digestion tank and heating at 200 C for 1 h, using microwave [50]. Feng et al. prepared CNDs by mixing rose petal powder, water, and P2O5, and treated the solution in a microwave oven, until color change [34]. The produced CNDs had a QY of 13.4%. In our laboratory, we synthesized N,S-doped CNDs by microwave treatment of human fingernails [39]. A portion of fingernails was placed in a glass beaker along with concentrated H2SO4 and was irradiated at 400 W, for 2 min. The QY of the obtained CNDs was 42.8%. This strategy not only avoids the use of toxic or expensive solvents and starting materials but also provides an effective way to reclaim nail wastes. It is noteworthy that the CNDs are produced using a domestic microwave, negating the need for sophisticated equipment. Even more importantly, the employed method is energy-efficient and fast.

1.3

Characteristics of carbon nanodots

It is easily understood that using one of the aforementioned methods of synthesis and a natural source as a precursor, a variety of CNDs with different characteristics can be produced. Despite the potentially large number of CNDs, they share in common structural or spectral properties. Below, we will focus on the characteristics of the CNDs utilized in analytical applications and prepared from natural sources.

1.3.1 Structural characteristics Regardless of the synthetic approach and the precursor materials (either natural sources or pure substances), CNDs have a lot in common. According to their chemical composition, CNDs can be divided into three main groups, as follows: the nondoped, the N-doped, and the N,S-doped CNDs. Although CNDs doped with other heteroatoms can be produced using suitable chemical precursors, up to now there have been no reports of such CNDs from natural sources.

Carbon nanodots from natural (re)sources: a new perspective on analytical chemistry

9

1.3.1.1 Nondoped carbon nanodots The simplest form of the CNDs (in terms of chemical composition) is that of the nondoped, with any heteroatom, which consist solely of carbon, oxygen, and hydrogen atoms. Although it seems easy to synthesize nondoped CNDs, it is difficult to obtain them because of the high content of natural sources in heteroatom-containing molecules. Thus, doping may be inevitable in many cases. Up to now, nondoped CNDs have been synthesized from bovine serum albumin [65], rose flowers [34], lemon peels [66], sweet potato [29], Ocimum sanctum [67], sugarcane molasses [68], petroleum coke [69], apple juice [70], lemon juice [71], Chinese yams [72], dried lemon peels [53], pseudo-stem of banana plant [73], sweet red pepper [30], and diesel engine soot [74]. The QYs of these CNDs range between 1.9% and 19.3%.

1.3.1.2 N-doped carbon nanodotss As mentioned above, natural sources can provide CNDs with heteroatom doping. Among the different heteroatoms, nitrogen is in high abundance, as it is found in many (macro) molecules, such as amino acids, nucleic acids, proteins. The majority of the published articles regarding the synthesis and utilization of CNDs from natural sources, present N-doped CNDs. Lotus root [75], grass [76], pomelo peel [48], roseheart radish [77], cocoon silk [57], prawn shells [60], lignite [78], and human urine [79] are some examples of precursor materials used so far. Doping of CNDs with nitrogen can dramatically alter their PL properties, as will be discussed later on.

1.3.1.3 N,S-(co)doping Although one would expect that doping of CNDs from natural sources with sulfur would be rather ordinary, the published reports of either S- or N,S-co-doped CNDs, are scanty and sparse. Lin et al. prepared S-doped CNDs from hydrothermal treatment of newspaper ash (QY: 20%) [80]. Hu et al. and Wang et al. prepared N,S-codoped CNDs from water chestnut [52] (QY: 12%) and wool [50] (QY: 16.3%). In our laboratory, we prepared N,S-co-doped CNDs from pyrolysis or microwave treatment of human fingernails [39,46]. The main reasons that make feasible the doping of the CNDs with sulfur or other heteroatoms still remain unknown. However, it is believed that in order to induce sufficient heteroatom doping, a large number of heteroatom precursors are needed [81]. Although almost all natural resources contain sulfur in different forms, their content should be high enough, in order to obtain S-doped or N,S-co-doped CNDs.

1.3.2 Spectral properties and chemical stability of carbon nanodots 1.3.2.1 Ultraviolet absorption As stated earlier, despite the different precursors or synthetic methods, the CNDs share in common certain characteristics. One such spectral characteristic is the

10

Handbook of Nanomaterials in Analytical Chemistry

strong absorption in the ultraviolet (UV) region, which extends in the form of a tail in the visible region [82]. Nonetheless, there are also differences in the UV spectra, which vary with respect to the precursors employed and the synthetic procedures. Representative spectra are shown in Fig. 1.2. Most of the synthesized CNDs show an absorption band at B280 nm [47,56,65,78,83 86], which is typical of π aromatic systems. This peak is attributed mainly to the π π and n 2 π transitions of C 5 C and C 5 O bonds, respectively, while in some cases a peak/shoulder at B300 nm appears due to n 2 π or π 2 π transitions of COO2 or C O C bonds, respectively [87]. Although not common, other peaks can also appear in the UV spectra. For instance, Majumdar et al. prepared CNDs from filter paper ash [64] and the received UV spectrum showed two intense peaks, the first one at 205 nm and the second one at 240 nm. The authors attributed the former to the σ σ transitions of electrons, which require high energy and the latter to lone pair electrons that require low energy to transit from n to σ . Another case is the appearance of a peak at B330 nm. It is speculated that the CNDs, which have such an absorption peak, have increased QYs due to trapping of excitation energy from surface energy traps that result in a strong emitted PL [88,89]. Such an example is the CNDs that we prepared in our laboratory from pyrolysis of human fingernails [46]. The UV spectrum of CNDs exhibits a peak at 330 nm and their QY is 81.4%.

1.3.2.2 Photoluminescent properties Photoluminescence is the most important property of CNDs to be made use of in applications. In general, PL describes bandgap transitions, owing to conjugated p domains [90]. After photoexcitation, electrons jump to (permissible) excited states, and when returning to the ground state, energy is released either by emitting light or not through a radiative or a nonradiative process, respectively. In the first case, downconversion or upconversion PL is applicable, depending on the energy of the emitted photon.

1.3.2.2.1 Downconversion Downconversion PL refers to the emission of two photons of lower frequencies from one photon of higher frequency. This is the most common type of PL among CNDs, in general, and even more the one produced from natural sources. The PL emission of CNDs extends to all visible-range spectrum. The exact mechanism that is responsible for the PL still remains unknown, although it is speculated that many different factors (e.g., surface states/groups/passivation, doping, size, and defects) contribute to the overall observed phenomenon to a different extent [91]. It is noteworthy that the majority of the published articles report CNDs whose PL emission is excitation-dependent. An increase in the excitation wavelength is often accompanied by a red shift and a change in the intensity of the PL emission. This is mainly attributed to the presence of significant surface defects [92]. Although widely used, these CNDs have drawbacks concerning their applicability, as Chen et al. have stated [93]. The employment of different monochromatic excitation light sources and the fact that, often, the long-wavelength emissions have low

Figure 1.2 Representative UV Vis spectra of CNDs from (A) pyrolysis of Citrus sinensis and Citrus limon peels, (B) pyrolysis apple seeds, (C) pyrolysis of human fingernails, and (D) microwave treatment of human fingernails. Source: Reprinted from T. Chatzimitakos, A. Kasouni, L. Sygellou, I. Leonardos, A. Troganis, C. Stalikas, Human fingernails as an intriguing precursor for the synthesis of nitrogen and sulfur-doped carbon dots with strong fluorescent properties: analytical and bioimaging applications, Sens. Actuators B 267 (2018) 494 501; T. Chatzimitakos, A. Kasouni, L. Sygellou, A. Avgeropoulos, A. Troganis, C. Stalikas, Two of a kind but different: luminescent carbon quantum dots from citrus peels for iron and tartrazine sensing and cell imaging, Talanta 175 (2017) 305 312; A. Chatzimarkou, T. Chatzimitakos, A. Kasouni, L. Sygellou, A. Avgeropoulos, C.D. Stalikas, Selective FRET-based sensing of 4-nitrophenol and cell imaging capitalizing on the fluorescent properties of carbon nanodots from apple seeds, Sens. Actuators B 258 (2018) 1152 1160, with permission from Elsevier and T. Chatzimitakos, A. Kasouni, A. Troganis, C. Stalikas, Carbonization of human fingernails: toward the sustainable production of multifunctional nitrogen and sulfur codoped carbon nanodots with highly luminescent probing and cell proliferative/migration properties, ACS Appl. Mater. Interfaces 10 (2018) 16024 16032 from American Chemical Society.

12

Handbook of Nanomaterials in Analytical Chemistry

intensities are two discouraging factors for using such excitation-dependent CNDs. On the contrary, there are CNDs with excitation-independent PL properties; yet, such reports are quite rare [91]. Lately, Maiti et al. addressed this problem and stated that the methods used to produce excitation-independent emission are either complex or yield CNDs with low QY [92]. In this context, Majumdar et al. prepared CNDs with excitation-independent properties from the microwave treatment of filter paper ash [64]. Similarly, our research group prepared excitation independent CNDs from the carbonization of C. sinensis and C. limon peels, as well as from the carbonization and acid treatment of human fingernails [39,44,46]. With respect to the excitation-dependent CNDs, the developed CNDs have maxima of λex/λem at B340 6 20 nm/B430 6 25 nm, in most of the reported cases [31,49,55,60,72,77,86,90,94,95]. Furthermore, a single-emission peak is observed, which shifts according to the excitation wavelength. Therefore, multicolor CNDs can be produced. There are also reported cases of CNDs that have maxima of λex/ λem at B420 6 20 nm/B510 6 10 nm [53,67,69,71,73,74,96]. An intriguing aspect of some CNDs is that they can potentially have dual PL emission. In other words, instead of the emission wavelength transitions (i.e., multicolor emission), two emission maxima are observed, whose intensity varies with the excitation wavelength. This is often observed in the excitation-independent CNDs. For instance, CNDs produced from carbonization of human fingernails have λem at 380 and 450 nm for λex at 330 and 370, respectively [46]. Similarly, CNDs from acid treatment of human fingernails have λem at 380 and 430 nm for λex at 320 and 250, respectively [39]. In the latter case, the first emission peak was due to the high-energy n π transitions, while the second peak was due to the generation of intermediate states between the highest occupied molecular orbital and the lowest unoccupied molecular orbital, owing to heterogeneity of surface (organic) groups.

1.3.2.2.2 Upconversion Upconversion is the combination of two photons, in a way that a single, higherenergy photon is produced. Reports of CNDs with upconversion properties are scanty and sparse. Yin et al. prepared CNDs with both upconversion and downconversion properties from sweet pepper [30]. In relation to downconversion, optimum λem was at 450 nm for λex at 360 nm, while for upconversion, the λem was between 400 and 600 nm and for λex ranging between 780 and 900 nm. The QY of the CNDs was found to be 19.3%. This report is the only presented case of CNDs, deriving from natural sources, with upconversion properties. Such CNDs are particularly useful in in vivo imaging applications [97].

1.3.2.3 Photoluminescence stability The photostability or PL is a key factor for the use of CNDs in PL-based applications. There are three different types of measured photostability: the stability after long-time continuous excitation, the stability of a solution after several days and the stability of CNDs (in powder) in relation with the storage time [44]. Virtually all

Carbon nanodots from natural (re)sources: a new perspective on analytical chemistry

13

produced CNDs have good photostability after continuous irradiation for at least 1 or 2 h [33,45,65], or even after 7 h of irradiation with a 500-W Xe lamp [49]. Concerning photostability with storage time, solutions are stable even after 1 week [45,65] of storage, while CNDs are stable even after 6 months [45]. Another aspect of CND PL is their pH-sensitive behavior. Because of their content in ionizable groups, such as carboxyl, amino, and hydroxyl groups, the local surface environment alters as a function of the pH of the solution. Thus, their PL varies accordingly [97]. Typically, most CNDs have a constant PL emission in a pH range between 4 and 10. Beyond this range, the PL emission is dramatically decreased. In some other cases, CNDs proved to be stable in different pH values. For instance, Liu et al. prepared CNDs from rose-heart radish, which showed stable PL at pH 2 7 [77]. Hoan et al. prepared CNDs from lemon and their PL was stable in the pH range of 1 12 [71]. Wang et al. prepared CNDs from shiitake mushroom that were highly sensitive to the pH of the solution [98]. In fact, due to the high sensitivity of the CNDs to pH, the researchers utilized them for the development of a pH probe, which could be also used in biological systems. The last parameter often examined, is the tolerance of CNDs to salt(s) or, in other words, the effect of ionic strength on the PL emission. Typically, CNDs are stable in solutions of high salt content [44,45]. Thus, they can be used in relevant applications where high ionic strength may pose a challenge.

1.4

Analytical applications of carbon nanodots fluorescence systems

The unique PL properties of the CNDs enable their use in many applications. Among others, the development of fluorescent probes using CNDs has become quite popular, because they can be used to detect a broad range of analytes. The simplest case is the quenching of the emitted fluorescence signal of CNDs from a target molecule due to some interactions (vide infra) with the CNDs. The second case is the development of more complex probing systems. The fluorescence is quenched from a target molecule, as in the first case, but then it is recovered by adding a second molecule, which “breaks” the first quenching combination [99]. Thus, from the quenching of the fluorescence and its recovery, a dual probing system can be developed. In the following sections, we will focus on the analytical platforms that have been developed, using CNDs from natural sources.

1.4.1 Cations—metal ions The most frequent type of probes developed using CNDs is that for the detection of cations. Almost exclusively, probes for cation were developed for detecting metal ions such as ferric, mercury and copper ions.

14

Handbook of Nanomaterials in Analytical Chemistry

1.4.1.1 Ferric ions Ferric ions are important for the physiological function of biological systems as well as they are an important component in the environment. Thus, the monitoring of their levels, either in biological or environmental systems is deemed necessary. In fact, ferric ions are the most commonly reported ions for which CND-based probes have been developed. This is probably due to their oxygen-rich surface groups of CNDs. The different surface groups, the QY and the PL characteristics of CNDs affect their suitability for analytical purposes. Thus the reported probes for ferric ions (summarized in Table 1.1) have different sensitivity and they can be applied to different matrices. In many cases, the developed probing systems were applicable to monitoring ferric ions in water matrices [29,31,51,54 56,58,59,61,63,68,73,77,84 86,95,96,100]. The limits of detection (LODs) of these probes range between 0.021 and 100 μM and the linear ranges are commonly between 1 and 100 μM, as it can be seen in Table 1.1. Xu et al. developed an analytical system for ferric ions using CNDs from the biomass of E. prolifera, which has the widest reported linear range (1 370 μM and 400 1700 μM) [56]. Aside from the detection of ferric ions in water, probes were also developed for other matrices. Zhang et al. produced CNDs from human hair or pig skin and because of their biocompatibility, they used them to detect, among others, ferric ions in zebrafish, with a wide linear range (1 1600 μM) [94]. Most importantly, the CNDs could be excreted from the digestive system, so that no potential damage due to long-term exposure to CNDs could be observed. Wang et al. developed a ferric ion probe from papaya, which had a wide linear range (1 8 and 10 800 μM) and it was successfully applied to the detection of ferric ions in heme capsules [47]. Yang et al. and our research group synthesized CNDs from honey and C. sinensis peels, respectively [31,44]. The two probing systems had similar analytical figures of merit; both achieved the lowest reported LODs (0.003 and 0.0017 μM for C. sinensis- and honey-derived CNDs) and comparable linear ranges (0.01 100 and 0.005 100 μM, respectively). Both of them were found to be highly efficient for the detection of ferric ions in human blood, while C. sinensis peels-derived CNDs could also be used in water and human urine samples.

1.4.1.2 Mercury ions Mercury ions are well known for their toxicity. As they pose a major threat to human health, strict regulations exist regarding their maximum tolerant concentration in food and water samples. The need for sensitive and reliable detection of mercury ions remains high. In this context, research groups have developed mercury ion probes using CNDs [48,49,70,72,75,79]. In most cases, the LODs are close to 3 nM and the linear range is between 1 and 60 μM. Lu et al. developed an ultrasensitive method, using CNDs from pomelo peel [48]. The developed probe had a LOD of 0.23 nM (the lowest reported, as yet) and two linear ranges (i.e., 0.5 10 and 500 4000 nM), making it suitable for routine analysis.

Table 1.1 Analytical figures of merit for CND-based ferric ion-probing systems. Carbon source

Preparation method

λex/λem (nm)

QY (%)

Matrix

LOD (µM)

Linear range (µM)

Reference

Sweet potato Honey Papaya Onion waste Goose feathers Egg white Enteromorpha prolifera Soy flour Prunus avium Citrus sinensis peels Konjac flour Plant leaves Sugarcane molasses Pseudo-stem of banana Rose-heart radish Wheat straw

HT HT HT HT HT HT HT

360/442 340/420 370/450 380/464 340/410 315/420 320/440

8.64 19.8 18.9 28 17.1 61 12.3

Water Blood Heme capsules Water River water Water Tap water

0.32 0.0017 0.29 0.31 0.196

[29] [31] [47] [51] [54] [55] [56]

HT HT Pyrolysis

350/440 310/411 365/455

7.8 13 16.8

0.021 0.96 0.003

Pyrolysis Pyrolysis HT

383/434 370/420 305/390

13 11 16 5.8

Water Water Water, urine, and blood Water Water Water

0 100 0.005 100 1 8 and 10 800 0 20 2 7 50 250 1 370 and 400 1700 0 5 0 100 0.01 100

— — 1.46

0 5 0 100 0 100

[61] [63] [68]

HT

420/500

48

Water

0.065

0 100

[73]

HT

330/420

13.6

River water

0.13

0.02 40

[77]

HT

9.2

Water

1.95

1.95 250

[84]

Curcumin Mangosteen pulp Pig skin Human hair Limeade Cornstalk Coriander leaves

HT Pyrolysis HT

304/418 and 364/464 340/460 330/440 320/380

8.6

Water Water Zebrafish

0.62 0.052 —

0 6 0 180 0 1600

[85] [86] [94]

HT HT HT

325/490 410/500 320/400

Water Water Water

100 0.21 0.4

— 0 18 0 6

[95] [96] [100]

HT, hydrothermal treatment.

51 86 7.6 6.48

0.5

[58] [59] [44]

16

Handbook of Nanomaterials in Analytical Chemistry

1.4.1.3 Copper ions Copper ions are essential for maintaining the well-being of humans and other living organisms. However, high concentrations can cause acute toxicity problems. Up to now, four fluorescent systems for copper ions that employ CNDs from natural sources have been developed [60,69,76,78]. Grass was used by Liu et al. to prepare CNDs, whose PL can be quenched selectively by copper ions [76]. The fluorescence quenching was found to be linear at copper concentrations of 0.05 0.5 nM and 1 50 μM. Similarly, CNDs from lignite were used to develop an ultrasensitive copper probe, whose LOD was 0.0089 nM [78]. The variability of LODs and linear ranges of the reported probes make them suitable for monitoring copper ions in different matrices.

1.4.1.4 Other (heavy) metal ions In addition to the fluorescent systems reported so far, there are certain reports for CND probes for other metal ions. Wee et al. and Kumar et al. developed sensors for lead ions using bovine serum albumin- and O. sanctum-derived CNDs [65,67]. The first system had a linear response for lead concentration up to 6 μM and an LOD of 5.05 μM [65]. The second one has much lower LOD (0.59 nM) and a linear range of 0.01 1.0 μM [67]. Tyagi et al. produced CNDs from lemon peel waste and utilized them to develop a probing system for Cr(VI) ions [66]. The linear range of the probe was 2.5 50 μM and the LOD was 73 nM. Our research group developed an ultrasensitive probe for Cr(VI) using CNDs from carbonization of human fingernails [46]. The reported system has an ultra-low LOD (0.3 nM) and a linear range of 1.7 67.5 nM, and it is also suitable for the speciation of chromium species. A fluorescence system for molybdenum ions was developed using CNDs from lemon juice by Hoan et al. [71]. Although this is the only reported probing system for this ion, the LOD of B200 μM and the selectivity of the CNDs toward ferric and ferrous ions also hinders its applicability, without further optimization.

1.4.2 Organic molecules In the cases of cations (mostly ferric ions), the static quenching is the mechanism that is responsible for the observed PL quenching (i.e., formation of ground state complex, vide infra). Capitalizing on different mechanisms and interactions that can occur between CNDs and organic molecules, selective probes can be developed for the detection of organic molecules. In fact, probing systems based on the PL of CNDs have been used for target analytes with environmental, biological, and nutritional interest.

1.4.2.1 Analytical systems for food components Carmine, tartrazine, and sunset yellow are food colorants for which CND-based probing systems have been developed. The use of all three is still controversial, due to health problems that may arise from their extensive consumption [39,44,53].

Carbon nanodots from natural (re)sources: a new perspective on analytical chemistry

17

Anmei et al. produced CNDs from hydrothermal treatment of dried lemon peels, which served as a probe for carmine in soft drinks [53]. In a similar manner, our research group and Xu et al. developed PL systems for tartrazine using CNDs from C. limon peels and aloe, respectively [33,44]. The two probes had similar linear range (i.e., 0.6 23.5 μM for aloe CNDs and 0.25 32.5 μM for C. limon CNDs) and LODs (73 nM for aloe CNDS and 60 nM for C. limon CNDs), while both were successfully applied to the detection of tartrazine from food matrices, such as steamed buns, honey, and candy using aloe CNDs; and ice-cream, juice, and energy drinks from C. limon CNDs. Likewise, human fingernails and sugarcane molasses were used as natural sources to produce CNDs, which served as PL probes for sunset yellow [39,68]. The system developed by Huang et al. was not sufficiently sensitive to detect sunset yellow (LOD: 0.399 μM) because of weak interactions between the sunset yellow and the synthesized CNDs, as stated by the authors [68]. Another probing system was reported to be ultra-sensitive, as the PL of the CNDs could be quenched even by 0.1 nM (LOD) of sunset yellow [39]. Another probe with wider applicability was developed by Majumdar et al., which can detect the total sulfur content of a sample and quantify the organic and inorganic sulfur [64]. The CNDs prepared from filter paper ash were further capped with Au31 and the PL of the conjugate could be enhanced in the presence of organic molecules containing sulfur, while a decrease was apparent in the presence of inorganic molecules containing sulfur. The developed probe was used to detect sulfur-containing molecules (such as cysteine and methionine) in milk.

1.4.2.2 Probes for analytes of environmental importance Over the last years, more and more research groups have tried to develop new and robust techniques for the detection of organic pollutants in the environment. This is because legislation regarding the maximum permitted concentrations of various analytes in the environment is getting stricter and due to the demonstrated detrimental effect that many molecules have. Thus, methods that could be used “onsite” are of high demand. Analytical systems based on CNDs have high potential in environmental analysis. On account of this, Wang et al. prepared CNDs from wool, whose PL can be quenched from silver nanoparticles, via inner filter effect [50]. The absorption of silver nanoparticles depended on the interparticle distance. In the presence of other molecules, silver nanoparticles tended to aggregate. Thus, their absorption was altered and the PL of the CNDs would be recovered. Although this seems like the “off on” systems, which will be discussed later on, the main difference is that the “off” state, due to the presence of silver nanoparticles is not used for analytical purposes, but mainly as an intermediate step in order to achieve the “on” state and the actual probing. Owing to the positively charged surface of silver nanoparticles, glyphosate is an excellent candidate to aggregate the nanoparticles and, therefore, to recover the PL of the CNDs. The proposed system achieved low LODs (12 μg L21) and could be used in cereal samples with satisfactory recoveries. In a similar manner, Lin et al. developed a probe for the detection of organophosphorus pesticides, employing CNDs from waste paper ash [80]. In fact, the CNDs

18

Handbook of Nanomaterials in Analytical Chemistry

were sensitive to ferric ions. The authors took advantage of the production of H2O2 from acetylcholine by acetylcholinesterase, which can be disrupted in the presence of organophosphorus pesticides (Fig. 1.3). Thus, in a solution containing ferrous ions, when the production of H2O2 was halted, no oxidation of ferrous ions to ferric ions occurred, so no quenching of the CND PL was observed. Although this probing system seems rather complicated, it makes it possible for total organophosphorus content to be determined in a single analysis. Nitrophenols are known for their deleterious effect and are considered priority pollutants due to the difficulty to remove from the environment, as a result of their stability [45]. Liang et al. and our research group prepared CNDs from bamboo tar and apple seeds, respectively, which were utilized to develop PL analytical systems for nitrophenols [45,101]. Specifically, the CNDs from bamboo tar were sensitive to the presence of 2,4,6-trinitrophenol and the respective probe had an LOD of 33 nM [101]. The CNDs from apple seeds were sensitive to the presence of 4-nitrophenol and the LOD of the developed system was 13 nM [45]. Other ordinary classes of environmental pollutants are organic dyes and pharmaceuticals. Feng et al. prepared CNDs from rose flowers, which were highly sensitive to tetracycline; an analytical system was developed, which had a very low LOD (3.3 nM) [34]. Xue et al. prepared CNDs from lychee seeds whose PL could be

Figure 1.3 Probing principle of organophosphorus pesticides using a ferric ion PL probe, based on CNDs. Source: Reprinted from B. Lin, Y. Yan, M. Guo, Y. Cao, Y. Yu, T. Zhang, et al., Modification-free carbon dots as turn-on fluorescence probe for detection of organophosphorus pesticides, Food Chem. 245 (2018) 1176 1182, with permission from Elsevier.

Carbon nanodots from natural (re)sources: a new perspective on analytical chemistry

19

quenched in the presence of methylene blue [62]. A linear range of 0.2 10 μM and an LOD of 50 nM are the analytical characteristics of this probe for the detection of this dye.

1.4.2.3 Probing analytes of biological importance The monitoring of various molecules of biological importance is deemed necessary, either for maintaining the well-being of people or for the advancements of medicine. Tripathi et al. highlighted the potential of CNDs from diesel engine soot for the detection of cholesterol, a molecule of high importance, because of its correlation with many heart and blood circulation diseases [74]. Wang et al. proposed a system for the detection of hemin using CNDs from shiitake mushroom [98]. The peroxidase-mimicking activity of this metalloporphyrin renders it an active cofactor of many enzymes and its detection is important for biomimetic catalysis. The developed analytical system achieved a low LOD (120 nM) and a linear range of 0.4 8.0 μM. As happens with many drugs, overdose can cause adverse effects in the body. Therefore, in some cases, monitoring of the levels of a drug is important, so that a “physiological” level is maintained. Thioridazine and 6-mercaptopurine are two drug molecules, for which PL probes have been developed [72,83]. Although the probe for thioridazine is not as sensitive as that for 6-mercaptopurine, the development of both is very important, as they provide an easy, low cost, and fast method to detect these molecules in real-time conditions. In many cases, in order to understand the pathogenesis of a disease or to develop a detection method to alleviate symptoms, such as fatigue and irritability, the levels of coenzyme A should be monitored [52]. Hu et al. prepared a relevant system, which could detect up to 10 nM of coenzyme A, using CNDs from water chestnut [52]. Aside from the detection of ferric ions, the CNDs prepared from human hair and pig skin by Zhang et al. can also serve as a probe for ATP and NADH in zebrafish [94]. Both molecules are vital for the energy production of cells in all organisms. The development of this probing system can be particularly useful to monitor metabolic processes in organisms.

1.4.3 “Off On” CND-based PL systems The principle which “off on” systems are based on was discussed above. Using this approach, Li et al. prepared a probe for 6-mercaptopurine by modifying CNDs with carboxyfluorescein-DNA macro-molecules, which could also detect mercury ions from the recovery of PL [72]. Specifically, CNDs and carboxyfluoresceinDNA macro-molecules can be conjugated in the presence of 6-mercaptopurine, resulting in quenching of the CND PL. However, in the presence of mercury ions, specific interactions between DNA and mercury are developed breaking the integrity of the initial conjugate and thus, recovering the PL of the CNDs. Teng et al. and Vandarkuzhali et al. developed two “off on” systems [61,73]. In both cases, fluorescence quenching was achieved in the presence of ferric ions. In the first

20

Handbook of Nanomaterials in Analytical Chemistry

case, PL was recovered after the addition of L-lysine [61] and in the second one, thiosulfate ions restored the PL [73]. All of the aforementioned reported cases highlight the tremendous potential of CNDs to develop multitudinous analytical systems with diverse characteristics, for numerous target molecules or ions. Such fluorescence probing systems can be applied to several areas, from food to environmental and biological analysis, while their selectivity, sensitivity, and easiness are unrivaled by other techniques. Although similar probing systems have been developed using CNDs which were produced from pure substances, there are some benefits in using natural sources. Underutilized natural sources, usually of negligible cost are used, lowering the cost of the production of CNDs and that of analysis. Also, it can be inferred that the use of natural sources is a green alternative to using pure substances; thus, the developed fluorescence systems are more environmentally friendly. In addition, most CNDs from natural sources are self-passivated because of the presence of many molecules in the natural source, negating the need for further passivation/functionalization. Doping with heteroatoms, which in many cases is important to develop a PL probe of high potential, is rendered easier. All of the above, highlight the benefits of developing PL probes using CNDs from natural sources.

1.5

Mechanisms of CND-based photoluminescent analytical systems

All of the above CND probes rely on the PL quenching to achieve detection of the target analytes. The quenching of the PL (it refers to all the changes in PL intensity) can be achieved through different mechanisms [90]. Moreover, the observed PL quenching can frequently be the result of more than one involved mechanism. Herein, we will overview the four mechanisms that are most commonly responsible for setting up the analytical probes. It is worth mentioning that the mechanisms discusses herein are not operative only for CNDs from natural sources, but also are valid for all CND-based PL probes, regardless of the precursor material (either a natural source or a pure substance) employed to prepare CNDs.

1.5.1 Static quenching Static quenching refers to the formation of a nonfluorescent ground state complex, between CNDs and an analyte [102]. When the complex absorbs light, no photon emission is observed. This mechanism can result in alterations of the absorption spectra of CNDs. As a complex is formed, increased temperatures hinder the formation or reduce the stability of such complexes. Thus, it can be inferred that in case that static quenching mechanism dominates, temperature affects negatively the sensitivity of the developed probe.

Carbon nanodots from natural (re)sources: a new perspective on analytical chemistry

21

1.5.2 Dynamic quenching The charge transfer or energy transfer that occurs between CNDs and a molecule via collision is called dynamic quenching [102]. This type of mechanism is different from static quenching, as only the excited states are affected (thus no alterations in the absorption spectra are observed). In this case, as temperature increases, molecules and CNDs have higher kinetic energy and therefore, the number of collisions increases, resulting in increased PL quenching.

1.5.3 Inner filter effect The inner filter effect refers to the case that either the excitation or the emission spectrum of the CNDs overlaps with the absorption spectrum of a compoundanalyte. Although it is not exactly about a “quenching” process, it is referred to as apparent or deceptive quenching, because either attenuation of excitation energy or absorption of the emission radiation occurs [99,102]. Although mechanistically different from static- or dynamic-quenching mechanisms, inner filter effect is absolutely exploitable for probing purposes [44,103].

1.5.4 Fo¨rster resonance energy transfer Fo¨rster resonance energy transfer (FRET) is an electrodynamic process that takes place between the excited state of CNDs and the ground state of the quencher molecule. The excited CNDs return to the ground state and energy is transferred, without the appearance of photons (because of long-range dipole dipole interactions), to the ground state of the quencher to ascend to the excited state [99,102]. In order for FRET to be applicable, some criteria need to be met. First, the “donor” molecule (e.g., CNDs) must have the ability to produce fluorescent light. Second, there should be a spectral overlap between the fluorescence emission spectrum of the donor and the UV absorption spectrum of the acceptor (quencher molecule). Finally, the distance between the donor and the acceptor must be ,8 nm [46].

1.6

Conclusions

For the commercial production of CNDs, one should be concerned with the cost and availability of the precursor and also with the ease of synthesis, energy and time consumption, and cost of sophisticated instruments, materials, and methods. Although much research effort has been devoted to the development of new natural resources, novel synthetic methods, new applications, materials, and devices with better performance, some challenges still remain. In the future, more effort should focus on the preparation of CNDs with near-infrared absorbance and emission. Near-infrared light is preferred to UV Vis light for bioanalytical applications, as near-infrared light can penetrate deep into tissues and has low biological toxicity. Along these lines, upconverting emission is a very interesting phenomenon by

22

Handbook of Nanomaterials in Analytical Chemistry

which CNDs emit visible fluorescence upon excitation with near-infrared light. To realize the full potential of green CNDs, research efforts should be directed toward heavy metal ions. Also, the readily detected metals should be targeted for the simultaneous multiple metal detection with appreciable selectivity and sensitivity, which may lead to the fabrication of devices for real-time detection.

References [1] Javier Gonza´lez-Sa´lamo, Ba´rbara Socas-Rodrı´guez, Antonio V. Herrera-Herrera, Javier Herna´ndez-Borges, Chapter 1- New trends in Analytical Sciences -Nanomaterials, in: C.M. Hussain (Ed.), Nanomaterials in Chromatography: Current Trends in Chromatographic Research Technology and Techniques, Elsevier, Amsterdam, (2018) 1 33. [2] Z. Shoujun, M. Qingnan, W. Lei, Z. Junhu, S. Yubin, J. Han, et al., Highly photoluminescent carbon dots for multicolor patterning, sensors, and bioimaging, Angew. Chem. Int. Ed. 52 (2013) 3953 3957. [3] Z. Yang, M. Xu, Y. Liu, F. He, F. Gao, Y. Su, et al., Nitrogen-doped, carbon-rich, highly photoluminescent carbon dots from ammonium citrate, Nanoscale 6 (2014) 1890 1895. [4] A. Jaiswal, S.S. Ghosh, A. Chattopadhyay, One-step synthesis of C-dots by microwave mediated caramelization of poly(ethylene glycol), Chem. Commun. 48 (2012) 407 409. [5] W. Wang, Y. Li, L. Cheng, Z. Cao, W. Liu, Water-soluble and phosphorus-containing carbon dots with strong green fluorescence for cell labeling, J. Mater. Chem. B 2 (2014) 46 48. [6] L. Zhou, Y. Lin, Z. Huang, J. Ren, X. Qu, Carbon nanodots as fluorescence probes for rapid, sensitive, and label-free detection of Hg21 and biothiols in complex matrices, Chem. Commun. 48 (2012) 1147 1149. [7] L. Wang, Y. Bi, J. Gao, Y. Li, H. Ding, L. Ding, Carbon dots based turn-on fluorescent probes for the sensitive determination of glyphosate in environmental water samples, RSC Adv. 6 (2016) 85820 85828. [8] Y. Yang, J. Cui, M. Zheng, C. Hu, S. Tan, Y. Xiao, et al., One-step synthesis of aminofunctionalized fluorescent carbon nanoparticles by hydrothermal carbonization of chitosan, Chem. Commun. 48 (2012) 380 382. [9] V. Sharma, A.K. Saini, S.M. Mobin, Correction: multicolour fluorescent carbon nanoparticle probes for live cell imaging and dual palladium and mercury sensors, J. Mater. Chem. B 4 (2016) 6154. [10] T. Feng, X. Ai, H. Ong, Y. Zhao, Dual-responsive carbon dots for tumor extracellular microenvironment triggered targeting and enhanced anticancer drug delivery, ACS Appl. Mater. Interfaces 8 (2016) 18732 18740. [11] B. Lei, Z. Zhi-Ling, T. Zhi-Quan, Z. Li, L. Cui, L. Yi, et al., Electrochemical tuning of luminescent carbon nanodots: from preparation to luminescence mechanism, Adv. Mater. 23 (2011) 5801 5806. [12] J. Jiang, Y. He, S. Li, H. Cui, Amino acids as the source for producing carbon nanodots: microwave assisted one-step synthesis, intrinsic photoluminescence property and intense chemiluminescence enhancement, Chem. Commun. 48 (2012) 9634 9636.

Carbon nanodots from natural (re)sources: a new perspective on analytical chemistry

23

[13] L. Haitao, H. Xiaodie, K. Zhenhui, H. Hui, L. Yang, L. Jinglin, et al., Water-soluble fluorescent carbon quantum dots and photocatalyst design, Angew. Chem. Int. Ed. 49 (2010) 4430 4434. [14] A. Safavi, F. Sedaghati, H. Shahbaazi, E. Farjami, Facile approach to the synthesis of carbon nanodots and their peroxidase mimetic function in azo dyes degradation, RSC Adv. 2 (2012) 7367 7370. [15] W. Jing, W. Cai-Feng, C. Su, Amphiphilic egg-derived carbon dots: rapid plasma fabrication, pyrolysis process, and multicolor printing patterns, Angew. Chem. Int. Ed. 51 (2012) 9297 9301. [16] B. Chen, F. Li, S. Li, W. Weng, H. Guo, T. Guo, et al., Large scale synthesis of photoluminescent carbon nanodots and their application for bioimaging, Nanoscale 5 (2013) 1967 1971. [17] L. Fei, J. Min-Ho, H.H. Dong, K. Je-Hyung, C. Yong-Hoon, S.T. Seok, Facile synthetic method for pristine graphene quantum dots and graphene oxide quantum dots: origin of blue and green luminescence, Adv. Mater. 25 (2013) 3657 3662. [18] L. Zheng, Y. Chi, Y. Dong, J. Lin, B. Wang, Electrochemiluminescence of watersoluble carbon nanocrystals released electrochemically from graphite, J. Am. Chem. Soc. 131 (2009) 4564 4565. [19] J. Lan, C. Liu, M. Gao, C. Huang, An efficient solid-state synthesis of fluorescent surface carboxylated carbon dots derived from C60 as a label-free probe for iron ions in living cells, Talanta 144 (2015) 93 97. [20] Z. Yang, Z. Li, M. Xu, Y. Ma, J. Zhang, Y. Su, et al., Controllable synthesis of fluorescent carbon dots and their detection application as nanoprobes, Nano-Micro Lett. 5 (2013) 247 259. [21] Z. Ma, H. Ming, H. Huang, Y. Liu, Z. Kang, One-step ultrasonic synthesis of fluorescent N-doped carbon dots from glucose and their visible-light sensitive photocatalytic ability, New J. Chem. 36 (2012) 861 864. [22] L. Haipeng, Y. Tao, M. Chengde, Fluorescent carbon nanoparticles derived from candle soot, Angew. Chem. Int. Ed. 46 (2007) 6473 6475. [23] S. Sahu, B. Behera, T.K. Maiti, S. Mohapatra, Simple one-step synthesis of highly luminescent carbon dots from orange juice: application as excellent bio-imaging agents, Chem. Commun. 48 (2012) 8835 8837. [24] L. Wang, H.S. Zhou, Green synthesis of luminescent nitrogen-doped carbon dots from milk and its imaging application, Anal. Chem. 86 (2014) 8902 8905. [25] P. Hsu, Z. Shih, C. Lee, H. Chang, Synthesis and analytical applications of photoluminescent carbon nanodots, Green Chem. 14 (2012) 917 920. [26] J. Wei, B. Liu, P. Yin, Dual functional carbonaceous nanodots exist in a cup of tea, RSC Adv. 4 (2014) 63414 63419. [27] C. Zhu, J. Zhai, S. Dong, Bifunctional fluorescent carbon nanodots: green synthesis via soy milk and application as metal-free electrocatalysts for oxygen reduction, Chem. Commun. 48 (2012) 9367 9369. [28] Q. Huang, X. Lin, J. Zhu, Q. Tong, Pd-Au@carbon dots nanocomposite: facile synthesis and application as an ultrasensitive electrochemical biosensor for determination of colitoxin DNA in human serum, Biosens. Bioelectron. 94 (2017) 507 512. [29] J. Shen, S. Shang, X. Chen, D. Wang, Y. Cai, Facile synthesis of fluorescence carbon dots from sweet potato for Fe3 1 sensing and cell imaging, Mater. Sci. Eng. C 76 (2017) 856 864.

24

Handbook of Nanomaterials in Analytical Chemistry

[30] B. Yin, J. Deng, X. Peng, Q. Long, J. Zhao, Q. Lu, et al., Green synthesis of carbon dots with down- and up-conversion fluorescent properties for sensitive detection of hypochlorite with a dual-readout assay, Analyst 138 (2013) 6551 6557. [31] X. Yang, Y. Zhuo, S. Zhu, Y. Luo, Y. Feng, Y. Dou, Novel and green synthesis of high-fluorescent carbon dots originated from honey for sensing and imaging, Biosens. Bioelectron. 60 (2014) 292 298. [32] S. Zhao, M. Lan, X. Zhu, H. Xue, T. Ng, X. Meng, et al., Green synthesis of bifunctional fluorescent carbon dots from garlic for cellular imaging and free radical scavenging, ACS Appl. Mater. Interfaces 7 (2015) 17054 17060. [33] H. Xu, X. Yang, G. Li, C. Zhao, X. Liao, Green synthesis of fluorescent carbon dots for selective detection of tartrazine in food samples, J. Agric. Food Chem. 63 (2015) 6707 6714. [34] Y. Feng, D. Zhong, H. Miao, X. Yang, Carbon dots derived from rose flowers for tetracycline sensing, Talanta 140 (2015) 128 133. [35] C. Sun, Y. Zhang, P. Wang, Y. Yang, Y. Wang, J. Xu, et al., Synthesis of nitrogen and sulfur co-doped carbon dots from garlic for selective detection of Fe31, Nanoscale Res. Lett. 11 (2016) 110. [36] Z. Wang, J. Liu, W. Wang, Z. Wei, F. Wang, P. Gong, et al., Photoluminescent carbon quantum dot grafted silica nanoparticles directly synthesized from rice husk biomass, J. Mater. Chem. B 5 (2017) 4679 4689. [37] X. Qin, W. Lu, A. Asiri, A. Al-Youbi, X. Sun, Microwave-assisted rapid green synthesis of photoluminescent carbon nanodots from flour and their applications for sensitive and selective detection of mercury(II) ions, Sens. Actuators B 184 (2013) 156 162. [38] K. Saravanan, N. Kalaiselvi, Nitrogen containing bio-carbon as a potential anode for lithium batteries, Carbon 81 (2015) 43 53. [39] T. Chatzimitakos, A. Kasouni, L. Sygellou, I. Leonardos, A. Troganis, C. Stalikas, Human fingernails as an intriguing precursor for the synthesis of nitrogen and sulfurdoped carbon dots with strong fluorescent properties: analytical and bioimaging applications, Sens. Actuators B 267 (2018) 494 501. [40] A. Cayuela, M. Soriano, C. Carrillo-Carrion, M. Valcarcel, Semiconductor and carbonbased fluorescent nanodots: the need for consistency, Chem. Commun. 52 (2016) 1311 1326. [41] M. Shehab, S. Ebrahim, M. Soliman, Graphene quantum dots prepared from glucose as optical sensor for glucose, J. Lumin. 184 (2017) 110 116. [42] M. Zhou, Z. Zhou, A. Gong, Y. Zhang, Q. Li, Synthesis of highly photoluminescent carbon dots via citric acid and Tris for iron(III) ions sensors and bioimaging, Talanta 143 (2015) 107 113. [43] Z. Xinyue, J. Mingyue, N. Na, C. Zhijun, L. Shujun, L. Shouxin, et al., Natural-product-derived carbon dots: from natural products to functional materials, Chem. Sus. Chem 11 (2018) 11 24. [44] T. Chatzimitakos, A. Kasouni, L. Sygellou, A. Avgeropoulos, A. Troganis, C. Stalikas, Two of a kind but different: luminescent carbon quantum dots from citrus peels for iron and tartrazine sensing and cell imaging, Talanta 175 (2017) 305 312. [45] A. Chatzimarkou, T. Chatzimitakos, A. Kasouni, L. Sygellou, A. Avgeropoulos, C.D. Stalikas, Selective FRET-based sensing of 4-nitrophenol and cell imaging capitalizing on the fluorescent properties of carbon nanodots from apple seeds, Sens. Actuators B 258 (2018) 1152 1160. [46] T. Chatzimitakos, A. Kasouni, A. Troganis, C. Stalikas, Carbonization of human fingernails: toward the sustainable production of multifunctional nitrogen and sulfur codoped

Carbon nanodots from natural (re)sources: a new perspective on analytical chemistry

[47]

[48]

[49]

[50]

[51]

[52]

[53]

[54]

[55]

[56]

[57]

[58]

[59]

[60]

[61]

25

carbon nanodots with highly luminescent probing and cell proliferative/migration properties, ACS Appl. Mater. Interfaces 10 (2018) 16024 16032. N. Wang, Y. Wang, T. Guo, T. Yang, M. Chen, J. Wang, Green preparation of carbon dots with papaya as carbon source for effective fluorescent sensing of iron (III) and Escherichia coli, Biosens. Bioelectron. 85 (2016) 68 75. W. Lu, X. Qin, S. Liu, G. Chang, Y. Zhang, Y. Luo, et al., Economical, green synthesis of fluorescent carbon nanoparticles and their use as probes for sensitive and selective detection of mercury(II) ions, Anal. Chem. 84 (2012) 5351 5357. H. Huang, J. Lv, D. Zhou, N. Bao, Y. Xu, A. Wang, et al., One-pot green synthesis of nitrogen-doped carbon nanoparticles as fluorescent probes for mercury ions, RSC Adv. 3 (2013) 21691 21696. L. Wang, Y. Bi, J. Hou, H. Li, Y. Xu, B. Wang, et al., Facile, green and clean one-step synthesis of carbon dots from wool: application as a sensor for glyphosate detection based on the inner filter effect, Talanta 160 (2016) 268 275. R. Bandi, B. Gangapuram, R. Dadigala, R. Eslavath, S. Singh, V. Guttena, Facile and green synthesis of fluorescent carbon dots from onion waste and their potential applications as sensor and multicolour imaging agents, RSC Adv. 6 (2016) 28633 28639. Y. Hu, L. Zhang, X. Li, R. Liu, L. Lin, S. Zhao, Green preparation of S and N codoped carbon dots from water chestnut and onion as well as their use as an off on fluorescent probe for the quantification and imaging of Coenzyme A, ACS Sustain. Chem. Eng 5 (2017) 4992 5000. A. Su, D. Wang, X. Shu, Q. Zhong, Y. Chen, J. Liu, et al., Synthesis of fluorescent carbon quantum dots from dried lemon peel for determination of carmine in drinks, Chem. Res. Chin. Univ. 34 (2018) 164 168. R. Liu, J. Zhang, M. Gao, Z. Li, J. Chen, D. Wu, et al., A facile microwavehydrothermal approach towards highly photoluminescent carbon dots from goose feathers, RSC Adv. 5 (2015) 4428 4433. Z. Zhang, W. Sun, P. Wu, Highly photoluminescent carbon dots derived from egg white: facile and green synthesis, photoluminescence properties, and multiple applications, ACS Sustain. Chem. Eng. 3 (2015) 1412 1418. Y. Xu, D. Li, M. Liu, F. Niu, J. Liu, E. Wang, Enhanced-quantum yield sulfur/nitrogen co-doped fluorescent carbon nanodots produced from biomass Enteromorpha prolifera: synthesis, posttreatment, applications and mechanism study, Sci. Rep. 7 (2017) 4499. J. He, B. Lei, H. Zhang, M. Zheng, H. Dong, J. Zhuang, et al., Using hydrogen peroxide to mediate through a one-step hydrothermal method for the fast and green synthesis of N-CDs, RSC Adv. 5 (2015) 95744 95749. L. Fang, Q. Xu, X. Zheng, W. Zhang, J. Zheng, M. Wu, et al., Soy flour-derived carbon dots: facile preparation, fluorescence enhancement, and sensitive Fe31 detection, J. Nanopart. Res. 18 (2016) 224. T. Edison, R. Atchudan, J. Shim, S. Kalimuthu, B. Ahn, Y. Lee, Turn-off fluorescence sensor for the detection of ferric ion in water using green synthesized N-doped carbon dots and its bio-imaging, J. Photochem. Photobiol. B 158 (2016) 235 242. G. Gedda, C. Lee, Y. Lin, H. Wu, Green synthesis of carbon dots from prawn shells for highly selective and sensitive detection of copper ions, Sens. Actuators B 224 (2016) 396 403. X. Teng, C. Ma, C. Ge, M. Yan, J. Yang, Y. Zhang, et al., Green synthesis of nitrogendoped carbon dots from konjac flour with “off-on” fluorescence by Fe3 1 and l-lysine for bioimaging, J. Mater. Chem. B 2 (2014) 4631 4639.

26

Handbook of Nanomaterials in Analytical Chemistry

[62] M. Xue, M. Zou, J. Zhao, Z. Zhan, S. Zhao, Green preparation of fluorescent carbon dots from lychee seeds and their application for the selective detection of methylene blue and imaging in living cells, J. Mater. Chem. B 3 (2015) 6783 6789. [63] L. Zhu, Y. Yin, C. Wang, S. Chen, Plant leaf-derived fluorescent carbon dots for sensing, patterning and coding, J. Mater. Chem. C 1 (2013) 4925 4932. [64] S. Majumdar, U. Baruah, G. Majumdar, D. Thakur, D. Chowdhury, Paper carbon dot based fluorescence sensor for distinction of organic and inorganic sulphur in analytes, RSC Adv. 6 (2016) 57327 57334. [65] S. Wee, Y. Ng, S. Ng, Synthesis of fluorescent carbon dots via simple acid hydrolysis of bovine serum albumin and its potential as sensitive sensing probe for lead (II) ions, Talanta 116 (2013) 71 76. [66] A. Tyagi, K. Tripathi, N. Singh, S. Choudhary, R. Gupta, Green synthesis of carbon quantum dots from lemon peel waste: applications in sensing and photocatalysis, RSC Adv. 6 (2016) 72423 72432. [67] A. Kumar, A. Chowdhuri, D. Laha, T. Mahto, P. Karmakar, S. Sahu, Green synthesis of carbon dots from Ocimum sanctum for effective fluorescent sensing of Pb21 ions and live cell imaging, Sens. Actuators B 242 (2017) 679 686. [68] G. Huang, X. Chen, C. Wang, H. Zheng, Z. Huang, D. Chen, et al., Photoluminescent carbon dots derived from sugarcane molasses: synthesis, properties, and applications, RSC Adv. 7 (2017) 47840 47847. [69] Y. Wang, W. Wu, M. Wu, H. Sun, H. Xie, C. Hu, et al., Yellow-visual fluorescent carbon quantum dots from petroleum coke for the efficient detection of Cu21 ions, New Carbon Mater. 30 (2015) 550 559. [70] Y. Xu, C. Tang, H. Huang, C. Sun, Y. Zhang, Q. Ye, et al., Green synthesis of fluorescent carbon quantum dots for detection of Hg21, Chin. Anal. Chem. 42 (2014) 1252 1258. [71] H. Thi, V. Pham, V. Nhu, N. Hung, T. Dinh, N. Thi, et al., Luminescence of lemonderived carbon quantum dot and its potential application in luminescent probe for detection of Mo61 ions, Luminescence 33 (2018) 545 551. [72] Z. Li, Y. Ni, S. Kokot, A new fluorescent nitrogen-doped carbon dot system modified by the fluorophore-labeled ssDNA for the analysis of 6-mercaptopurine and Hg (II), Biosens. Bioelectron. 74 (2015) 91 97. [73] S. Vandarkuzhali, V. Jeyalakshmi, G. Sivaraman, S. Singaravadivel, K. Krishnamurthy, B. Viswanathan, Highly fluorescent carbon dots from pseudo-stem of banana plant: applications as nanosensor and bio-imaging agents, Sens. Actuators B 252 (2017) 894 900. [74] K. Tripathi, A. Sonker, S. Sonkar, S. Sarkar, Pollutant soot of diesel engine exhaust transformed to carbon dots for multicoloured imaging of E. coli and sensing cholesterol, RSC Adv. 4 (2014) 30100 30107. [75] D. Gu, S. Shang, Q. Yu, J. Shen, Green synthesis of nitrogen-doped carbon dots from lotus root for Hg(II) ions detection and cell imaging, Appl. Surf. Sci. 390 (2016) 38 42. [76] S. Liu, J. Tian, L. Wang, Y. Zhang, X. Qin, Y. Luo, et al., Hydrothermal treatment of grass: a low-cost, green route to nitrogen-doped, carbon-rich, photoluminescent polymer nanodots as an effective fluorescent sensing platform for label-free detection of Cu (II) ions, Adv. Mater. 24 (2012) 2037 2041. [77] W. Liu, H. Diao, H. Chang, H. Wang, T. Li, W. Wei, Green synthesis of carbon dots from rose-heart radish and application for Fe31 detection and cell imaging, Sens. Actuators B 241 (2017) 190 198.

Carbon nanodots from natural (re)sources: a new perspective on analytical chemistry

27

[78] B. Manoj, A. Raj, G. Chirayil, Tunable direct band gap photoluminescent organic semiconducting nanoparticles from lignite, Sci. Rep. 7 (2017) 18012. [79] J. Essner, C. Laber, S. Ravula, L. Polo-Parada, G. Baker, Pee-dots: biocompatible fluorescent carbon dots derived from the upcycling of urine, Green Chem. 18 (2016) 243 250. [80] B. Lin, Y. Yan, M. Guo, Y. Cao, Y. Yu, T. Zhang, et al., Modification-free carbon dots as turn-on fluorescence probe for detection of organophosphorus pesticides, Food Chem. 245 (2018) 1176 1182. [81] Q. Xu, Y. Liu, C. Gao, J. Wei, H. Zhou, Y. Chen, et al., Synthesis, mechanistic investigation, and application of photoluminescent sulfur and nitrogen co-doped carbon dots, J. Mater. Chem. C 3 (2015) 9885 9893. [82] V. Sharma, P. Tiwari, S. Mobin, Sustainable carbon-dots: recent advances in green carbon dots for sensing and bioimaging, J. Mater. Chem. B 5 (2017) 8904 8924. [83] M. Amjadi, T. Hallaj, M. Mayan, Green synthesis of nitrogen-doped carbon dots from lentil and its application for colorimetric determination of thioridazine hydrochloride, RSC Adv. 6 (2016) 104467 104473. [84] M. Yuan, R. Zhong, H. Gao, W. Li, X. Yun, J. Liu, et al., One-step, green, and economic synthesis of water-soluble photoluminescent carbon dots by hydrothermal treatment of wheat straw, and their bio-applications in labeling, imaging, and sensing, Appl. Surf. Sci. 355 (2015) 1136 1144. [85] T. Pal, S. Mohiyuddin, G. Packirisamy, Facile and green synthesis of multicolor fluorescence carbon dots from curcumin: in vitro and in vivo bioimaging and other applications, ACS Omega 3 (2018) 831 843. [86] R. Yang, X. Guo, L. Jia, Y. Zhang, Z. Zhao, F. Lonshakov, Green preparation of carbon dots with mangosteen pulp for the selective detection of Fe31 ions and cell imaging, Appl. Surf. Sci. 423 (2017) 426 432. [87] M. Farshbaf, S. Davaran, F. Rahimi, N. Annabi, R. Salehi, A. Akbarzadeh, Carbon quantum dots: recent progresses on synthesis, surface modification and applications, Artif. Cells Nanomed. Biotechnol 46 (2017) 1331 1348. [88] R. Zhang, W. Chen, Nitrogen-doped carbon quantum dots: facile synthesis and application as a “turn-off” fluorescent probe for detection of Hg21 ions, Biosens. Bioelectron. 55 (2014) 83 90. [89] C. Soumen, L. Dipranjan, P. Arindam, R. Angshuman, K. Parimal, S. Kumar, Synthesis of highly fluorescent nitrogen and phosphorus doped carbon dots for the detection of Fe31 ions in cancer cells, Luminescence 31 (2016) 81 87. [90] S. Sharma, A. Umar, S. Sood, S. Mehta, S. Kansal, Photoluminescent C-dots: an overview on the recent development in the synthesis, physiochemical properties and potential applications, J. Alloys Compd. 748 (2018) 818 853. [91] H. Liu, X. Zhao, F. Wang, Y. Wang, L. Guo, J. Mei, et al., High-efficient excitationindependent blue luminescent carbon dots, Nanoscale Res. Lett. 12 (2017) 399. [92] S. Maiti, S. Kundu, C. Roy, T. Das, A. Saha, Synthesis of excitation independent highly luminescent graphene quantum dots through perchloric acid oxidation, Langmuir 33 (2017) 14634 14642. [93] D. Chen, H. Gao, X. Chen, G. Fang, S. Yuan, Y. Yuan, Excitation-independent dualcolor carbon dots: surface-state controlling and solid-state lighting, ACS Photon. 4 (2017) 2352 2358. [94] J. Zhang, A. Niu, J. Li, J. Fu, Q. Xu, D. Pei, In vivo characterization of hair and skin derived carbon quantum dots with high quantum yield as long-term bioprobes in zebrafish, Sci. Rep. 6 (2016) 37860.

28

Handbook of Nanomaterials in Analytical Chemistry

[95] P. Suvarnaphaet, C. Tiwary, J. Wetcharungsri, S. Porntheeraphat, R. Hoonsawat, P. Ajayan, et al., Blue photoluminescent carbon nanodots from limeade, Mater. Sci. Eng. C 69 (2016) 914 921. [96] J. Shi, G. Ni, J. Tu, X. Jin, J. Peng, Green synthesis of fluorescent carbon dots for sensitive detection of Fe2 1 and hydrogen peroxide, J. Nanoparticle Res. 19 (2017) 209. [97] P. Zuo, X. Lu, Z. Sun, Y. Guo, H. He, A review on syntheses, properties, characterization and bioanalytical applications of fluorescent carbon dots, Microchim. Acta 183 (2016) 519 542. [98] W. Wang, J. Xia, J. Feng, M. He, M. Chen, J. Wang, Green preparation of carbon dots for intracellular pH sensing and multicolor live cell imaging, J. Mater. Chem. B 4 (2016) 7130 7137. [99] X. Sun, Y. Lei, Fluorescent carbon dots and their sensing applications, TrAC Trends Anal. Chem. 89 (2017) 163 180. [100] A. Sachdev, P. Gopinath, Green synthesis of multifunctional carbon dots from coriander leaves and their potential application as antioxidants, sensors and bioimaging agents, Analyst 140 (2015) 4260 4269. [101] Q. Liang, Y. Wang, F. Lin, M. Jiang, P. Li, B. Huang, A facile microwavehydrothermal synthesis of fluorescent carbon quantum dots from bamboo tar and their application, Anal. Methods 9 (2017) 3675 3681. [102] F. Zu, F. Yan, Z. Bai, J. Xu, Y. Wang, Y. Huang, et al., The quenching of the fluorescence of carbon dots: a review on mechanisms and applications, Microchim. Acta 184 (2017) 1899 1914. [103] T. Larsson, M. Wedborg, D. Turner, Correction of inner-filter effect in fluorescence excitation-emission matrix spectrometry using Raman scatter, Anal. Chim. Acta 583 (2007) 357 363.

Modern age of analytical chemistry: nanomaterials

2

Sibel Bu¨yu¨ktiryaki1, Ru¨stem Kec¸ili1 and Chaudhery Mustansar Hussain2 1 Yunus Emre Vocational School of Health Services, Department of Medical Services and Techniques, Anadolu University, Eski¸sehir, Turkey, 2Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, NJ, United States

2.1

Introduction

Analytical chemistry has gained great importance since the intensive studies related to chemistry. The amount of substances in the sample as well as the questions of which elements and chemicals are present in the sample accelerate the development of analytical chemistry. Analytical chemistry has provided important variation in research (R), development (D), and transfer of analytical information and technology (T) in the 20th and 21st centuries. The fundamentals of analytical chemistry have already been established before and now continue to make significant contributions to all sciences through the use of these fundamentals. Nanomaterials are being investigated extensively in many areas because of their interesting chemical and physical properties (such as size, surface area, conductivity, magnetism, mechanical strength, thermal, and light absorption and emission). In addition to these unique physical properties, it has been ensured that they have significantly improved performance and new applications between physics, chemistry, biology, engineering, and computer science with their remarkable recognition capabilities. In addition to high mechanical strength and low weight, many of the exceptional properties of nanomaterials depend on surface properties (roughness, surface area, energy, and electron distributions) that allow for enhanced interaction with many biological molecules. These interactions depend not only on the production method but also on the size and specific geometry of the nanoparticles. These properties can affect the stability and selectivity of nanomaterials with the facility to create hydrogen bonds, dispersion forces, and hydrophobic interactions. These distinctive properties of nanomaterials have been used to improve innovative applications in sample preparation, separation, and detection in analytical chemistry. To predict the future of analytical chemistry with nanomaterials, the development of both should be examined over the years. In this chapter, the development of nanotechnology and analytical chemistry over the years, different classifications of nanotechnology, and the usage of nanomaterials as tools and analytes in different applications are described.

Handbook of Nanomaterials in Analytical Chemistry. DOI: https://doi.org/10.1016/B978-0-12-816699-4.00002-5 Copyright © 2020 Elsevier Inc. All rights reserved.

30

2.2

Handbook of Nanomaterials in Analytical Chemistry

History of analytical chemistry

As we now understand, modern chemistry started with chemical revolution of the 18th century but chemical processes had been in use long before that. Analytical chemistry and trade could not go beyond the barter system without the weight and measure system invention. The term “analyst” was first used by Robert Boyle (1627 91) in the book “The Sceptical Chymist” in 1661, and then gravimetric analysis was invented in the 17th century by Friedrich Hoffmann (1660 1742). Later, stoichiometric concepts were founded by Joens Jakob Berzelius (1779 1848) and qualitative and quantitative analysis was introduced by Torben Bergman (1735 84). The law of conservation of mass was invented by Antoine Lavoisier (1743 94) and he also gained the title as the father of quantitative analysis. Talbot (1843), and later Kirchhoff and Bunsen examined the emission spectra of many elements in the flames and made important spectroscopic investigations and then spectroscopy was presented as one of the efficient analytical tools. In 1862, C.R. Fresenius stated that chemical analysis was directly based on general chemistry and could not be applied without knowledge. In addition, Fresenius stated that the analysis should be regarded as one of the main pillars of all other scientific structures, as well as being important for all branches of chemistry. “On the Equilibrium of Heterogeneous Substance” study, which is related to the free energy, phase rule, chemical potential, and chemical equilibrium, known as the basic principles of the analytical chemistry, was published in 1876 by W. Gibbs. And then another important and effective study on the scientific basis of analytical chemistry was published in 1894 by Wilhelm Ostwald. He tried to make the theoretical explanations of analytical processes such as equilibrium constants and strongly pointed out the role of analytical chemistry in the progression of chemistry and also worked on the development of analytical chemistry using the fundamentals of physical chemistry. The study related to the catalysis, fundamental principles governing chemical equilibrium, and reaction rates was performed in 1909 by Wilhelm Ostwald and he was awarded the Nobel Prize in chemistry for this study. Analytical chemistry was identified by Ostwald as the art of separation, recognition of different substances, and determination of the content of the sample. In 1973, I.M. Kolthoff also stated his observations on the importance of physical, chemical, and biophysical chemistry in the application of analytical chemistry with a similar approach to Ostwald. Kolthoff, described as the father of modern analytical chemistry, stated that analytical chemistry will remain as a scientific discipline as long as new products are being produced in the industry, as long as there are unresolved problems in chemistry, and as long as chemistry is an integral part of the natural sciences. Another pioneer is Walther Nernst, known as the father of modern electroanalytical chemistry. The Nernst equation led to the development of other techniques such as potentiometry, potentiometric titrations, voltammetry, amperometric titrations, electroseparations, coulometry, and polarography [1 3]. Since those times, analytical chemistry has continued to develop as a branch of chemistry

Modern age of analytical chemistry: nanomaterials

31

science for industry, agriculture, forensics, medicine, health, environment, engineering, and all applied science. Analytical chemistry is a discipline that utilizes instruments and methods for separation, identification, and quantification of materials. It develops and applies methods, tools, and procedures to gain deeper knowledge about composition (form, homogeneity, quality, concentration, and the pattern of chemical bonding) and structure (spatial arrangement of atoms or molecules) of substances and materials by expending less material, time, effort, and money. It examines and processes the methods, rules, and laws for analytical cognition, including rules for the chemical interpretation of analytical measurement. Analytical chemistry can be defined as follows: “Analytical chemistry is a metrological scientific discipline that develops, optimizes, and applies methods, uses instruments and strategies to obtain information on the composition and nature (physical, biological, biochemical, and chemical) of matter and also in order to solve scientific, technical, and social problems.” Qualitative, quantitative, and structural chemical information obtained by analytical chemistry provides a three-dimensional representation of the substance. It is the task of an analytical chemist to continuously develop methodologies or use developed instrumental analyzers to achieve the correct result in a shorter time or more easily and more economically. When the same result is achieved by using completely different analytical methods, the probability of systematic measurement errors is very low and the analytical result can be considered correct. Good laboratory practice should be developed to check the reliability of the results produced using chemometry, certified standard reference materials, and another methods [4 7]. Analytical features are one of the quality indicators for the various systems and outputs of (bio)chemical processes that allow analytical processes and results to be compared and verified. Accuracy (related to traceability and uncertainty), reliability, and representability are the top analytical features of analytical results. Precision, robustness, sensitivity, and selectivity are the basic analytical features of analytical processes and strengthen for top analytical features of analytical results. Analytical processes are required to be quick and cheap. Speed, cost-effectiveness, and person-related factors are the productivity-related features of analytical processes [8]. Instrumental analysis prevails in modern analytical chemistry. Thanks to the advances in microelectronics and computer technology, analytical chemistry has undergone very important developments in automation capabilities, miniaturization, high sensitivities, improved resolution power, and analysis capability. In recent years, highly developed nanoscopic imaging methods, which have super-resolution techniques, hyperspectral analysis, and hyphenated instruments, have appeared. Although conventional imaging devices such as optical microscopes were previously used, advanced imaging devices are now used, such as transmission electron microscopy (TEM), scanning electron microscopy, and scanning tunneling microscopy. During the last decade, the scientific and technological studies have changed from the macroscopic to the nanoscopic size level. As in many other areas, analytical chemistry has been heavily influenced by nanoscience and nanotechnology.

32

2.3

Handbook of Nanomaterials in Analytical Chemistry

History of nanotechnology

The nanoscience and nanotechnology fields are currently evolving and they will proceed developing over the coming years because of numerous applications and great advantages in a wide range of disciplines [9 16]. Nanotechnology involves physics, chemistry, biology, materials science, energy, medicine, textile, agrifoods, and mechanical, electrical, and chemical engineering. Nanoscience is an interdisciplinary study related to the handling of materials at atomic, molecular, and macromolecular scales, where physicochemical properties diverge importantly from those at a larger scale. Nanoscience is the study of particles at a very small scale in the range of 1 100 nm. Nanotechnology is related to the progressions in nanoscience and its interests with the design, characterization, fabrication, and utilization of particles, structures, devices, and systems by controlling the shape and size [17]. According to a study published in Science at 2005 by Hassan, nanotechnology will be transforming and revolutionary technology like the steam machine in the 19th century, electricity and the Internet in the 20th century, and the internet in the 20th century [18]. First in 1959, Richard Feynman foreseeingly said that “There’s plenty of room at the bottom,” at an annual meeting of the American Physical Society in Caltech and he published an article related to his speech 1 year later in Caltech’s Engineering and Science [19]. He emphasized the possibility of managing and controlling things on a small scale. Feynman’s view of miniaturization is now accepted as the starting point of nanotechnology. In 1974, the term nanotechnology was first used by Norio Taniguchi to describe semiconductor processes, such as thin film deposition, and his definition still remains a fundamental expression. He defined the nanotechnology as “Nano-technology mainly consists of the processing of separation, consolidation, and deformation of materials by one atom or one molecule.” In 1986, about 30 years after Feynman’s talk, K. Eric Drexler published his book titled “Engines of Creation” related to molecular nanotechnology and also used the term nanotechnology [20]. Thus the researchers began to reduce their work to the molecular level instead of the macroscopic system concepts in order to further develop the nanotechnology production systems.

2.4

Classification of nanomaterials and application of nanomaterials as tools and analytes

Nanomaterials can be classified according to their origin, nature, dimension, and homogeneity. According to their origin, nanomaterials can be classified as natural, incidental or anthropogenic, and engineered [by using physical (top-down) and chemical (bottom-up) approach]. Nanomaterials can be classified as organic (carbon nanotubes, graphenes, molecularly imprinted polymers, etc.), inorganic (metal nanoparticles, metal oxide nanoparticles, quantum dots, etc.), and hybrid as their nature. Nanomaterials can be classified as organic (carbon nanotubes, graphenes, molecularly imprinted polymers, etc.), inorganic (metal nanoparticles, metal oxide

Modern age of analytical chemistry: nanomaterials

33

nanoparticles, quantum dots, etc.), and hybrids according to their nature. Nanomaterials can be homogeneous or heterogeneous in structure. According to the number of dimensions, nanomaterials also can be classified as zero-dimensional nanostructures (quantum dots, carbon dots, metallic nanoparticles, etc.), onedimensional nanostructures (nanofibers, nanowires, nanorods, carbon nanotubes, etc.), two-dimensional nanomaterials (thin films, nanosheets, quantum wells, nanocoatings, nanoplates, etc.), and three-dimensional nanomaterials (nanocomposites, nanostructured materials, etc.). When all dimensions are in a few nanometers, they are called zero-dimensional nanomaterials. These zero-dimensional nanomaterials can be used in the detection of antibody [21] and also can be used in separation of biomolecules [22]. When only one dimension is outside the nanometer scale, they are called as one-dimensional nanomaterials. They can be used in filtration applications [23]. Mihail Roco in the US National Nanotechnology Initiative has classified the nanotechnology products with a focus on production methods and research as four generations. Passive nanostructures (nanostructured coatings, nanoparticles dispersions, and bulk materials (metals, polymers, and ceramics)) are classified as firstgeneration products, they were started to be used in about 2001 and focused on the synthesis and control of nanoscale processes as well as measuring tools. Active nanostructures (transistors, amplifiers, targeted drugs and chemicals, actuators, and adaptive structures) are classified as second-generation products, they were started to be used in about 2005 and focused on new devices and production of device system. Nanobiosensors, tools for medicine and food systems, instrumentation, and nano production of three-dimensional nanoscale, production of remote measurement systems, and their societal effects are the main research areas for the secondgeneration products. Three-dimensional nanosystems and systems of nanosystems with several synthesis and assembling techniques (bioassembling, networking at the nanoscale and multiscale structure) are classified as third-generation products, they were started to be used in about 2010 and focused on heterogeneous nanostructures and supramolecular system. Multiscale self-assembling, artificial tissues and sensorial systems, quantum interactions within nanoscale systems, nanostructured photonic devices, scalable plasmonic devices, nanoscale electromechanical systems, and targeted cell therapy with nanodevices are the main research areas for the thirdgeneration products. Heterogeneous molecular nanosystems are classified as fourthgeneration products, they were started to be used in about 2015 and focused on each molecule within the nanosystem. Each molecule has a particular shape and performs a different function. Atomic manipulation for design of molecules and supramolecular systems, dynamics of a single molecule, molecular machines, design of large heterogeneous molecular systems, nanosystem biology for healthcare and convergence of nano-bio-info-cognitive domains are the main research areas for the fourth-generation products [24]. It is now time to start deeper and more comprehensive studies in heterogeneous molecular nanosystems and nanosystem systems. Nanotechnology and nanoscience tools enhance analytical properties by opening up new analysis opportunities. Therefore, it is important for them to be involved in

34

Handbook of Nanomaterials in Analytical Chemistry

Figure 2.1 Schematic representation of the usage of nanomaterials in the analytical procedures. SPE, Solid-phase extraction; CPE, cloud-phase extraction.

analytical sciences to study, research, and develop. Thanks to their advantageous properties, the nanomaterials can be used as a tool at different stages of the analytical process, including sample collection, sample preparation, separation, and detection (Fig. 2.1). There may be different uses according to the stage of their analytical procedures [sample collection, sample preparation, separation techniques (Gas Chromatography (GC), High Performance Liquid Chromatography (HPLC), Capillary Electrophoresis (CE)), detection, and data handling]. Different nanomaterials such as carbon nanotubes [25], graphenes [26,27], metal nanoparticles, metal oxide nanoparticles, magnetic nanomaterials [22,27], hybrid nanomaterials [28], and molecularly imprinted polymers [14] as composite nanomaterials can be used in sample preparation. Sample preparation is one of the important factor for determination of molecules in the complex matrix environment. For this purpose, preconcentration, solid-phase extraction, solid-phase microextraction, cloud-point extraction (CPE), dispersive liquid liquid extraction can be used [29,30]. The preconcentration is a technique in which the desired analyte concentration is determined at a lower concentration to obtain a higher sensitivity for the analysis. Numerous studies have been carried out to generate preconcentration methods using nanomaterials as adsorbents [31 33]. Nanoparticles have high adsorption capacity for analyte because of they have high surface area to volume ratios. Nanoparticles can be used as preconcentration platform before the analysis of biomolecules via various analytical procedures, also used as an affinity probe for the efficient protein identification by matrix-assisted laser desorption ionization time-of-flight mass spectrometry and thus providing a specific enrichment of the biomolecules [34 36]. Another interesting study related to CPE by Pourreza et al. [37] developed a useful CPE method for the colorimetric detection of citrate in lemon juice and pharmaceutical samples by using curcumin nanoparticles. In this

Modern age of analytical chemistry: nanomaterials

35

study, citrate ions were determined selectivley in fruit juice and pharmaceutical samples. A mixture of citrate solution, curcumin nanoparticles, Triton X-100, NaCl, and Fe31 solutions were prepared and heated in a water bath at 80 C for 50 min and then this cloudy solution was cooled in an ice-bath for 5 min. After the cloudy solution was centrifuged, the surfactant-rich phase was separated and analyzed by UV visible (vis) spectrophotometer. Nanaomaterials can be used as new stationary phases, pseudostationary phases or supports to improve the efficiency, selectivity, and resolution in separation methods. Thanks to the increased surface area and adsorption properties in touch with the soluble materials, the selectivity, and separation efficiency increase. In particular, carbon-based nanomaterials, such as carbon nanotubes, grapheme, and fullerenes, and also metal-organic frameworks and metal oxide nanomaterials have found a wide range of applications as stationary phases in chromatographic (LC or GC columns) [25,38,39] and electrophoretic (capillary electrophoresis, chip-based capillary electrophoresis techniques, capillary electrochromatography) methods with different detection systems [40 42]. Zhang and colleagues prepared the column with titanium oxide nanoparticles and polydopamine film and then used that column for the separation of β-lactoglobulin and glycoisoforms of ovalbumin in egg white by using Capillary electrochromatography (CEC) [43]. There are many studies using nanoparticles as a column material for the separation and determination of polyaromatic hydrocarbons in the literature [44,45]. There is still a need for the development of new column materials using nanomaterials to effective and selective separation of substances from complex samples. New trends are focused on the development of faster, easier, and more costeffective nanosensors for the analysis and monitoring of molecules. In this context, nanomaterials provide a major breakthrough with the development of different nanoprobes for the detection of molecules in a wide variety of samples. Owing to the luminescence properties of the semiconductor quantum dots and the plasmon resonance of metallic nanoparticles, they are widely used for the development of optical nanosensors. As a result of the use of nanomaterials as nanosensors, the molecules can be determined at lower concentrations [46]. When nanoscience and nanotechnology are included in the field of analytical science, various possibilities are given, as suggested by Vaca´rcel et al. [47,48] (as shown in Fig. 2.2). As can be seen in Fig. 2.2, nanoparticles can be used in analytical processes in two different ways as tools and analytes. When the size of the material approaches the nanoscale, it dissolves better, the sorption properties significantly increase and their physicochemical properties change greatly. Analytical chemistry can contribute important information on the characterization of nanomaterials for the development of synthesis methods and properties of these nanomaterials. In addition, the analysis of nanomaterials in different environments provides information about behavior, future, environmental health, and socioeconomic results. Owing to the increasing use of engineering nanoparticles used in different industries and research on environmental and consumer risks, the need for the analysis of nanomaterials has increased in recent years. For the analysis of nanomaterials, a large number of chemical and physical parameters can be studied, including

36

Handbook of Nanomaterials in Analytical Chemistry

Figure 2.2 The two classical components of analytical nanoscience and nanotechnology, nanoparticles as analytes or as tools.

particle size, size distribution, shape, agglomeration, composition, structure, concentration, surface properties, and presence of any surface coating or contamination. Surface, porosity, and size of nanomaterials can be determined by using TEM, atomic force microscopy and dynamic light scattering. Concentration of nanomaterials can be determined by using inductively coupled plasma mass spectrometry (ICP-MS), liquid chromatography mass spectrometry (LC-MS), ultraviolet visible spectroscopy (UV Vis), and fluorescence spectroscopy. Nanochip liquid chromatography is one of the nanometric analytical systems. The nanometric analytical systems are analytical systems that take advantage of having a nanometric flow dimension. The basics of this system are not based on the physicochemical, physical, and chemical properties of nanomaterials. There is a tendency for miniaturization in nanometric analytical systems. In contrast to the nanometric analytical systems, nanotechnological analytical systems utilize the physicochemical properties of nanomaterials. Microelectromechanical systems are examples of nanotechnological analytical systems. Analytical nanosystems combine both of them (nanometric analytical systems and nanotechnological analytical systems). Lab-on-a-chip systems are examples of analytical nanosystems [49]. In terms of the ease of use, size, and cost, lab-on-a-chip systems have many advantages [50].

2.5

Conclusions

Analytical nanoscience and nanotechnology are a subdiscipline that maintains the overall exponential growth of almost all nanoscience and nanotechnology branches. The remarkable physicochemical properties of nanostructured materials make a significant contribution to this growth. Nanomaterials have important roles in various techniques to enhance sensitivity, enhance selectivity, simplify analytical procedures, and improve analytical efficiency. Nanomaterials have a bright future in

Modern age of analytical chemistry: nanomaterials

37

many areas. At the same time, it should be remembered that the application of nanomaterials is still at an early stage and there are still problems or difficulties associated with many analyses. In terms of analytical nanoscience and nanotechnology, the use of nanomaterials as analytical tools is the most advanced field. More than half of the reported studies are related to the use of nanoparticles as analytical tools. As the increasing importance of the characterization of nanomaterials and the development of new tools based on nanotechnological approaches, the balance is expected to change in the near future.

References [1] M.I. Karayannis, C.E. Efstathiou, Significant steps in the evolution of analytical chemistry—is the today’s analytical chemistry only chemistry? Talanta 102 (2012) 7 15. Available from: https://doi.org/10.1016/j.talanta.2012.06.003. [2] K.L. Lindblom, Izaak Maurits Kolthoff and modern analytical chemistry, Am. Chem. Soc. Natl. Hist. Chem. Landmarks (2014). Available from: http://www.acs.org/content/ acs/en/education/whatischemistry/landmarks/kolthoff-analytical-chemistry.html. [3] H. Gu¨nzler, A. Williams, Handbook of analytical techniques. ,https://doi.org/10.1002/ 9783527618323., 2008. [4] K. Cammann, Analytical chemistry today’s definition and interpretation, Fresenius. J. Anal. Chem. 343 (1992) 812 813. Available from: https://doi.org/10.1007/BF00328560. [5] M. Valcarcel, Analytical chemistry today’s definition and interpretation, Fresenius. J. Anal. Chem. 343 (1992) 814 816. Available from: https://doi.org/10.1007/BF00328561. [6] A.M. Zuckerman, Analytical chemistry today’s definition and interpretation, Fresenius. J. Anal. Chem. 343 (1992) 817 818. Available from: https://doi.org/ 10.1007/BF00328562. ´ .I. Lo´pez-Lorente, M.A ´ . Lo´pez-Jime´nez, Foundations of analyti[7] M. Valca´rcel Cases, A cal chemistry, Springer International Publishing, Cham, Switzerland, 2017. Available from: https://doi.org/10.1007/978-3-319-62872-1. [8] I.S. Krull, Analytical chemistry, IntechOpen, Rijeka, Croatia, 2012, pp. 357 363. Available from: https://doi.org/10.5772/50497. [9] R. Kec¸ili, S. Bu¨yu¨ktiryaki, C.M. Hussain, Advancement in bioanalytical science through nanotechnology: past, present and future, TrAC Trends Anal. Chem. 110 (2019) 259 276. Available from: https://doi.org/10.1016/j.trac.2018.11.012. ´ . Rodrı´guez[10] B. Socas-Rodrı´guez, J. Gonza´lez-Sa´lamo, J. Herna´ndez-Borges, M.A Delgado, Recent applications of nanomaterials in food safety, TrAC Trends Anal. Chem. 96 (2017) 172 200. Available from: https://doi.org/10.1016/j.trac.2017.07.002. [11] R. Viswambari Devi, M. Doble, R.S. Verma, Nanomaterials for early detection of cancer biomarker with special emphasis on gold nanoparticles in immunoassays/sensors, Biosens. Bioelectron. 68 (2015) 688 698. Available from: https://doi.org/10.1016/j. bios.2015.01.066. [12] X. Ge, A.M. Asiri, D. Du, W. Wen, S. Wang, Y. Lin, Nanomaterial-enhanced paperbased biosensors, TrAC Trends Anal. Chem. 58 (2014) 31 39. Available from: https:// doi.org/10.1016/j.trac.2014.03.008.

38

Handbook of Nanomaterials in Analytical Chemistry

[13] W.C. Tseng, K.C. Hsu, C.S. Shiea, Y.L. Huang, Recent trends in nanomaterial-based microanalytical systems for the speciation of trace elements: a critical review, Anal. Chim. Acta. 884 (2015) 1 18. Available from: https://doi.org/10.1016/j.aca.2015.02.041. [14] R. Kec¸ili, C.M. Hussain, Recent progress of imprinted nanomaterials in analytical chemistry, Int. J. Anal. Chem. 2018 (2018) 1 18. Available from: https://doi.org/ 10.1155/2018/8503853. [15] J. Wang, Q. Liu, Y. Liang, G. Jiang, Recent progress in application of carbon nanomaterials in laser desorption/ionization mass spectrometry, Anal. Bioanal. Chem. 408 (2016) 2861 2873. Available from: https://doi.org/10.1007/s00216-015-9255-4. ´ . Rı´os, M. Zougagh, Recent advances in magnetic nanomaterials for improving ana[16] A lytical processes, TrAC Trends Anal. Chem. 84 (2016) 72 83. Available from: https:// doi.org/10.1016/j.trac.2016.03.001. [17] Nanoscience and Nanotechnologies: Opportunities and Uncertainties, The Royal Society & The Royal Academy of Engineering, London, UK. ,https://doi.org/10.1007/ s00234-004-1255-6., 2004. [18] M.H.A. Hassan, nanotechnology: small things and big changes in the developing world, Science (80) 309 (2005) 65 66. Available from: https://doi.org/10.1126/science.1111138. [19] R.P. Feynman, There’s plenty of room at the bottom, Eng. Sci. 23 (1960) 22 36. Available from: http://resolver.caltech.edu/CaltechES:23.5.1960Bottom. [20] F. Adams, C. Barbante, Chemical imaging analysis, Elseiver, Amsterdam, Netherlands, 2015. Available from: https://doi.org/10.1016/B978-0-444-63439-9.00004-9. [21] S. Bu¨yu¨ktiryaki, F. Yılmaz, R. Say, A. Erso¨z, Proteinous polymeric shell decorated nanocrystals for the recognition of immunoglobulin M, J. Fluoresc. (2019). Available from: https://doi.org/10.1007/s10895-019-02373-5. [22] S. Bu¨yu¨ktiryaki, L. Uzun, A. Denizli, R. Say, A. Erso¨z, Simultaneous depletion of albumin and immunoglobulin G by using twin affinity magnetic nanotraps, Sep. Sci. Technol. 51 (2016) 2080 2089. Available from: https://doi.org/10.1080/ 01496395.2016.1200086. [23] Y. Zhang, C. Wang, J. Yeom, Filtration-guided assembly for patterning onedimensional nanostructures, Nanotechnology 28 (2017) 145302. Available from: https://doi.org/10.1088/1361-6528/aa604d. [24] M.C. Roco, Nanoscale science and engineering: unifying and transforming tools, AIChE J. 50 (2004) 890 897. Available from: https://doi.org/10.1002/aic.10087. [25] K. Scida, P.W. Stege, G. Haby, G.A. Messina, C.D. Garcı´a, Recent applications of carbon-based nanomaterials in analytical chemistry: critical review, Anal. Chim. Acta. 691 (2011) 6 17. Available from: https://doi.org/10.1016/j.aca.2011.02.025. [26] S. Ge, F. Lan, F. Yu, J. Yu, Applications of graphene and related nanomaterials in analytical chemistry, New J. Chem. 39 (2015) 2380 2395. Available from: https://doi.org/ 10.1039/c4nj01783h. [27] C.M. Hussain, CHAPTER 19. Magnetic Nanomaterials for Environmental Analysis, in: B.K. Chaudhery Mustansar Hussain (Ed.), Advanced Environmental Analysis Applications of Nanomaterials, vol. 2, Royal Society of Chemistry, 2017, pp. 1 13. ,https://doi.org/10.1039/9781782629139-00001.. [28] L. He, C.S. Toh, Recent advances in analytical chemistry a material approach, Anal. Chim. Acta. 556 (2006) 1 15. Available from: https://doi.org/10.1016/j. aca.2005.08.042. [29] I. de la Calle, V. Romero-Rivas, Applications of nanomaterials advances and key technologies, micro and nano technologies, Elsevier, Duxford, Cambridge, UK, 2018. Available from: https://doi.org/10.1016/b978-0-08-101971-9.00010-7.

Modern age of analytical chemistry: nanomaterials

39

[30] J. Gonza´lez-Sa´lamo, B. Socas-Rodrı´guez, A.V. Herrera-Herrera, J. Herna´ndez-Borges, Nanomaterials in chromatography current trends in chromatographic research technology and techniques, Elsevier, Amsterdam, Netherlands, 2018. Available from: https:// doi.org/10.1016/b978-0-12-812792-6.00001-7. [31] N. Sehati, N. Dalali, S. Soltanpour, M.S. Seyed Dorraji, Application of hollow fiber membrane mediated with titanium dioxide nanowire/reduced graphene oxide nanocomposite in preconcentration of clotrimazole and tylosin, J. Chromatogr. A 1420 (2015) 46 53. Available from: https://doi.org/10.1016/j.chroma.2015.09.063. [32] Z. Ghoraba, B. Aibaghi, A. Soleymanpour, Application of cation-modified sulfur nanoparticles as an efficient sorbent for separation and preconcentration of carbamazepine in biological and pharmaceutical samples prior to its determination by highperformance liquid chromatography, J. Chromatogr. B 1063 (2017) 245 252. Available from: https://doi.org/10.1016/j.jchromb.2017.07.048. [33] Y. Pashaei, F. Ghorbani-Bidkorbeh, M. Shekarchi, Superparamagnetic graphene oxide-based dispersive-solid phase extraction for preconcentration and determination of tamsulosin hydrochloride in human plasma by high performance liquid chromatography-ultraviolet detection, J. Chromatogr. A 1499 (2017) 21 29. Available from: https://doi.org/10.1016/j.chroma.2017.03.038. [34] S.K. Kailasa, H.-F. Wu, Nanomaterial-based miniaturized extraction and preconcentration techniques coupled to matrix-assisted laser desorption/ionization mass spectrometry for assaying biomolecules, TrAC Trends Anal. Chem. 65 (2015) 54 72. Available from: https://doi.org/10.1016/j.trac.2014.09.011. [35] P.-R. Sudhir, H.-F. Wu, Z.-C. Zhou, Identification of peptides using gold nanoparticleassisted single-drop microextraction coupled with AP-MALDI mass spectrometry, Anal. Chem. 77 (2005) 7380 7385. Available from: https://doi.org/10.1021/ ac051162m. ˇ [36] I. Popovi´c, M. Neˇsi´c, M. Vranjeˇs, Z. Saponji´ c, M. Petkovi´c, TiO 2 nanocrystals assisted laser desorption and ionization time-of-flight mass spectrometric analysis of steroid hormones, amino acids and saccharides. Validation and comparison of methods, RSC Adv. 6 (2016) 1027 1036. Available from: https://doi.org/10.1039/C5RA20042C. [37] N. Pourreza, H. Sharifi, H. Golmohammadi, Curcumin nanoparticles combined with cloud point extraction for citrate determination in food and drug samples, Microchem. J. 129 (2016) 213 218. Available from: https://doi.org/10.1016/j.microc.2016.06.023. [38] A. Speltini, D. Merli, A. Profumo, Analytical application of carbon nanotubes, fullerenes and nanodiamonds in nanomaterials-based chromatographic stationary phases: a review, Anal. Chim. Acta. 783 (2013) 1 16. Available from: https://doi.org/10.1016/j. aca.2013.03.041. [39] M.L. Castillo-Garcı´a, M.P. Aguilar-Caballos, A. Go´mez-Hens, Nanomaterials as tools in chromatographic methods, TrAC Trends Anal. Chem. 82 (2016) 385 393. Available from: https://doi.org/10.1016/j.trac.2016.06.019. ´ . Gonza´lez-Curbelo, J. Herna´ndez-Borges, M.A ´ . Rodrı´guez[40] A.V. Herrera-Herrera, M.A Delgado, Carbon nanotubes applications in separation science: a review, Anal. Chim. Acta. 734 (2012) 1 30. Available from: https://doi.org/10.1016/j.aca.2012.04.035. [41] B. Franze, I. Strenge, C. Engelhard, Separation and detection of gold nanoparticles with capillary electrophoresis and ICP-MS in single particle mode (CE-SP-ICP-MS), J. Anal. At. Spectrom. 32 (2017) 1481 1489. Available from: https://doi.org/10.1039/ c7ja00040e. [42] A. Chetwynd, E. Guggenheim, S. Briffa, J. Thorn, I. Lynch, E. Valsami-Jones, Current application of capillary electrophoresis in nanomaterial characterisation and its

40

[43]

[44]

[45]

[46]

[47] [48]

[49]

[50]

Handbook of Nanomaterials in Analytical Chemistry

potential to characterise the protein and small molecule corona, Nanomaterials 8 (2018) 99. Available from: https://doi.org/10.3390/nano8020099. Y. Zhang, W. Wang, X. Ma, L. Jia, Polydopamine assisted fabrication of titanium oxide nanoparticles modified column for proteins separation by capillary electrochromatography, Anal. Biochem. 512 (2016) 103 109. Available from: https://doi.org/10.1016/j. ab.2016.08.015. C. Manzano, E. Hoh, S.L.M. Simonich, Improved separation of complex polycyclic aromatic hydrocarbon mixtures using novel column combinations in GC 3 GC/ToFMS, Environ. Sci. Technol. 46 (2012) 7677 7684. Available from: https://doi.org/ 10.1021/es301790h. C. Manzano, E. Hoh, S.L.M. Simonich, Quantification of complex polycyclic aromatic hydrocarbon mixtures in standard reference materials using comprehensive twodimensional gas chromatography with time-of-flight mass spectrometry, J. Chromatogr. A 1307 (2013) 172 179. Available from: https://doi.org/10.1016/j. chroma.2013.07.093. N.J. Wittenberg, C.L. Haynes, Using nanoparticles to push the limits of detection, Wiley Interdiscip. Rev. Nanomed. Nanobiotechnol. 1 (2009) 237 254. Available from: https://doi.org/10.1002/wnan.19. ´ .I. Lo´pez-Lorente, Encyclopedia of analytical chemistry, John Wiley & M. Valca´rcel, A Sons, 2016, pp. 1 26. Available from: https://doi.org/10.1002/9780470027318.a9533. ´ . Rı´os, Analytical nanoscience and M. Laura Soriano, M. Zougagh, M. Valca´rcel, A nanotechnology: where we are and where we are heading, Talanta 177 (2018) 104 121. Available from: https://doi.org/10.1016/j.talanta.2017.09.012. ´ .I. Lo´pez-Lorente, M. Valca´rcel, Analytical nanoscience and nanotechnology, A Elsevier, Amsterdam, Netherlands, 2014. Available from: https://doi.org/10.1016/B9780-444-63285-2.00001-8. S. Bu¨yu¨ktiryaki, Y. Su¨mbelli, R. Kec¸ili, C.M. Hussain, Lab-on-chip platforms for environmental analysis, third edition, Encylopedia of Analytical Science, Ref. Modul. Chem. Mol. Sci. Chem. Eng. 3 8, Elsevier, 2018, pp. 267 273. Available from: https://doi.org/10.1016/b978-0-12-409547-2.14489-0.

Nanomaterials for microextraction techniques in bioanalysis

3

Mohammad Mahdi Moein1, Abbi Abdel-Rehim2 and Mohamed Abdel-Rehim1,3 1 Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institute and Stockholm County Council, Stockholm, Sweden, 2Faculty of Science and Engineering, University of Manchester, Manchester, United Kingdom, 3Functional Materials Division, Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, Isafjordsgatan 22, Kista, SE-164 40 Stockholm, Sweden

3.1

Introduction

In recent years, application of nanomaterials in research areas such as chromatography and sample preparation has attracted the attention of many research groups [1 4]. It is well known that the nanomaterials have remarkable properties compared to bulk materials. Some of these properties are their physical and chemical stability and their high surface-area-to-volume ratio. These properties have made the nanomaterials an excellent candidate for surface adsorption applications such as solid-phase extraction techniques [5]. Several scientists have showed that nanomaterials have higher efficiency for adsorption of various compounds in gaseous or liquid phases. Today, nanotechnology is commonly used in many fields such as medicine, biotechnology, electronics, and agriculture. Sample preparation is important in chemical analysis, particularly in bioanalysis because of the complexity of biological matrices [5]. Sample preparation is the first and the most important step in the bioanalytical procedures. Sample preparation is critical issue for the analysis of drugs and metabolites in biological fluids. Therefore a robust, sensitive, and high-throughput sample preparation with short turnaround time is essential. Current developments in the sample preparation area focus on the miniaturization of the methodology. In addition, current developments in the sample preparation for bioanalysis focus on the miniaturization of the process to increase the sample throughput and to decrease the sample volume and solvents required [5 8]. This chapter will present a comprehensive study on recently published papers in the application of nanomaterials as sorbent for different microextraction techniques. Various frequently used nanomaterials will be classified, and application of these materials will be reviewed. In the present section, different types of nanomaterials for some commercially available microextraction techniques will be briefly discussed. Handbook of Nanomaterials in Analytical Chemistry. DOI: https://doi.org/10.1016/B978-0-12-816699-4.00003-7 Copyright © 2020 Elsevier Inc. All rights reserved.

44

3.2

Handbook of Nanomaterials in Analytical Chemistry

Nanomaterials classifications

There are several ways to classify the nanomaterials, and composition aspect is a popular way as it is shown in Fig. 3.1B and will briefly be presented.

3.2.1 Metallic/metallic oxide nanoparticles Noble metallic nanoparticles (NPs) and mixed metallic NPs, such as Fe3O4, Al2O3, TiO2, ZrO2, CeO2, and MnO, due to their high surface capacity, high adsorption capacity, and chemical, physical, and thermal stability, are nominated in samplepreparation techniques [3].

3.2.2 Silicon oxide nanoparticles Silicon oxide (SiO2) NPs are the most widespread sort of NPs because of their simplicity in preparation, low cost, and biocompatibility. In addition, they can be prepared or used to modify the surface in different styles such as nanofiber core-shell layers, nanotubes and nanowires, nanoporous, packed, and monolithic [9 11].

Figure 3.1 (A) Some commercially available microextraction devices for sorptive extraction [3]. (B) Nanomaterial composition categories.

Nanomaterials for microextraction techniques in bioanalysis

45

3.2.3 Magnetic nanoparticles Magnetic NPs are further sorted as NPs that can separate analytes from complex matrix and can easily be separated using an external magnet. These simple, straightforward, and biocompatible particles can be used as solid-phase extraction (SPE) sorbents, specially iron oxide NPs in both magnetite and maghemite formats [12 14].

3.2.4 Polymer nanoparticles 3.2.4.1 Organic nanomaterials Organic nanomaterials have gained much attention because of their high adsorption capacity, biocompatibility, and high chemical and thermal stability. Organic nanomaterials can be used individually, supporting materials and core shell for inorganic nanomaterials. Recently, conductive organic materials have been developed as new sorbents with high capacity [15,16].

3.2.4.2 Inorganic and mixed polymers Xerogels (specially silica based), aerogels, metalorganic frameworks, and core-shell layers are the most popular inorganic nanomaterials with proper porosity. From this nanomaterials category, polydimethylsiloxane (PDMS) or silicone rubber is commercially available and is extremely practical for the extraction aims [17,18].

3.2.4.3 Selective nanomaterials Selective extraction is valuable ability for a sorbent that can be used in sample preparation techniques. Molecularly imprinted polymers (MIPs), nanopolymers, are the most famous selective sorbents for extraction, which are established in harsh biological samples and can be prepared with different methods, such as free-radical based and sol gel method [19]. MIP nanomaterials can be used in different formats in different sample preparation methods.

3.2.5 Carbon-based nanomaterials Carbon nanotubes (CNTs), grapheme (G), graphene oxide (GO), and fullerenes are the most well-known carbon-based nanomaterials. CNTs can be categorized further as single-walled (SWCNTs) or multi-walled CNTs (MWCNTs) format and have attained huge attention because of their high capacity and high interaction ability. In addition, similar to CNTs, G, GO, and reduced GO (RGO) are well-known sorbents used for extraction because of their high physical stability and proper ability to be functionalized.

46

3.3

Handbook of Nanomaterials in Analytical Chemistry

Nanomaterials application in microextraction methods

Sorptive extraction methods such as SPE, solid-phase microextraction (SPME), microextraction by packed syringe (MEPS), stir bar sorptive extraction (SBSE), and dispersive SPE have made huge assistance to eliminate the interference compounds, preconcentration, and conversion of interested analytes to a proper shape before injecting into analytical instruments. Sorbents of these methods play an important function to remove the interferences and to raise the selectivity. Therefore nanomaterials with high chemical and physical stability and high adsorption capacity were used successfully to get these aims. The recent applications of nanomaterials in microextraction techniques are gathered in Table 3.1 and they will be briefly presented in the following sections.

3.4

Recent nanomaterials applications in microextraction techniques

3.4.1 In-tube solid-phase microextraction In-tube SPME (IT-SPME) coupled with HPLC method, since its emergence in 1997 by Dr. Pawliszyn [36], has attracted interest because of its advantages such as reduction of the analysis time and use of low-volume solution. IT-SPME tool can be prepared in two ways: (1) draw/eject mode that draw/eject cycles through the capillary can be considered to extract analyte from the sample, and (2) in-valve mode that analyte loads through an injector loop and then transferred to the analytical column using the mobile phase with shifting the valve position (Fig. 3.2) [37]. Recently nanomaterials have been applied in IT-SPME in combination with liquid chromatography (IT-SPME-NanoLC) and improved some challenges in this field that we will discuss here. In one study, new polar-coated capillary based on tetramethylorthosilicate (TEOS) and trimethoxymethylsilane (MTEOS) containing SiO2 NPs was synthesized and used for high efficient extraction of intact and degraded polar triazines in water and recovered struvite and determination with LC [20]. To make in-tube solid phase, a commercial empty capillary column of fused silica was used and TEOS-MTEOS-SiO2 NPs packed on it and coupled online to LC. IT-SPME-NanoLC method showed 10 25 times higher sensitivity compared to other similar methods such as IT-SPME capillary LC. In an interesting study, basalt fibers’ surface was modified by nano-CaCO3 and was used as a sorbent for online extraction of estrogens in water sample with HPLC [21]. Nano-CaCO3 packed in polyetheretherketone in this work showed superior extraction efficiency, stability and sensitivity. Packed IT-SPME technique has high application but it is not highly efficient for ion compounds. To overcome this defect, a novel sorbent based on Co/Cr(NO32)-layered double hydroxides, nanosheets was synthesized and packed in HPLC guard column (Fig. 3.3) and applied for extraction of acidic

Table 3.1 Recent applications of nanomatereials as sorbent for microextraction techniques Analyte

Nanomaterials

Microextraction method

Matrix

Analytical instrument

Ref.

TriazinesTriazines

TEOS-MTEOS with SiO2 NPs

In-tube SPME

Nano-calcium carbonate Cobalt/chromium-layered double hydroxide (Co/Cr (NO32)-LDH) nanosheets Nickel sulfide nanomaterial Nano-polypyrrole-coated Fe3O4

In-tube SPME In-tube SPME

NanoLC and capillary LC HPLC-DAD HPLC-UV

[20]

Estrogens Acidic pesticides

Water and struvite samples Water samples Water samples

DSPME DSPME

HPLC-UV HPLC-UV

[23] [24]

Methamphetamine Cyhalothrin and fenvalerate Parabens

Fe3O4@PPy magnetic NPs Nano-structured gemini-based supramolecular Nano-structured gemini-based supramolecular

DSPME SUPRAS-SPME SUPRAS-SPME

HPLC-UV HPLC-UV HPLC-UV

[25] [26] [27]

Zirconium and Hafnium Phthalate esters Lido, Prilo, Ropi

Nano-structured supramolecular Nano-hydroxyapatite sorbent Reduced graphene oxide

SUPRAS-SPME MEPS MEPS

ICP-AES GC-FID LC-MSMS

[28] [29] [30]

Losartan and valsartan

Ni:Zn-sulfide NPs sol gel

SBSE

LC-UV

[31]

Volatile organic compounds Octylphenol and nonylphenol Hexaconazole, penconazole, and diniconazole Pesticide carbaryl

Nanofibrillated mesoporous carbon

SPME

Pharmaceutical samples Waste water and pharmaceutical samples Human urine Water and soil samples Cosmetics, beverages, and water samples Ore sample Water samples Human plasma and saliva Human urine and plasma Aqueous solutions

GC-MS

[32]

Carboxylated carbon nano-spheres

Environmental water samples Vegetable samples

GC-MS

[33]

Polyethylene glycol grafted flower-like cupric nano oxide

Nano-fiberSPME Nano-hollow fiber SPME

HPLC-UV

[34]

Nano-MIP

Nano-MIP-SPME

Water samples

UV

[35]

Thymol and carvacrol Megestrol acetate and levonorgestrel

[21] [22]

48

Handbook of Nanomaterials in Analytical Chemistry

Figure 3.2 In-tube solid-phase microextraction in (A) draw/eject mode and (B) in-valve mode. Source: Reused with permission from Y. M-Martinez, R. H-Herna´ndez, J. V-Andre´s, C. MLegua, P. C-Falco´, Recent advances of in-tube solid-phase microextraction, Trends Anal. Chem. 71 (2015) 205 213.

pesticides from water samples [22]. IT-SPME technique is an online promising method with high efficiency and repeatability can be used as a potential candidate for further applications in extraction fields in the near future.

3.4.2 Dispersive solid-phase microextraction Dispersive solid-phase extraction is a sort of SEP in which solid phase disperses in the solution that contains interested analyte and several research groups have used it [38 42]. However, dispersive solid-phase microextraction (DSPME) rarely received attention and few works reported this method and here we will describe them. In a study, thymol and carvacrol in pharmaceutical samples were extracted by ultrasound-assisted microextraction-nanomaterial solid-phase dispersion (UAMENMSPD) and analyzed with HPLC. In this work, as shown in Fig. 3.4, nickel sulfide nanomaterial loaded on activated carbon (NiS-NP-AC) was used for DSPME and results show proper stability and high sensitivity [23].

Nanomaterials for microextraction techniques in bioanalysis

49

Figure 3.3 In-tube solid-phase microextraction preparation. Source: Reused with permission from H. Asiabi, Y. Yamini, M. Shamsayei, Using cobalt/ chromium layered double hydroxide nano-sheets as a novel packed in-tube solid phase microextraction sorbent for facile extraction of acidic pesticides from water samples, New J. Chem. 2018,42, 9935.

Ultrasonic

Attach a filter

Desorption of analytes by 600 µL of acetonitrile

10 min Adsorbent+analytes

Aqueous sample

Addition of 11 mg of NiS:AC nanoparticles

Closed the syringe

Adsorption process

Emit the liquid-phase contents from adsorbent

Analysis

Figure 3.4 Ultrasound-assisted microextraction-nanomaterial solid-phase dispersion process. Source: Reused with permission from M. Roosta, M. Ghaedi, A. Daneshfar, R. Sahraei, Ultrasound assisted microextraction-nano material solid phase dispersion for extraction and determination of thymol and carvacrolin pharmaceutical samples: experimental design methodology, J. Chromatogr. B 975 (2015) 34 39.

In another approach, magnetic SPE (MSPE) in combination with dispersive liquid liquid microextraction (DLLME) was applied successfully for megestrol acetate levonorgestrel in biological and waste water samples [24]. In optimization of the mentioned method, a new bio-DLLME (Bio-DLLME) technique coupled

50

Handbook of Nanomaterials in Analytical Chemistry

with MSPE was presented for extraction of methamphetamine in human urine samples using Fe3O4@PPy magnetic NPs. Bio-DLLME works based on biosorption phenomenon using binary solvent system including an extraction-phase solvent and a disperser solvent (polar and water miscible solution) [25]. All these studies approved that using nanomaterials in DSPME as a straightforward and green method presenting high preconcentration factor can be a good candidate for extraction of analytes from biological fluids in the near future.

3.4.3 Supramolecular solvent microextraction Supramolecular solvents (SUPRASs) technique developed by Perez Bendito in 2007 [43] was based on analyte dividing among an alkyl carboxylic acid-based self-assembled nano-structured solvent and an aqueous sample solution. Phase separation happens by optimizing the pH, salt addition, or changing temperature [44 48]. These surfactants represent a series of superior properties in comparison with conventional single-chain surfactants. The dicationic quaternary ammonium compounds referred to as CMCSCM (Me), where M and S stand for the number of carbon atoms in the side alkyl chain and the methylene spacer, have been by far the most investigated dimeric surfactant [26]. Nevertheless, pH limitation is a drawback for this method, and then in one interesting study, a novel synthetic nano-structured gemini-based supramolecular solvent for the microextraction of cyhalothrin and fenvalerate from water and soil samples was suggested to overcome this drawback [26]. Taking further this method, other groups made a supramolecular solvent, consisting of aggregates of 14-2-14 gemini surfactant in propanol:water mixtures, which was synthesized and used for the microextraction of parabens in cosmetics, beverages, and water samples and was analyzed with HPLC with quite good sensitivity and repeatability [27]. In addition, zirconium (Zr) from hafnium (Hf) were extracted nano-SUPRAS, which is made up of reverse micelles of decanoic acid from ore samples and measured with IVP-AES [28]. This method is quite cheap, just needs 30 µL of supramolecular solvent and shows proper selectivity.

3.4.4 Microextraction by packed syringe MEPS was introduced first time in 2004 by Dr. Abdel-Rehim [49]. In MEPS as a miniaturized SPE method, 1 4 mg of sorbent packed in a syringe between two frits and needs low organic solutions and can be connected online with GC and LC equipment (Fig. 3.1A). MEPS was applied for the extraction of different analytes in biological samples [50 53]. Recently, nanomaterials were used as sorbent for this technique to provide better selectivity and sensitivity. Nanomaterials made of hydroxyapatite were prepared with sol gel technique and used as MEPS sorbet for the extraction of phthalate esters from water sample and then separated with gas chromatography [29]. Sol gel method is a simple technique and nanomaterials can be created at low temperature with high thermal, chemical, and physical stability. Nanomaterials with small and uniform shapes can improve MEPS performance and prevent from blocking even when facing complex matrices, which is a challenge in

Nanomaterials for microextraction techniques in bioanalysis

51

MEPS development. A simple alkoxide-based sol gel method, utilizing Ca (NO3)2.4H2O and tri-ethyl phosphate (PO(OC2H5)3;TEP) precursors, is used to synthesize nano-hydroxyapatite as novel MEPS sorbent. The sorbent showed good repeatability and proper recovery for extraction of phthalate esters from water samples. To the best of our knowledge, so far there is no more reported application of nanomaterials in MEPS that can be an interesting field in near future to increase the MEPS performance by reducing the blockage risk, extend the life-time, and decrease the carryover. Recently, RGO was used as a sorbent in MEPS for the extraction of local anesthetics (lidocaine, prilocaine, and ropivacaine) from human plasma and saliva samples [30].

3.4.5 Stir bar sorptive extraction SBSE technique was introduced in 1999 by Baltussen et al. [54]. In SBSE technique, a PDMS-coated stir bar was used as a sorptive element (Fig. 3.1A). The coated SBSE be able to be immersed in the sample solution then, the stir bar can be transferred for desorption using solvent or heating. Nanosorbent was used to enhance conventional SBSE efficiency for losartan and valsartan in human urine and plasma [31] (Table 3.1). In this example, the stir bar was coated with nickel: zinc sulfide (Ni:ZnS) NPs loaded onto activated carbon as well as 1-ethyl-3methylimidazolium hexafluorophosphate ionic liquid using the sol gel technique. Their results illustrated that the synthesized nanocoating provides much higher extraction efficiency than activated carbon coating alone.

3.4.6 Nanofibers as sorbent in microextraction techniques Nanofibers were used as sorbent in microextraction techniques. In an interesting approach nanofibrillated mesoporous carbon (FMC) SPME fiber was prepared by carbonization of the ionic liquid in the presence of SBA-15 as a structuretransducing agent [32]. Briefly, ionic liquid-derived nano-FMC was synthesized and part of it was limed on a stainless steel wire. The coated wire was heated to eliminate non-bonded particles and it was inserted into the GC injection port to be cleaned in a helium environment. This nanofiber was applied for extraction of a number of volatile organic compounds in aqueous samples and analyzed with GC-MS. In another study, a coated fiber with carboxylated carbon nano-spheres (CNSs-COOH) via physical adhesion was used for octylphenol and nonylphenol in environmental water samples in combination with GC-MS [33]. It is worth mentioning that SPME suffers from some drawbacks such as fiber fragility and short life-time in harsh pH, and salt-related problems and to overcome these problems, hollow fiber (HF) was suggested by Es’haghi in SPME [34]. In a study, HF-SPME sorbents were fabricated with the sol gel technique. For this aim, HF surface was modified with poly-PEG-g-CuO-NPs that was prepared by hydrothermal method and it was applied for SPME of hexaconazole, penconazole, and diniconazole in vegetable samples. The schematic process is shown in Fig. 3.5.

52

Handbook of Nanomaterials in Analytical Chemistry

Figure 3.5 Hollow-fiber solid-phase microextraction process. Source: Reused with permission from N. Feizi, Y. Yamini, M. Moradi, B. Ebrahimpour, Nano-structured gemini-based supramolecular solvent for the microextraction of cyhalothrin and fenvalerate, J. Sep. Sci. 2016, 39, 3400 3409.

3.4.7 Molecularly imprinted polymer nanomaterials in microextraction techniques Different research groups have used different strategies to improve SMPE extraction efficiency for bioanalysis by using MIPs nanomaterial coating on silica fiber or capillary [55,56]. Recently, nano-MIP particles were prepared and used for selective SPME of pesticide carbaryl from water samples [35].

3.5

Concluding remarks

It can be concluded that many bioanalytical scientists are interested in the advantages of nanotechnology to improve the efficiency of conventional extraction methods, as well as establish new innovative methods. The main basic feature of nanomaterials for microextraction is their high surface area providing higher sorption capacity than the conventional microscale sorbents. In this chapter, the progress in application and future aspect of MEPS and DPX as green, fast, high-throughput, and sensitive sample preparation techniques were briefly reviewed. The most important challenges these methods face today are to be more cost-effective, fully automated, and the stability in the complex matrices to be more applicable.

References [1] C.M. Hussain, Nanomaterials in Chromatography: Current Trends in Chromatographic Research Technology and Techniques, Elsevier, 2018. [2] S. Kanchi, S. Ahmed, M.I. Sabela, C.M. Hussain, Nanomaterials: Biomedical, Environmental, and Engineering Applications, John Wiley & Sons, 2017.

Nanomaterials for microextraction techniques in bioanalysis

53

[3] M. Ahmadi, H. Elmongy, T. Madrakian, M. Abdel-Rehim, Nanomaterials as sorbents for sample preparation in bioanalysis: a review, Anal. Chim. Acta 958 (2017) 1 21. [4] M.L. Castillo-Garcı´a, M.P. Aguilar-Caballos, A. Go´mez-Hens, Nanomaterials as tools in chromatographic methods, TrAC Trends Anal. Chem. 82 (2016) 385e393. [5] N. Ashri, M. Abdel-Rehim, Bioanalysis 3 (17) (2011) 1993 2008. [6] D. Banerjee, A.J. Cairns, J. Liu, R.K. Motkuri, S.K. Nune, C.A. Fernandez, et al., Potential of metaleorganic frameworks for separation of xenon and krypton, Accounts Chem. Res. 48 (2015) 211e219. [7] L. Chen, S. Xu, J. Li, Recent advances in molecular imprinting technology: current status, challenges and highlighted applications, Chem. Soc. Rev. 40 (2011) 2922e2942. [8] M. Abdel-Rehim, Z. Hassan, L. Blomberg, M. Hassan, On-line derivatization utilizing solid-phase microextraction (SPME) for determination of busulphan in plasma using gas chromatography-mass spectrometry (GC-MS), Therapeutic Drug Monitoring 25 (2003) 400 406. [9] F. Peng, Y. Su, Y. Zhong, C. Fan, S.T. Lee, Y. He, Silicon nanomaterials platform for bioimaging, biosensing, and cancer therapy, Accounts Chem. Res. 47 (2014) 612 623. [10] L. Xu, X. Qi, X. Li, Y. Bai, H. Liu, Recent advances in applications of nanomaterials for sample preparation, Talanta 146 (2016) 714 726. [11] A. Namera, A. Nakamoto, T. Saito, S. Miyazaki, Monolith as a new sample preparation material: recent devices and applications, J. Sep. Sci. 34 (2011) 901 924. [12] L.H. Reddy, J.L. Arias, J. Nicolas, P. Couvreur, Magnetic nanoparticles: design and characterization, toxicity and biocompatibility, pharmaceutical and biomedical applications, Chem. Rev. 112 (2012) 5818 5878. [13] R. Kaur, A. Hasan, N. Iqbal, S. Alam, M.K. Saini, S.K. Raza, Synthesis and surface engineering of magnetic nanoparticles for environmental cleanup and pesticide residue analysis: a review, J. Sep. Sci. 37 (2014) 1805 1825. [14] J.S. Beveridge, J.R. Stephens, M.E. Williams, The use of magnetic nanoparticles in analytical chemistry, Annu. Rev. Anal. Chem 4 (2011) 251 273. [15] H. Bagheri, M. Saraji, Conductive polymers as new media for solid-phase extraction: isolation of chlorophenols from water sample, J. Chromatogr. A 986 (2003) 111 119. [16] H. Bagheri, Z. Ayazi, M. Naderi, Conductive polymer-based microextraction methods: a review, Anal. Chim. Acta 767 (2013) 1 13. [17] J.-R. Li, J. Sculley, H.-C. Zhou, Metaleorganic frameworks for separations, Chem. Rev. 112 (2012) 869 932. [18] D. Banerjee, A.J. Cairns, J. Liu, R.K. Motkuri, S.K. Nune, C.A. Fernandez, et al., Potential of metaleorganic frameworks for separation of xenon and krypton, Accounts Chem. Res. 48 (2015) 211 219. [19] P. Dramou, P. Zuo, H. He, L.A. Pham-Huy, W. Zou, D. Xiao, et al., Development of novel amphiphilic magnetic molecularly imprinted polymers compatible with biological fluids for solid phase extraction and physicochemical behavior study, J. Chromatogr. A 1317 (2013) 110 120. [20] P. Serra-Mora, N. Jornet-Martinez, Y. Moliner-Martinez, P. Campı´ns-Falco´, In tubesolid phase microextraction-nano liquid chromatography: application to the determination of intact and degraded polar triazines in waters and recovered struvite, J. Chromatogr. A 1513 (2017) 51 58. [21] X. Wang, J. Feng, J. Feng, Y. Tian, C. Luo, M. Sun, Basalt fibers coated with nanocalcium carbonate for in-tube solid-phase microextraction and online analysis of estrogens coupled with high performance liquid chromatography, Anal. Methods 10 (2018) 2234.

54

Handbook of Nanomaterials in Analytical Chemistry

[22] H. Asiabi, Y. Yamini, M. Shamsayei, Using cobalt/chromium layered double hydroxide nano-sheets as a novel packed in-tube solid phase microextraction sorbent for facile extraction of acidic pesticides from water samples, New J. Chem. 42 (2018) 9935. [23] M. Roosta, M. Ghaedi, A. Daneshfar, R. Sahraei, Ultrasound assisted microextractionnano material solid phase dispersion for extraction and determination of thymol and carvacrolin pharmaceutical samples: experimental design methodology, J. Chromatogr. B 975 (2015) 34 39. [24] B. Ebrahimpour, Y. Yamini, S. Seidi, M. Tajik, Nano polypyrrole-coated magnetic solid phase extraction followed by dispersive liquid phase microextraction for trace determination of megestrol acetate and levonorgestrel, Anal. Chim. Acta 885 (2015) 98 105. [25] S.A. Haeria, S. Abbasi, S. Sajjadifar, Bio-dispersive liquid liquid microextraction based on nano rhaminolipid aggregates combined with magnetic solid phase extraction using Fe3O4@PPy magnetic nanoparticles for the determination of methamphetamine in human urine, J. Chromatogr. B 1063 (2017) 101 106. [26] N. Feizi, Y. Yamini, M. Moradi, B. Ebrahimpour, Nano-structured gemini-based supramolecular solvent for the microextraction of cyhalothrin and fenvalerate, J. Sep. Sci. 39 (2016) 3400 3409. [27] N. Feizi, Y. Yamini, M. Moradi, M. Karimi, Q. Salamat, H. Amanzadeh, A new generation of nano-structured supramolecular solvents based on propanol/gemini surfactant for liquid phase microextraction, Anal. Chim. Acta 953 (2017) 1 9. [28] Q. Salamat, Y. Yamini, M. Moradi, M. Safari, N. Feizi, Extraction and separation of zirconium from hafnium by using nano-structured supramolecular solvent microextraction method, J. Iran. Chem. Soc. 15 (2018) 293 301. [29] A. Amiri, M. Chahkandi, A. Targhoo, Synthesis of nano-hydroxyapatite sorbent for microextraction in packed syringe of phthalate esters in water samples, Anal. Chim. Acta 950 (2017) 64 70. [30] M. Ahmadi, M.M. Moein, T. Madrakian, A. Afkhami, S. Bahar, M. Abdel-Rehim, Reduced graphene oxide as an efficient sorbent in microextraction by packed sorbent: determination of local anesthetics in human plasma and saliva samples utilizing liquid chromatography-tandem mass spectrometry, J. Chromatogr. B 1095 (2018) 177 182. [31] A.A. Pebdani, S. Dadfarnia, A.M.H. Shabani, S. Khodadoust, S. Haghgoo, Application of modified stir bar with nickel:zinc sulphide nanoparticles loaded on activated carbon as a sorbent for preconcentration of losartan and valsartan and their determination by high performance liquid chromatography, J. Chromatogr. A 1437 (2016) 15 24. [32] M.M. Abolghasemi, B. Karimi, V. Yousefi, H. Behzadni, H. Barzegar, M. Piryaei, Ionic liquid-derived nano-fibrillated mesoporous carbon based on solid-phase microextraction fiber for the analysis of volatile organic compounds from aqueous solutions, New J. Chem. 39 (2015) 6085 6091. [33] S.X. Gong, X. Wang, L. Li, M.L. Wang, R.S. Zhao, Enrichment and determination of octylphenol and nonylphenol in environmental water samples by solid-phase microextraction with carboxylated carbon nano-spheres coating prior to gas chromatography mass spectrometry, Anal. Bioanal. Chem. 407 (2015) 8673 8679. [34] A.Z. Shiraz, A. Sarafraz-Yazdi, Z. Es’haghi, Polyethylene glycol grafted flower-like cupric nano oxide for the hollow-fiber solid-phase microextraction of hexaconazole, penconazole, and diniconazole in vegetable samples, J. Sep. Sci. 39 (2016) 3137 3144. [35] A.A. Bazrafshan, M. Ghaedi, Z. Rafiee, S. Hajati, A. Ostovan, Nano-sized molecularly imprinted polymer for selective ultrasound-assisted microextraction of pesticide

Nanomaterials for microextraction techniques in bioanalysis

[36] [37] [38]

[39] [40]

[41]

[42]

[43]

[44]

[45]

[46]

[47]

[48]

[49] [50] [51] [52] [53] [54]

55

carbaryl from water samples: spectrophotometric determination, J. Coll. Inter. Sci. 498 (2017) 313 322. R. Eisert, J. Pawliszyn, Anal. Chem. 69 (1997) 3140. Y. M-Martinez, R. H-Herna´ndez, J. V-Andre´s, C. M-Legua, P. C-Falco´, Recent advances of in-tube solid-phase microextraction, Trends Anal. Chem. 71 (2015) 205 213. M. Rezaee, Y. Assadi, M.R. Milani Hosseini, E. Aghaee, F. Ahmadi, S. Berijani, Determination of organic compounds in water using dispersive liquid liquid microextraction, J. Chromatogr. A 1116 (2006) 1 9. M. Rezaee, Y. Yamini, M. Faraji, Evolution of dispersive liquid liquid microextraction method, J. Chromatogr. A 1217 (2010) 2342 2357. M. Rezaee, Y. Yamini, S. Shariati, A. Esrafili, M. Shamsipur, Dispersive liquid liquid microextraction combined with high-performance liquid chromatography UV detection as a very simple, rapid and sensitive method for the determination of bisphenol a in water samples, J. Chromatogr. A 1216 (2009) 1511 1514. P. Liang, H. Sang, Determination of trace lead in biological and water samples with dispersive liquid liquid microextraction preconcentration, Anal. Biochem. 380 (2008) 21 25. R.E. Rivas, I. Lo´pez-Garcı´a, M. Herna´ndez-Co´rdoba, Speciation of very low amounts of arsenic and antimony in waters using dispersive liquid liquid microextraction and electrothermal atomic absorption spectrometry, Spectrochim. Acta B 64 (2009) 329 333. F.-J. Ruiz, S. Rubio, D. Perez-Bendito, Water-induced coacervation of alkylcarboxylic acid reverse micelles: phenomenon description and potential for the extraction of organic compounds, Anal. Chem. 79 (2007) 7473 7484. E. Yilmaz, M. Soylak, Development a novel supramolecular solvent microextraction procedure for copper in environmental samples and its determination by microsampling flame atomic absorption spectrometry, Talanta 126 (2014) 191 195. F. Aydin, E. Yilmaz, M. Soylak, Supramolecular solventbased dispersive liquid-liquid microextraction of copper from water and hair samples, RSC Adv. 5 (2015) 40422 40428. E. Yilmaz, M. Soylak, Supramolecular solvent microextraction of gold prior to its determination by microsample injection system coupled with flame atomic absorption spectrometry, RSC Adv. 4 (2014) 47396 47401. M. Ferdowsi, A. Taghian, A. Najafi, M. Moradi, Application of a nanostructured supramolecular solvent for the microextraction of diphenylamine and its mono-nitrated derivatives from unburned single-base propellants, J. Sep. Sci. 38 (2015) 276 282. M. Tayyebi, Y. Yamini, M. Moradi, Reverse micellemediated dispersive liquid liquid microextraction of 2,4-dichlorophenoxyacetic acid and 4-chloro-2-methylphenoxyacetic acid, J. Sep. Sci. 35 (2012) 2491 2498. M. Abdel-Rehim, J Chromatogr B 801 (2) (2004) 317 321. R. Said, M. Kamel, A. Elbeqqali, M. Abdel-Rehim, Bioanalysis 2 (2) (2010) 197 205. S.M. Daryanavard, A. Jeppsson-Dadoun, L.I. Andersson, M. Hashemi, A. Colmsjo, M. Abdel-Rehim, Biomed. Chromatogr. 27 (2013) 1481 1488. A. El-Beqqali, M. Abdel-Rehim, J Sep. Sci. 30 (3) (2007) 421 424. M. Vita, M. Abdel-Rehim, C. Nilsson, Z. Hassan, P. Skansen, H. Wan, et al., J. Chromatogr. B 821 (2005) 75 80. E. Baltussen, P. Sandra, F. David, C. Cramers, Stir bar sorptive extraction (SBSE), a novel extraction technique for aqueous samples: theory and principles, J. Microcolumn Sep. 11 (1999) 737 747.

56

Handbook of Nanomaterials in Analytical Chemistry

[55] B.B. Prasad, A. Srivastava, M.P. Tiwari, Highly sensitive and selective hyphenated technique (molecularly imprinted polymer solid-phase microextraction- molecularly imprinted polymer sensor) for ultra trace analysis of aspartic acid enantiomers, J. Chromatogr. A 1283 (2013) 9 19. [56] N. Ye, J. Li, Determination of dopamine, epinephrine, and norepinephrine by opentubular capillary electrochromatography using graphene oxide molecularly imprinted polymers as the stationary phase, J. Sep. Sci. 37 (2014) 2239 2247.

Recent advances in solid-phase extraction techniques with nanomaterials

4

Yingying Wen Environmental Science, Hainan Medical University, Haikou, P.R. China

4.1

Introduction

In the past years, analytical chemistry has been a significant field in chemistry, medicine, industry, agricultural, and so on. This is because of the fact that analytical chemistry took over qualitative supervision over all aspects of our lives, from the analysis conducted to satisfy the needs of various industries (food, pharmaceutical, cosmetic, fuel, and energy) through the clinical analysis, the analyses made in the field of cognitive research, and ending with the environmental analysis [1]. Sample preparation as a crucial part has been considered to be the bottleneck of the whole analytical process. Sample preparation starts from enhancement of selectivity and sensitivity of the analysis to improving analytical criteria and/or protecting the analytical instrument from possible damage. It is of utmost importance for obtaining the analytes of interest in a suitable injection solution able to provide reliable and accurate results. The beneficial points of sample preparation include the following: 1. reducing or eliminating matrix interferences such as endogenous or exogenous macromolecules, small molecules, and salts; 2. increasing the sensitivity or selectivity for analytes; 3. guaranteeing a reproducible method for analysis; and 4. providing the optimistic forms for the analytes’ instrumental analysis.

Therefore, numerous researches focusing on sample preparation methods have been reported [2 7]. These reviews have described the sample preparation methods in detail, including traditional methods such as solid-phase extraction (SPE), liquid liquid extraction (LLE), protein precipitation (PP), novel sample preparation techniques such as solid-phase microextraction (SPME), matrix solid-phase dispersion (MSPD), stir-bar sorptive extraction (SBSE), microextraction by packed sorbent (MEPS), disposable pipette tips extraction, single-drop microextraction, hollow-fiber liquid-phase microextraction, dispersive liquid liquid microextraction. In all the above techniques, sorbent-based methods such as SPE, SPME, MSPD,

Handbook of Nanomaterials in Analytical Chemistry. DOI: https://doi.org/10.1016/B978-0-12-816699-4.00004-9 Copyright © 2020 Elsevier Inc. All rights reserved.

58

Handbook of Nanomaterials in Analytical Chemistry

and SBSE are now very popular and applied to various sample matrices, that is, environmental, biological, medical, clinic samples, and so on [2 4,8]. It is undoubtable that extraction is one of the most commonly used sample preparation processes. It allows for complete isolation of an analyte, enriching of its concentration, exchanging of the matrix, and eliminating of interfering compounds. SPE is a classic and very frequently used sample preparation method. It can be implemented in manual, semiautomatic, or automatic ways. In the automatic case, online mode of SPE coupling with instrument (chromatography or capillary electrophoresis) can be implemented. Compared with LLE, the amount of organic solvent used in SPE is less and the emulsion formation during the extraction is disappeared [2], and can be easily semi-automated and coupled with chromatographic techniques. However, SPE requires laboratories and extensive preparatory procedures that introduce potential sources of error to the results. The cartridge batch repeatability is also the main problem. Moreover, the elution solvent must be concentrated by evaporation, for example, nitrogen blowing. The current trend in the analytical process is focused on the reducing organic solvent consumption, preventing from sample components degradation and eliminating addition sample pre- and postpreparation steps. Fortunately, new SPME methods, such as SPME, SBSE, and MSPD, have gained popularity in recent years and stimulated the development of new and improved sorption materials. As sorbent-based sample preparation methods, C18, C8, Florisil, hydrophilic lipophilic balance (HLB), mixed-mode/cationic exchange (MCX), mixedmode/anion exchange (MAX), weak cation exchange (WCX), and weak anion exchange (WAX) are the classic sorbents for SPE and MSPD, polydimethylsiloxane (PDMS) is the classic sorbent for SPME and SBSE. However, many kinds of nanomaterials for the above methods emerge very rapidly, such as carbon nanomaterials [carbon nanotubes (CNTs), nanocones, nanodisks and nanofibers, graphene (G), and graphene oxide (GO)], molecularly imprinted polymers (MIPs), metallic nanoparticles, and metal-organic frameworks (MOFs). These solid sorbents are described in detail in our previous review [8]. Here, it is not possible to give a comprehensive overview of all applications and we restrict the application overview to an introduction of the application of these sorbents in SPE, SPME, MSPD, and SBSE.

4.2

The application of nanomaterials in sample preparation

4.2.1 Solid-phase extraction Sample preparation using SPE was first introduced in the mid-1970s. It included multiple steps such as sample loading, rinsing, eluting, and so on. As a traditional extraction method, both the offline and at/on/in in of SPE is still being used and developed. On the basis of the principle of SPE, some new modes such as

Recent advances in solid-phase extraction techniques with nanomaterials

59

dispersive solid-phase extraction (dSPE), magnetic solid-phase extraction (mSPE) are also developed in recent years. As mentioned above, the sorbents such as C18, C8, Florisil, HLB, MCX, MAX, WCX, and WAX are commonly used. However, the major drawback of these sorbents is the low selectivity for different kinds of analytes. Combined with the current analytical demand for fast, integrated analytical platforms for analytes, novel nanoscale sorbents are more and more used recently, including carbon nanomaterials, MIPs, and so on. Table 4.1 listed some interesting examples of nanomaterial applied in SPE. MIPs have proven to be useful materials because of its specific selectivity for target analytes. Because MIPs are synthetic materials with artificially generated recognition sites able to specifically rebind a target molecule in preference to other closely related compounds, MIP-based SPE can provide perfect selective extraction efficiency. Therefore, many researches are focused on the MIPs synthesis as the sorbents of SPE. Fortunately, MIPs show excellent adsorption of various analytes in environment, food, and biological samples [15 18,38]. The carbon nanomaterials including CNTs, nanocones, nanodisks, and nanofibers, G and GO are more and more used in sample preparation because of their large adsorption surface-to-volume ratios and high affinity. For example, singlewall carbon nanotubes and multiwall carbon nanotubes (MWCNTs), G and GO are the popular alternatives for many researches [20 22,25]. Moreover, the combination of carbon nanomaterials is also the common selection for sample preparation [34]. Carbon nanomaterials combined with other nanomaterials are now another popular alternative sorbent in sample preparation. For example, MIP-coated magnetic graphene oxide (MIPs-GO) as the sorbents for SPE [38]. Owing to its high surface area and selectivity, MIPs-GO has successfully extracted and enriched phthalate esters in water samples. Another example is the combination of G modified on MOF-199 [30]. This is due to the presence of MOF-199 which leads to improved adsorption capacity, and the presence of G on the surface of MOF-199 which enhances the interaction with PAHs. There are also some other interesting sorbents used for various sample extraction. Tan et al. applied highly porous MOFs of type MIL-101(Cr) as the sorbent to extract estrogens [31]. The sorbent was packed into a micro-SPE device and estrogens were extracted from the genuine water samples. Under the most favorable conditions, the limits of detection (LODs) are between 0.95 and 23 ng L21. Relative recoveries ranged between 85.4% and 120.8%. Vakh et al. developed a novel approach for green and simple SPE of ionizable analytes using cation-exchange resin particles packed in a rotating cotton-based disk [42]. The cation-exchange resin provided effective separation of analyte from complex sample matrices and its elution by aqueous electrolyte solution without any organic solvents. Moreover, the disk promoted high mass transfer of the analyte to the cation-exchange resin surface and the resin surface to the elution solution. Some nanomaterials are also used to extract heavy metals. For example, zwitterionfunctionalized polymer microspheres have been used as the sorbent for the selective and rapid enrichment of mercury species in environmental waters by online SPE [43]. The LODs of 0.78, 0.63, and 0.49 ng L21 were reached for inorganic mercury,

Table 4.1 Novel nanomaterials applied in solid-phase extraction. Analytes

Nanomaterials

SPE mode

Analysis technique

Sample

LOD (ng mL21)

Ref.

Phthalic acid esters Chromium species

MOF Carboxyl-groupfunctionalized mesoporous silica Cationic gemini surfactant -resorcinol-aldehyde resin Core shell MFe2O4-TiO2 (M 5 Mn, Fe, Zn, Co, or Ni) nanoparticles Diglycolamide-grafted Fe3O4/polydopamine nanomaterial MIPs

dSPE dSPE

LC-MS ICP-MS

Water Water

0.022 0.069 0.022 0.069

[9] [10]

dSPE

HPLC-UV

Chopsticks

0.2 1.2 mg kg21

[11]

dSPE

ICP-OES

None

mSPE

ICP-OES

Water

0.039 0.425

[13]

SPE

UPLC-MS

Oral fluid

0.03 1.3

[14]

MIPs MIPs MIPs

dSPE SPE SPE

HPLC-DAD SERS UPLC-MS/MS

0.003 1.2 0.02 0.6

[15] [16] [17]

MIPs Electrospun nanofibrous membranes GO

mSPE SPE

HPLC-UV MFS

Water Apple juice Sodium chloride injection (0.9%), glucose injection (5%), soybean milk and pacifier Biscuit samples Water

1.3 None

[18] [19]

mSPE

UV Vis

0.017

[20]

Endocrine-disrupting compounds UO221 and some metal ions Rare earth elements

Amphetamine-type stimulants Bisphenol A Atrazine Eight bisphenols

Acrylamide Estriol Nitrite

Water, vegetable, soil, and sausage

[12]

Ni (II) Phenols

GO Graphene aerogels

Plant growth regulators Endocrine-disrupting compounds α1A-AR antagonists Phthalate esters

Triazine herbicides Microcystins Organochlorine pesticides Polycyclic aromatic hydrocarbons Estrogens Neonicotinoid insecticides Rare earth elements Paracetamol and caffeine Trans-resveratrol

AAS HPLC-UV

Water Water

0.70 0.016 0.075

[21] [22]

GO

SPE In-syringe SPE mSPE

HPLC-MS/MS

Fresh vegetables

0.089 0.015

[23]

Mesoporous silica

mSPE

HPLC-DAD

Food contact materials

1.0 2.5

[24]

CNs

dSPE

HPLC-UV

800

[25]

N-Co@carbon dodecahedron/ hierarchical carbon MOF Activated charcoal γ-Cyclodextrin polymer Fe3O4-NH2@MIL-101(Cr) MOF Graphene-modified copper-based MOF MIL-101(Cr)

dSPE

HPLC-UV

Traditional Chinese medicine Water and plastic packaged drinks

0.023 0.113

[26]

mSPE mSPE mSPE

HPLC-DAD HPLC-MS/MS GC-ECD

Milk and rice samples Water Soil

0.02 0.05 0.0008 0.002 0.15 0.28

[27] [28] [29]

dSPE

GC-FID

Water

0.003 0.01

[30]

UPLC-MS/MS

Water

0.00095 0.023

[31]

Zeolitic imidazolate MOF

Micro-SPE device mSPE

HPLC-MS/MS

Water

0.03 0.3

[32]

ZnFe2O4 nanotubes GO/MWCNTs/Fe3O4/SiO2

dSPE mSPE

ICP-MS HPLC-UV

Water, tea leaf, human hair Urine and wastewater

0.00001 0.00075 1.48 3.32

[33] [34]

Alendronate sodium grafted mesoporous magnetic nanoparticle

mSPE

HPLC-UV

Peanut oils

0.3

[35]

(Continued)

Table 4.1 (Continued) Analytes

Nanomaterials

SPE mode

Analysis technique

Sample

LOD (ng mL21)

Ref.

Tetrabromobisphenol A and 4-nonylphenol Triazine herbicides Phthalate esters Folic acid Salvianolic acids

Polyamidoamine dendrimer decorated Fe3O4 nanoparticle MIPs-gold nanoparticles MIPs-GO PDMS-MIPs Cucurbit [6] uril pseudorotaxane complexes immobilized on Silica nanoparticles SiO2@NiO

mSPE

HPLC-UV

Water

0.011 0.017

[36]

dSPE mSPE dSPE mSPE

HPLC-MS/MS GC-MS HPLC-UV HPLC-UV

Rice and wheat Water Orange juice Danshen samples

0.02 0.05 0.01 0.2 3 10 none

[37] [38] [39] [40]

SPE

HPLC-MS

Pig serum

none

[41]

Cation-exchange resin

Disk SPE

HPLC-UV

Human urine and serum

3 3 1028 mol L21

[42]

Zwitterion-functionalized polymer microspheres

SPE

HPLC ICP-MS

Water

0.00078

[43]

Benzimidazoles and related metabolites Ofloxacin Mercury speciation

AAS, atomic absorption spectrometry; GC-ECD, gas chromatography-electron capture detector; GC-FID, gas chromatography-fire ionization detector; GC-MS, gas chromatography mass spectrometry; HPLC-DAD, high-performance liquid chromatography-diode array detector; HPLC-MS/MS, high-performance liquid chromatography mass spectrometry/mass spectrometry; HPLCUV, high-performance liquid chromatography-ultraviolet; ICP-OES, inductively coupled plasma-optical emission spectrometry; MFS, molecular fluorescence spectrometry; UPLC-MS, ultra-high performance liquid chromatography mass spectrometry.

Recent advances in solid-phase extraction techniques with nanomaterials

63

methylmercury, and ethylmercury, respectively. Under the optimized conditions, the enrichment factors are up to 105 and 98 for inorganic and organic mercury, respectively.

4.2.2 Solid-phase microextraction In 1990 a breakthrough in sample preparation was achieved by the introduction of SPME [44], leading to a solvent-free sample preparation. Using an externally coated fiber, extraction of organic compounds could be performed by immersing the fiber in (mostly aqueous) liquid samples (immersion SPME) or by exposing the fiber to the headspace of a solid or liquid sample (headspace-SPME, HS-SPME) [45]. After the analytes have been extracted, they are eluted from the extraction phase via thermal, liquid, or laser desorption and typically injected into the liquid chromatography (LC), gas chromatography (GC), and capillary electrophoresis (CE), and so on. This technology has several advantages. First, SPME only use of a small amount of extraction phase, which is typically immobilized on a solid support. Small molecular analytes and very polar solutes (log Kow . 5) can be collected or enriched in sorbent of SPME [45,46]. Second, various compounds including non-volatile, semi-volatile, and/or volatile compounds can be collected because of the immersion-SPME and headspace-SPME modes. Third, during the extraction process, and aside from some exceptions, SPME devices do not require the use of solvents or additives. Therefore, SPME has widely spread into analytical field worldwide through the development and implementation of new SPME configurations, geometries, coatings, online SPME devices, and so on. When considering an SPME method, the following features of coating are advised to consider: coating chemistry, chemical binder, and coating thickness, substrate material (i.e., plastic, metal, wood, and paper). Current trends are focused on the development of novel sorbent coatings and formats (e.g., thin film) for SPME, new approaches (e.g., cold fiber and vacuum SPME), and the development of onsite devices to be used as passive samplers [47]. Commercially available SPME fibers, such as PDMS, divinylbenzene (DVB)/ carboxen (CAR)/PDMS and PDMS/DVB have been successfully used to organic analytes extraction in the past years [48 53]. The use of new SPME coatings based on metal nanoparticles, silica nanoparticles, MOFs, carbon nanomaterials, TiO2, a combination of organic/inorganic composite, ion liquid, MIPs, or conjugated microporous polymers is one of the most profiler research trends of SPME technology (see Table 4.2) [54 65]. Automation enables large reductions in time for both method development as well as during routine analysis, providing higher sample throughput and improving reproducibility [66]. Recently, the commonly used automation SPME online was introduced by Gerstel GmbH (Mulheim an der Ruhr, Germany) in the form of the MultiPurpose Sampler (MPS 2). High-throughput sample analysis was further improved in recent years. For example, Khaled et al. developed a fully automated 96-well SPME method coupled with ultra-high performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLCMS/MS) [67]. A HLB/polyacrylonitrile extraction phase was synthesized via

Table 4.2 Novel nanomaterials applied in solid-phase microextraction. Analytes

Nanomaterial

Analysis technique

Sample

LOD (ng L21)

Ref.

Benzene, toluene, ethylbenzene, and xylene Polycyclic aromatic hydrocarbons Polycyclic aromatic hydrocarbons Polycyclic aromatic hydrocarbons Sterol and steroid hormones Estrogens

Porous copper foam

GC-FID

Water

120 410

[54]

Mesoporous carbon

GC-MS

Wastewater

1.6 10

[55]

Organic inorganic hybrid silica aerogel MOF

GC-FID

Water

1 30

[56]

GC-MS

Water

0.29 0.94

[57]

GO-MOF Poly(3,4-ethylenedioxythiophene)/ graphene Fe3O4@TiO2 @covalent organic frameworks Titania/hydroxyapatite (HAP/TiO2)

HPLC-UV SALDI-TOF MS GC-MS

Meat, egg yolk, vegetable Bovine serum, human serum or human urine Soil

3 5 1.30 2.50

[58] [59]

3 6

[60]

GC-MS

Snow sample, deionized water sample

40 100

[61]

Ionic liquid-based periodic mesoporous organosilica Polymeric ionic liquid-based SPME fiber MIPs

GC-MS

T. kotschyanus oil

None

[62]

GC-MS

Echinacea flower

None

[63]

HPLC-UV

Wastewater

210 800

[64]

NiFe2O4

ICP-MS

Seafood

0.007 0.018

[65]

Polychlorinated biphenyls Benzene, toluene, ethylbenzene, and xylenes Components of Thymus kotschyanus oil Echinacea flower volatile constituents Endocrine-disrupting compounds Heavy metals

GC-FID, gas chromatography-flame ionization detector; GC-MS, gas chromatography-mass spectrometry; ICP-MS, inductively coupled plasma-mass spectrometry; SALDI-TOF MS, surface-assisted laser desorption/ionization time-of-flight mass spectrometry.

Recent advances in solid-phase extraction techniques with nanomaterials

65

precipitation polymerization. Veterinary drugs in chicken muscle were extracted via direct immersion SPME and determined by UPLC-MS/MS. The developed method was validated according to the Food and Drug Administration guidelines, taking into account the Canadian maximum residue limits and the US maximum tolerance levels for veterinary drugs in meat. Method accuracy ranged from 80% to 120% for at least 73 compounds.

4.2.3 Stir-bar sorptive extraction SBSE was developed by Sandra and coworkers in 1999 [68]. SBSE has been developed nearly 20 years ago and was commercialized as Twister (Gerstel GmbH, Mulheim a/d Ruhr, Germany) very soon after its introduction. David et al. have reviewed comprehensively the two decades of SBSE in detail, including the principle, the desorption, the application to liquid, gas, solid, and in passive samples, the outlook, etc. [45]. Here we just have introduced some nanoscale sorbents applied to SBSE. PDMS is the commonly used sorbent for SBSE and there are four-dimensional PDME-coated stir bars that can be commercially obtained [45]. However, PDMS has its own limitation for polar analytes sorption because its sorption ability is excellent for nonpolar analytes. Over the past years, enormous efforts have been made to develop alternative phases for SBSE and to apply these in the extraction of polar solutes. Gilart et al. summarized an excellent overview of the SBSE coating such as PDMS-modified coating, monolithic coatings, and some other polymers coatings [69]. Here a nanomaterial coating will be summarized. Some novel nanomaterials such as 4-phenyl-1,2,3-triazole-functionalized SBA-15 sorbents for high-to-moderate polar phenols extraction [70], cyclododecane [71], carbon nanohorns [72], core shell SiO2/ZrO2 composite microspheres [73], p-naphtholbenzein (PNB)-modified etched poly(ether ether ketone) (PEEK) jacket [74], MOFs [75,76], MOFs-PEEK [77], CoFe2O4 @oleic acid magnetic nanoparticles [78], MMWCNTs [79], MIPs [80 82], montmorillonite-doped polypyrrole/ nylon-6 nanocomposite [83], and so on in environmental samples (wastewater, water, soil, coastal, and sand samples), food samples (orange peel and fish), and biological samples (urine, plasma, pork, and liver).

4.2.4 Matrix solid-phase dispersion MSPD is a unique sample preparation method that can be directly applied for semisolid, solid, and viscous samples. MSPD was first introduced by Barker et al. in 1989 [84]. Different with SPE, in which separated solvent extraction procedure is required to make solid samples suitable for loading into a SPE column, MSPD do not need the solvent extraction step. In MSPD, samples can be blend with sorbents directly to obtain homogeneous mixture, then the mixture is transferred and packed in the SPE cartridge and is washed and eluted with liquid solvents. Therefore, MSPD eliminates steps of pretreatment such as centrifugation and filtration. Hoff et al. described the MSPD fundamentals in detail [85]. Tu et al. have reviewed the principles, sorbents, and the miniaturization of MSPD, discussing the progress in

66

Handbook of Nanomaterials in Analytical Chemistry

both micro-MSPD and mini-MSPD [86]. This review focused on the latest development in MSPD sorbent, including molecularly imprinted polymers, and carbon-based nanomaterials. In fact, the commonly used sorbents were C18 [87 89] or modified C18 [90], Florisil [91], sand [92], Diol [93], chitosan [94], and so on. Recently, more and more nanomaterials are applied to MSPD methods. For example, molecular-sieve-based sorbent such as carbon molecular sieve, MCM-41 and MCM-48 are popular. Du et al. used carbon molecular sieve to extract polyphenols in pomegranate peel [95]. Under the optimized conditions, satisfactory results were obtained for the extraction of gallic acid, punicalagin A, punicalagin B, catechin, and ellagic acid from pomegranate peel sample. Another examples were MCM-41 and MCM-48 mesoporous materials as sorbents in MSPD [96]. The MCM-41 and MCM-48 mesoporous materials were tested for extraction of pesticides in soursop fruit. The detection and quantification limits for the pesticides studied were in the ranges of 0.02 0.06 and 0.05 0.10 mg kg21. Also, the extraction efficiency of MCM-41 and MCM-48 were compared with Florisil. A similar performance was revealed. MIPs, as important nanomaterials, are also applied in MSPD. Gholami et al. developed a MIP-MSPD method to extract parabens from powder sunscreen samples. Under an optimized condition, the developed MIP-MSPD method exhibited wide linear range, low LODs, and excellent repeatability. Also, MOF-MIP is also very popular in MSPD [97,98]. For example, Wang et al. prepared MOF-MIP to extract tetracyclines from milk powder. Under the optimal conditions, the detection limits of tetracyclines were 0.217 0.318 ng g21. The method was successfully applied to the determination of tetracyclines in milk powder.

4.3

Conclusion

Nanomaterials are the major trends oriented to sample preparation sorbents because of their high selectivity, good sorptive/adsorptive capacity, enhanced thermal, chemical or mechanical stability, and improved lifetime of devices using them as sorbent/adsorbent media. Although many materials such as carbon nanomaterials, MIPs, MOFs, silica-based nanoparticles, and magnetic nanoparticles are more and more used, high selectivity and enrichment capability materials are still required. Significantly, vigorously developing the combined two or three or even more kind of nanomaterials together (MIP-MOF, MIP-MWCNTs, Fe3O4@TiO2@MOF, GO-MIP, etc.) can make rapid advancement of the materials, that is, higher adsorptive capacity, higher selectivity, rapid separation from the sample matrix, and so on. More excellent nanomaterials are demanding for various sample matrices, especially for food and biological samples. Moreover, compared with SPE and SPME, the sorbents development in SBSE and MSPD is less. Therefore, more and more application of nanomaterials in SBSE and MSPD should be developed in the future.

Recent advances in solid-phase extraction techniques with nanomaterials

67

Acknowledgment Financial support from the National Natural Science Foundation of China (no. 81660355) and the Colleges and Universities Scientific Research Projects of the Education Department of Hainan Province (Hnky2018ZD-8) are gratefully acknowledged.

References [1] D. Wianowska, M. Gil, New insights into the application of MSPD in various fields of analytical chemistry, TrAC Trends Anal. Chem. 112 (2019) 29 51. [2] Z. Niu, W. Zhang, C. Yu, J. Zhang, Y. Wen, Recent advances in biological sample preparation methods coupled with chromatography, spectrometry and electrochemistry analysis techniques, TrAC Trends Anal. Chem. 102 (2018) 123 146. [3] Y. Wen, J. Li, J. Ma, L. Chen, Recent advances in enrichment techniques for trace analysis in capillary electrophoresis, Electrophoresis 33 (2012) 2933 2952. [4] T. Baciu, F. Borrull, C. Aguilar, M. Calull, Recent trends in analytical methods and separation techniques for drugs of abuse in hair, Anal. Chim. Acta 856 (2015) 1 26. [5] D. Han, K.H. Row, Trends in liquid-phase microextraction, and its application to environmental and biological samples, Microchim. Acta 176 (2011) 1 22. [6] Z. Huang, H.K. Lee, Materials-based approaches to minimizing solvent usage in analytical sample preparation, TrAC Trends Anal. Chem. 39 (2012) 228 244. [7] S.K. Kailasa, V.N. Mehta, H.F. Wu, Recent developments of liquid-phase microextraction techniques directly combined with ESI- and MALDI-mass spectrometric techniques for organic and biomolecule assays, RSC Adv. 4 (2014) 16188 16205. [8] Y. Wen, L. Chen, J. Li, D. Liu, L. Chen, Recent advances in solid-phase sorbents for sample preparation prior to chromatographic analysis, TrAC Trends Anal. Chem. 59 (2014) 26 41. ´ . Gonza´lez-Curbelo, J. Herna´ndez-Borges, M.A ´ . Rodrı´guez[9] J. Gonza´lez-Sa´lamo, M.A Delgado, Use of Basolites F300 metal-organic framework for the dispersive solid-phase extraction of phthalic acid esters from water samples prior to LC-MS determination, Talanta 195 (2019) 236 244. [10] Q.Y. Zhu, L.Y. Zhao, D. Sheng, Y.J. Chen, X. Hu, H.Z. Lian, et al., Speciation analysis of chromium by carboxylic group functionalized mesoporous silica with inductively coupled plasma mass spectrometry, Talanta 195 (2019) 173 180. [11] S. Zhang, T. Xu, Q. Liu, J. Liu, F. Lu, M. Yue, et al., Cationic gemini surfactantresorcinol-aldehyde resin and its application in the extraction of endocrine disrupting compounds from food contacting materials, Food Chem. 277 (2019) 407 413. [12] L. Bian, J. Nie, X. Jiang, M. Song, F. Dong, L. Shang, et al., Selective adsorption of uranyl and potentially toxic metal ions at the core-shell MFe2O4-TiO2 (M 5 Mn, Fe, Zn, Co, or Ni) nanoparticles, J. Hazard. Mater. 365 (2019) 835 845. [13] F. Li, A. Gong, L. Qiu, W. Zhang, J. Li, Z. Liu, Diglycolamide-grafted Fe3O4/ polydopamine nanomaterial as a novel magnetic adsorbent for preconcentration of rare earth elements in water samples prior to inductively coupled plasma optical emission spectrometry determination, Chem. Eng. J. 361 (2019) 1098 1109.

68

Handbook of Nanomaterials in Analytical Chemistry

[14] A. Sorribes-Soriano, F.A. Esteve-Turrillas, S. Armenta, P. Amoro´s, J.M. HerreroMartı´nez, Amphetamine-type stimulants analysis in oral fluid based on molecularly imprinting extraction, Anal. Chim. Acta 1052 (2019) 73 83. [15] Y. Liu, D. Wang, F. Du, W. Zheng, Z. Liu, Z. Xu, et al., Dummy-template molecularly imprinted micro-solid-phase extraction coupled with high-performance liquid chromatography for bisphenol A determination in environmental water samples, Microchem. J. 145 (2019) 337 344. [16] B. Zhao, S. Feng, Y. Hu, S. Wang, X. Lu, Rapid determination of atrazine in apple juice using molecularly imprinted polymers coupled with gold nanoparticlescolorimetric/SERS dual chemosensor, Food Chem. 276 (2019) 366 375. [17] J. Zhang, Y. Chen, W. Wu, Z. Wang, Y. Chu, X. Chen, Hollow porous dummy molecularly imprinted polymer as a sorbent of solid-phase extraction combined with accelerated solvent extraction for determination of eight bisphenols in plastic products, Microchem. J. 145 (2019) 1176 1184. [18] A.R. Bagheri, M. Arabi, M. Ghaedi, A. Ostovan, X. Wang, J. Li, et al., Dummy molecularly imprinted polymers based on a green synthesis strategy for magnetic solid-phase extraction of acrylamide in food samples, Talanta 195 (2019) 390 400. [19] A.D.S. Nectoux, L.F. Medeiros, R.D.S. Bussamara Rodrigues, R.M. Duarte Soares, A. N. Fernandes, Electrospun nanofibrous membranes for solid-phase extraction of estriol from aqueous solution, J. Appl. Poly. Sci. 136 (2019) 47189 47197. [20] R. Nayebi, G.D. Tarigh, F. Shemirani, Electrostatically in situ binding of zwitterionic glycine on the surface of MGO for determination of nitrite in various real samples, Food Chem. 276 (2019) 255 261. [21] M.H. Kojidi, A. Aliakbar, Synthesis of graphene oxide-based poly(p-aminophenol) composite and its application in solid phase extraction of trace amount of Ni(II) from aquatic samples, Environ. Monit. Assess. 191 (2019) 145 157. [22] S. Tang, J. Sun, D. Xia, B. Zang, Y. Gao, C. Chen, et al., In-syringe extraction using compressible and self-recoverable, amphiphilic graphene aerogel as sorbent for determination of phenols, Talanta 195 (2019) 165 172. [23] S. Cao, J. Chen, G. Lai, C. Xi, X. Li, L. Zhang, et al., A high efficient adsorbent for plant growth regulators based on ionic liquid and beta-cyclodextrin functionalized magnetic graphene oxide, Talanta 194 (2019) 14 25. [24] J. Liu, X. Ma, S. Zhang, T. Wu, H. Liu, M. Xia, et al., Cationic gemini surfactant templated magnetic cubic mesoporous silica and its application in the magnetic dispersive solid phase extraction of endocrine-disrupting compounds from the migrants of food contact materials, Microchem. J. 145 (2019) 606 613. [25] Q. Hu, Y. Bu, X. Zhen, K. Xu, R. Ke, X. Xie, et al., Magnetic carbon nanotubes camouflaged with cell membrane as a drug discovery platform for selective extraction of bioactive compounds from natural products, Chem. Eng. J. 364 (2019) 269 279. [26] Y. Wang, Y. Tong, X. Xu, L. Zhang, Developed magnetic multiporous 3D N-Co@C/ HCF as efficient sorbent for the extraction of five trace phthalate esters, Anal. Chim. Acta 1054 (2019) 176 183. [27] N.I. Mohd, K. Gopal, M. Raoov, S. Mohamad, N. Yahaya, V. Lim, et al., Evaluation of a magnetic activated charcoal modified with non-ionic silicone surfactant as a new magnetic solid phase extraction sorbent with triazine herbicides as model compounds in selected milk and rice samples, Talanta 196 (2019) 217 225. [28] C. Huang, Y. Wang, Q. Huang, Y. He, L. Zhang, Magnetic γ-cyclodextrin polymer with compatible cavity promote the magnetic solid-phase extraction of microcystins in water samples, Anal. Chim. Acta 1054 (2019) 38 46.

Recent advances in solid-phase extraction techniques with nanomaterials

69

[29] X. He, Y. Zhou, W. Yang, S. Li, T. Liu, T. Wang, et al., Microwave assisted magnetic solid phase extraction using a novel amino-functionalized magnetic framework composite of type Fe3O4-NH2@MIL-101(Cr) for the determination of organochlorine pesticides in soil samples, Talanta 196 (2019) 572 578. [30] A. Amiri, F. Ghaemi, B. Maleki, Hybrid nanocomposites prepared from a metalorganic framework of type MOF-199(Cu) and graphene or fullerene as sorbents for dispersive solid phase extraction of polycyclic aromatic hydrocarbons, Microchim. Acta 186 (2019) 131 139. [31] S.C. Tan, H.K. Lee, A metal-organic framework of type MIL-101(Cr) for emulsification-assisted micro-solid-phase extraction prior to UHPLC-MS/MS analysis of polar estrogens, Microchim. Acta 186 (2019) 165 174. [32] Y. Qi, X. Cao, A.M. Abd El-Aty, C. Ma, H. Li, Z. Jiang, et al., A magnetic zeolitic imidazolate framework nanohybrid for fast and efficient extraction of clothianidin, imidacloprid, acetamiprid, and thiacloprid in water, J. Nanosci. Nanotechnol. 19 (2019) 3310 3318. [33] S. Chen, J. Yan, J. Li, D. Lu, Magnetic ZnFe2O4 nanotubes for dispersive micro solidphase extraction of trace rare earth elements prior to their determination by ICP-MS, Microchim. Acta 186 (2019) 228 235. [34] H.˙I. Ulusoy, E. Yılmaz, M. Soylak, Magnetic solid phase extraction of trace paracetamol and caffeine in synthetic urine and wastewater samples by a using core shell hybrid material consisting of graphene oxide/multiwalled carbon nanotube/Fe3O4/SiO2, Microchem. J. 145 (2019) 843 851. [35] Q. Zhao, D.Q. Cheng, M. Tao, W.-J. Ning, Y.-J. Yang, K.-Y. Meng, et al., Rapid magnetic solid-phase extraction based on alendronate sodium grafted mesoporous magnetic nanoparticle for the determination of trans-resveratrol in peanut oils, Food Chem. 279 (2019) 187 193. [36] Y. Wu, C. Chen, Q. Zhou, Q.X. Li, Y. Yuan, Y. Tong, et al., Polyamidoamine dendrimer decorated nanoparticles as an adsorbent for magnetic solid-phase extraction of tetrabromobisphenol A and 4-nonylphenol from environmental water samples, J. Colloid Interf. Sci. 539 (2019) 361 369. [37] M. Yan, Y. She, X. Cao, J. Ma, G. Chen, S. Hong, et al., A molecularly imprinted polymer with integrated gold nanoparticles for surface enhanced Raman scattering based detection of the triazine herbicides, prometryn and simetryn, Microchim. Acta 186 (2019) 143 152. [38] L. Guo, X. Ma, X. Xie, R. Huang, M. Zhang, J. Li, et al., Preparation of dual-dummytemplate molecularly imprinted polymers coated magnetic graphene oxide for separation and enrichment of phthalate esters in water, Chem. Eng. J. 361 (2019) 245 255. [39] A. Zengin, M. Utku Badak, M. Bilici, Z. Suludere, N. Aktas, Preparation of molecularly imprinted PDMS elastomer for selective detection of folic acid in orange juice, Appl. Surf. Sci. 471 (2019) 168 175. [40] Q. Zhang, D.-D. Zhou, J.-W. Zhang, D. Gao, F.-Q. Yang, H. Chen, et al., Aminoterminated supramolecular cucurbit [6] uril pseudorotaxane complexes immobilized on magnetite@silica nanoparticles: A highly efficient sorbent for salvianolic acids, Talanta 195 (2019) 354 365. [41] F. Zheng, H.M. Xiao, Q.F. Zhu, Q.W. Yu, Y.Q. Feng, Profiling of benzimidazoles and related metabolites in pig serum based on SiO2@NiO solid-phase extraction combined precursor ion scan with high resolution orbitrap mass spectrometry, Food Chem. 284 (2019) 279 286.

70

Handbook of Nanomaterials in Analytical Chemistry

[42] C. Vakh, M. Alaboud, S. Lebedinets, A. Bulatov, A rotating cotton-based disk packed with a cation-exchange resin: separation of ofloxacin from biological fluids followed by chemiluminescence determination, Talanta 196 (2019) 117 123. [43] X. Jia, J. Zhao, H. Ren, J. Wang, Z. Hong, X. Zhang, Zwitterion-functionalized polymer microspheres-based solid phase extraction method on-line combined with HPLC ICP-MS for mercury speciation, Talanta 196 (2019) 592 599. [44] C.L. Arthur, J. Pawliszyn, Solid phase microextraction with thermal desorption using fused silica optical fibers, Anal. Chem. 62 (1990) 2145 2148. [45] F. David, N. Ochiai, P. Sandra, Two decades of stir bar sorptive extraction: a retrospective and future outlook, TrAC Trends Anal. Chem. 112 (2019) 102 111. [46] G.A. Go´mez-Rı´os, M.F. Mirabelli, Solid phase microextraction-mass spectrometry: metanoia, TrAC Trends Anal. Chem. 112 (2019) 201 211. [47] M. Llompart, M. Celeiro, C. Garcı´a-Jares, T. Dagnac, Environmental applications of solid-phase microextraction, TrAC Trends Anal. Chem. 112 (2019) 1 12. [48] T. Li, Y. Song, J. Xu, J. Fan, A hydrophobic deep eutectic solvent mediated sol-gel coating of solid phase microextraction fiber for determination of toluene, ethylbenzene and o-xylene in water coupled with GC-FID, Talanta 195 (2019) 298 305. [49] C. Cordero, A. Guglielmetti, B. Sgorbini, C. Bicchi, E. Allegrucci, G. Gobino, et al., Odorants quantitation in high-quality cocoa by multiple headspace solid phase microextraction: adoption of FID-predicted response factors to extend method capabilities and information potential, Anal. Chim. Acta 1052 (2019) 190 201. [50] Q. Hu, S. Liu, Y. Liu, Xa Fang, J. Xu, X. Chen, et al., Development of an on site detection approach for rapid and highly sensitive determination of persistent organic pollutants in real aquatic environment, Anal. Chim. Acta 1050 (2019) 88 94. [51] M. Ghidotti, D. Fabbri, C. Torri, Determination of linear and cyclic volatile methyl siloxanes in biogas and biomethane by solid-phase microextraction and gas chromatography-mass spectrometry, Talanta 195 (2019) 258 264. [52] X. Liu, J. Deng, J. Bi, X. Wu, B. Zhang, Cultivar classification of cloudy apple juices from substandard fruits in China based on aroma profile analyzed by HS-SPME/ GC-MS, LWT 102 (2019) 304 309. [53] R. Jiang, W. Lin, L. Zhang, F. Zhu, G. Ouyang, Development of a novel solid phase microextraction calibration method for semi-solid tissue sampling, Sci. Total Environ. 655 (2019) 174 180. [54] M. Ghani, S.M. Ghoreishi, S. Masoum, Highly porous nanostructured copper oxide foam fiber as a sorbent for head space solid-phase microextraction of BTEX from aqueous solutions, Microchem. J. 145 (2019) 210 217. [55] H. Jiang, X. Hu, Y. Li, J. Qi, X. Sun, L. Wang, et al., Large-pore ordered mesoporous carbon as solid-phase microextraction coating for analysis of polycyclic aromatic hydrocarbons from aqueous media, Talanta 195 (2019) 647 654. [56] Y. Tian, J. Feng, X. Wang, C. Luo, H. Maloko Loussala, M. Sun, An organic-inorganic hybrid silica aerogel prepared by co-precursor method for solid-phase microextraction coating, Talanta 194 (2019) 370 376. [57] X. Yang, J. Wang, W. Wang, S. Zhang, C. Wang, J. Zhou, et al., Solid phase microextraction of polycyclic aromatic hydrocarbons by using an etched stainless-steel fiber coated with a covalent organic framework, Microchim. Acta 186 (2019) 145. [58] R. Mirzajani, F. Kardani, Z. Ramezani, A nanocomposite consisting of graphene oxide, zeolite imidazolate framework 8, and a molecularly imprinted polymer for (multiple) fiber solid phase microextraction of sterol and steroid hormones prior to their quantitation by HPLC, Microchim. Acta 186 (2019) 129.

Recent advances in solid-phase extraction techniques with nanomaterials

71

[59] S. Huang, N. Ye, G. Chen, R. Ou, Y. Huang, F. Zhu, et al., A robust and homogeneous porous poly(3,4-ethylenedioxythiophene)/graphene thin film for high-efficiency laser desorption/ionization analysis of estrogens in biological samples, Talanta 195 (2019) 290 297. [60] Q. Wang, H. Wu, F. Lv, Y. Cao, Y. Zhou, N. Gan, A headspace sorptive extraction method with magnetic mesoporous titanium dioxide@covalent organic frameworks composite coating for selective determination of trace polychlorinated biphenyls in soils, J. Chromatogr. A 1572 (2018) 1 8. [61] F. Rahmani, A. Es-haghi, M.-R.M. Hosseini, A. Mollahosseini, Preparation and characterization of a novel nanocomposite coating based on sol-gel titania/hydroxyapatite for solid-phase microextraction, Microchem. J. 145 (2019) 942 950. [62] M. Piryaei, M.M. Abolghasemi, B. Karimi, Determination and analysis of volatile components from Thymus kotschyanus boiss with a new solid-phase microextraction fibre and microwave-assisted hydrodistillation by periodic mesoporous organosilica based on alkylimidazolium ionic liquid, Phytochem. Anal. 30 (2019) 193 197. [63] M. Kaya, M. Merdivan, P. Tashakkori, P. Erdem, J.L. Anderson, Analysis of Echinacea flower volatile constituents by HS-SPME-GC/MS using laboratory-prepared and commercial SPME fibers, J. Essent. Oil Res. 31 (2018) 91 98. [64] X. Wang, P. Huang, X. Ma, X. Du, X. Lu, Enhanced in-out-tube solid-phase microextraction by molecularly imprinted polymers-coated capillary followed by HPLC for endocrine disrupting chemicals analysis, Talanta 194 (2019) 7 13. [65] P. Zhou, R. Zheng, W. Zhang, W. Liu, Y. Li, H. Wang, et al., Development of an effervescent tablet microextraction method using NiFe2O4-based magnetic nanoparticles for preconcentration/extraction of heavy metals prior to ICP-MS analysis of seafood, J. Anal. Atomic Spectrom. 34 (2019) 598 606. [66] K. Gorynski, A critical review of solid-phase microextraction applied in drugs of abuse determinations and potential applications for targeted doping testing, TrAC Trends Anal. Chem. 112 (2019) 135 146. [67] A. Khaled, E. Gionfriddo, V. Acquaro, V. Singh, J. Pawliszyn, Development and validation of a fully automated solid phase microextraction high throughput method for quantitative analysis of multiresidue veterinary drugs in chicken tissue, Anal. Chim. Acta 1056 (2019) 34 46. [68] E. Baltussen, P. Sandra, F. David, C. Cramers, Stir bar sorptive extraction (SBSE), a novel extraction technique for aqueous samples: theory and principles, J. Microcolumn Sep. 11 (1999) 737 747. [69] N. Gilart, R.M. Marce´, F. Borrull, N. Fontanals, New coatings for stir-bar sorptive extraction of polar emerging organic contaminants, TrAC Trends Anal. Chem. 54 (2014) 11 23. [70] A. Tanimu, S.M.S. Jillani, A.A. Alluhaidan, S.A. Ganiyu, K. Alhooshani, 4-phenyl1,2,3-triazole functionalized mesoporous silica SBA-15 as sorbent in an efficient stir bar-supported micro-solid-phase extraction strategy for highly to moderately polar phenols, Talanta 194 (2019) 377 384. [71] Y.W. Huang, H.K. Lee, H.K. Shih, J.F. Jen, A sublimate sorbent for stir-bar sorptive extraction of aqueous endocrine disruptor pesticides for gas chromatography-electron capture detection, J. Chromatogr. A 1564 (2018) 51 58. [72] B. Fresco-Cala, S. Ca´rdenas, Nanostructured hybrid monolith with integrated stirring for the extraction of UV-filters from water and urine samples, Talanta 182 (2018) 391 395.

72

Handbook of Nanomaterials in Analytical Chemistry

[73] J. Li, H. Li, W. Zhang, Y. Wang, Q. Su, L. Wu, Hollow fiber stir bar sorptive extraction and gas chromatography mass spectrometry for determination of organochlorine pesticide residues in environmental and food matrices, Food Anal. Methods 11 (2018) 883 891. [74] W. Zhou, C. Wang, X. Wang, Z. Chen, Etched poly(ether ether ketone) jacket stir bar with detachable dumbbell-shaped structure for stir bar sorptive extraction, J. Chromatogr. A 1553 (2018) 43 50. [75] J.H. Yang, C.X. Cui, L.B. Qu, J. Chen, X.M. Zhou, Y.P. Zhang, Preparation of a monolithic magnetic stir bar for the determination of sulfonylurea herbicides coupled with HPLC, Microchem. J. 141 (2018) 369 376. [76] M. Ghani, S.M. Ghoreishi, M. Azamati, In-situ growth of zeolitic imidazole framework-67 on nanoporous anodized aluminum bar as stir-bar sorptive extraction sorbent for determining caffeine, J. Chromatogr. A 1577 (2018) 15 23. [77] C. Wang, W. Zhou, X. Liao, X. Wang, Z. Chen, Covalent immobilization of metal organic frameworks onto chemical resistant poly(ether ether ketone) jacket for stir bar extraction, Anal. Chim. Acta 1025 (2018) 124 133. [78] J.L. Benede, A. Chisvert, C. Moyano, D.L. Giokas, A. Salvador, Expanding the application of stir bar sorptive-dispersive microextraction approach to solid matrices: determination of ultraviolet filters in coastal sand samples, J. Chromatogr. A 1564 (2018) 25 33. [79] A.R. Zarei, M. Nedaei, S.A. Ghorbanian, Deep eutectic solvent based magnetic nanofluid in the development of stir bar sorptive dispersive microextraction: an efficient hyphenated sample preparation for ultra-trace nitroaromatic explosives extraction in wastewater, J. Sep. Sci. 40 (2017). Available from: https://doi.org/10.1002/ jssc.201700915. [80] J. Tang, J. Wang, S. Shi, S. Hu, L. Yuan, Determination of β-agonist residues in animal-derived food by a liquid chromatography-tandem mass spectrometric method combined with molecularly imprinted stir bar sorptive extraction, J. Anal. Methods Chem. 2018 (2018) 1 10. ´ lvarez, E. Turiel, A. Martı´n-Esteban, Molecularly imprinted polymer [81] M. Dı´az-A monolith containing magnetic nanoparticles for the stir- bar sorptive extraction of thiabendazole and carbendazim from orange samples, Anal. Chim. Acta 1469 (2016) 1 7. [82] T. Tang, F. Wei, X. Wang, Y. Ma, Y. Song, Y. Ma, et al., Determination of semicarbazide in fish by molecularly imprinted stir bar sorptive extraction coupled with high performance liquid chromatography, J. Chromatogr. B 1076 (2018) 8 14. [83] Z. Ayazi, M. Pourvali, A.A. Matin, Preparation of a novel stir bar coating based on montmorillonite doped polypyrrole/nylon-6 nanocomposite for sorptive extraction of organophosphorous pesticides in aqueous samples, Int. J. Environ. Anal. Chem. 98 (2018) 138 155. [84] S.A. Barker, A.R. Long, C.R. Short, Isolation of drug residues from tissues by solid phase dispersion, J. Chromatogr. A 475 (1989) 353 361. [85] R.B. Hoff, T.M. Pizzolato, Combining extraction and purification steps in sample preparation for environmental matrices: a review of matrix solid phase dispersion (MSPD) and pressurized liquid extraction (PLE) applications, TrAC Trends Anal. Chem. 109 (2018) 83 96. [86] X. Tu, W. Chen, A review on the recent progress in matrix solid phase dispersion, Molecules 23 (2018) 2767 2780.

Recent advances in solid-phase extraction techniques with nanomaterials

73

[87] M.C. Simeoni, M. Sergi, A. Pepe, E. Mattocci, G. Martino, D. Compagnone, Determination of free fatty acids in cheese by means of matri solid-phase dispersion followed by ultra-high performance liquid chromatography and tandem mass spectrometry analysis, Food Anal. Method. 11 (2018) 2961 2968. [88] G. Castro, I. Carpinteiro, I. Rodrı´guez, R. Cela, Determination of cardiovascular drugs in sewage sludge by matrix solid-phase dispersion and ultra-performance liquid chromatography tandem mass spectrometry, Anal. Bioanal. Chem. 410 (2018) 6807 6817. [89] A.A. Vieira, S.S. Caldas, L. Kupski, R.A. Tavella, E.G. Primel, Extraction of chlorothalonil, dichlofluanid, DCOIT, and TCMTB from fish tissues employing the vortex assisted matrix solid-phase dispersion, Microchem. J. 143 (2018) 92 98. [90] M. Ding, J. Li, S. Zou, G. Tang, X. Gao, Y. Chang, Simultaneous extraction and determination of compounds with different polarities from platycladi cacumen by AQ C18-based vortex-homogenized matrix solid-phase dispersion with ionic liquid, Front. Pharmacol. 9 (2019) 1532 1542. [91] Q. Luo, S. Wang, Y. Shan, L. Sun, H. Wang, Matrix solid-phase dispersion coupled with gas chromatography tandem mass spectrometry for simultaneous determination of 13 organophosphate esters in vegetables, Anal. Bioanal. Chem. 410 (2018) 7077 7084. [92] L. Rubio, J.P. Lamas, M. Lores, C. Garcia-Jares, Matrix solid-phase dispersion using limonene as greener alternative for grape seeds extraction, followed by GC-MS analysis for varietal fatty acid profiling, Food Anal. Methods 11 (2018) 3235 3242. [93] M. Ding, Y. Bai, J. Li, X. Yang, H. Wang, X. Gao, et al., A diol-based-matrix solid-phase dispersion method for the simultaneous extraction and determination of 13 compounds from angelicae pubescentis radix by ultra high-performance liquid chromatography, Front. Pharmacol. 10 (2019) 227 235. [94] W. Wu, W. Qian, H. Hao, Y. Kang, Y. Wang, Y. Deng, et al., Determination of caffeoylquinic acid derivatives in azolla imbricata by chitosan-based matrix solid-phase dispersion coupled with HPLC PDA, J. Pharmaceut. Biomed. Anal. 163 (2019) 197 203. [95] L.J. Du, J.P. Huang, B. Wang, C.H. Wang, Q.Y. Wang, Y.H. Hu, et al., Carbon molecular sieve based micro-matrix-solid-phase dispersion for the extraction of polyphenols in pomegranate peel by UHPLC-Q-TOF/MS, Electrophoresis 39 (2018) 2218 2227. [96] L.F.S. Santos, R.A. de Jesus, J.A.S. Costa, L.G.T. Gouveia, M.E. de Mesquita, S. Navickiene, Evaluation of MCM-41 and MCM-48 mesoporous materials as sorbents in matrix solid phase dispersion method for the determination of pesticides in soursop fruit (Annona muricata), Inorg. Chem. Commun. 101 (2019) 45 51. [97] S. Wang, J. Zhang, C. Li, L. Chen, Analysis of tetracyclines from milk powder by molecularly imprinted solid-phase dispersion based on a metal-organic framework followed by ultra high performance liquid chromatography with tandem mass spectrometry, J. Sep. Sci. 41 (2018) 2604 2612. [98] T. Liang, S. Wang, L. Chen, N. Niu, Metal organic framework-molecularly imprinted polymer as adsorbent in matrix solid phase dispersion for pyrethroids residue extraction from wheat, Food Anal. Method. 12 (2018) 217 228.

The use of magnetic nanoparticles in sample preparation devices and tools

5

˙ Ru¨stem Kec¸ili1, Sibel Bu¨yu¨ktiryaki1, Ibrahim Dolak2 and Chaudhery Mustansar Hussain3 1 Yunus Emre Vocational School of Health Services, Department of Medical Services and Techniques, Anadolu University, Eski¸sehir, Turkey, 2Vocational School of Technical Sciences, Dicle University, Diyarbakır, Turkey, 3Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, NJ, United States

5.1

Introduction

The sampling and sample preparation stages take almost two-third of the total time of the analytical processes [1]. These stages are also the main source of uncertanities in the analyses [2]. Thus researchers put so much effort in the development of facile, fast, low cost, efficient, selective, and environmentally friendly sample preparation techniques. The conventional sample preparation approaches such as liquid
liquid extraction have some drawbacks (i.e., time consuming, show low selectivity and efficiency toward the target compound/s, and high consumption of toxic organic solvents, etc.). To overcome these disadvantages of conventional techniques, new sample preparation techniques have been developed and successfully used for the analysis of environmental samples [3
10]. These techniques have many superiorities such as high selectivity for the target compound/s, facile automation, low cost, environmentally friendly, rapid processing of samples, high reproducibility, and the need of low volumes of organic toxic solvents. Nanoparticles are extensively applied in sample preparation processes [11
16]. They exhibit high surface-area-to-volume ratio, which promises a much higher capacity for extraction of target compound/s from complex matrices and efficiency compared with the other conventional adsorbents. In addition, the surface functionality of the nanoparticles can successfully be modified to achieve effective and selective extraction. Among various types of nanoparticles, magnetic nanoparticles are interesting advanced materials and have gained great attention among researchers from a wide range of disciplines in science [17
20]. Magnetic nanoparticles were successfully applied for different applications such as magnetic fluids [21], catalysis [22], magnetic resonance imaging [23], and environmental remediation [24,25]. As magnetic nanoparticles exhibit superparamagnetic feature that can be Handbook of Nanomaterials in Analytical Chemistry. DOI: https://doi.org/10.1016/B978-0-12-816699-4.00005-0 Copyright © 2020 Elsevier Inc. All rights reserved.

76

Handbook of Nanomaterials in Analytical Chemistry

attracted to a magnetic field, but retain no residual magnetism after the field is removed. Thus it is very easy to separate these magnetic nanoparticles adhered with target compound/s from complex matrices such as environmental, food, and biological samples by using an external magnetic field. There is no centrifugation or filtration step is needed during this process. However, an unavoidable drawback associated with these nanoparticles in this range of their size is instability of these magnetic nanoparticles, which tends to cause formation of agglomerates in the sample solution. Moreover, naked metallic nanoparticles are highly chemically active and can easily be oxidized in air that lead to loss of their dispersibility and magnetism feature. Therefore it is important to design and develop protection approaches for the chemical stabilization of the naked magnetic nanoparticles. These approaches for the modification of the surfaces of magnetic nanoparticle comprise grafting technique or coating with an inorganic layer such as carbon or silica or coating with organic compounds including polymers and surfactants [26]. This chapter provides an overview of the recent progresses on the design and development of new magnetic nanoparticles for the sample preparation processes. The chapter starts with the brief explanation of various techniques commonly used for the synthesis of magnetic nanoparticles. Then, solid-phase extraction (SPE) as the sample preparation tool is described. Finally, the recent SPE applications of magnetic nanoparticles for environmental, biological, food, and beverage samples are demonstrated.

5.2

Synthesis of magnetic nanoparticles

Researchers conducted a lot of studies on the synthesis of magnetic nanoparticles. There are various popular routes to obtain monodisperse, shape-controllable, and stable magnetic nanoparticles such as thermal decomposition, coprecipitation, sol
gel synthesis, hydrothermal synthesis, microemulsion, flow injection, and aerosol/vapor-phase-based synthesis techniques. To date, magnetic nanoparticles synthesized by applying thermal decomposition and coprecipitation approaches are the best studied types of the synthesis techniques of the magnetic nanoparticles.

5.2.1 Thermal decomposition technique Magnetic nanoparticles can successfully be synthesized by thermal decomposition of metal precursors including metal carbonyls such as Fe(CO)5, Co2(CO)8, and Ni (CO)4 and metal oleates in autoclaves or reactors by applying at high pressure and temperature during the synthesis process [27]. Thermal decomposition technique yields products having great monodispersity, excellent control in particle size, narrow size distribution, and excellent crystallinity of individual and dispersible iron oxide magnetic nanoparticles. The main drawbacks of this approach are the need for high temperature during the synthesis process, high cost, use of toxic organic solvents/chemicals, and the need for further modification to increase the

The use of magnetic nanoparticles in sample preparation devices and tools

77

biocompatibility of the synthesized magnetic nanoparticles (i.e., Fe3O4 nanoparticles) [28]. A number of magnetic metal nanoparticles were synthesized by applying this approach with the use of metal carbonyl precursors (i.e., Co2(CO)8 and Fe (CO)5) [29,30]. Magnetic metal nanoparticles (i.e., Ni and Co) can also easily be synthesized by decomposition of low-valent alkene or polyene metal complexes with H2 at room temperature [31,32]. Recently, water-soluble magnetic nanoparticles with controllable particle size and narrow size distribution were successfully synthesized. In a study carried out by Lee and coworkers [33], high-quality magnetismengineered iron oxide nanoparticles were prepared in the organic medium at high temperature. In this study, the authors successfully used the prepared high-quality magnetism-engineered iron oxide nanoparticles as contrast agents for the magnetic resonance applications and tested their applicability as molecular imaging probes for the sensitive recognition of target biomolecules. In another interesting work [34], Hu and colleagues developed a method of one-pot preparation of water-soluble magnetic nanoparticles at 245 C. The prepared magnetic nanoparticles were efficiently applied as magnetic resonance imaging contrast agents for cancer diagnosis.

5.2.2 Coprecipitation technique Coprecipitation technique is a facile and effective approach for the preparation of iron oxides with either γ-Fe2O3 or Fe3O4 structure. This technique is based on the chemical reactions occurring in an aqueous solution with the process of both nucleation and growth of iron hydroxide nuclei [35]. The coprecipitation process of Fe21/Fe31 salts is carried out at ambient temperature under alkaline conditions. The synthesis of magnetic iron oxide nanoparticles with suitable diameter, magnetic responsiveness, and surface properties can successfully be achieved by the optimization of experimental conditions (i.e., medium pH, temperature, ionic strength, and the molar ratio of reactants, etc.) [36]. The chemical reaction of the Fe3O4 synthesis can be expressed by Eq. (5.1). Fe21 1 2Fe31 1 8OH2 ! Fe3 O4 1 4H2 O

(5.1)

One of the main superiority of the coprecipitation approach is that magnetic iron oxide nanoparticles can successfully be obtained in large scale [37]. However, it needs the careful optimization of the reaction conditions and usually results in a rather broad size distribution of magnetic nanoparticles. The first successful synthesis of magnetic iron oxide nanoparticles was conducted by Massart and Cabuil under alkaline conditions by coprecipitation of FeCl2 and FeCl3 [38]. In their study, they prepared magnetic nanoparticles having B8 nm average diameter and were roughly spherical.

5.2.3 Sol
gel synthesis In the sol
gel synthesis of the magnetic nanoparticles, the hydroxylation and condensation of the reactants in solutions are used to obtain a sol of nanoparticles.

78

Handbook of Nanomaterials in Analytical Chemistry

In the next step, a gel with a three-dimensional network of metal oxide is prepared by the condensation as well as inorganic polymers of aerosol. Then, crystalline state is achieved by heating of the prepared gel [39]. The gel structure and its performance can easily be controlled by optimization of the conditions of hydroxylation and condensation process such as medium pH, temperature, solvent, and concentration of the salt precursors. [40]. This approach is facile, effective, and provides various advantages such as high reaction activity, good mixing uniformity, and low process temperature. However, the synthesized magnetic nanoparticles can be coagulated during posttreatment process.

5.2.4 Hydrothermal synthesis In the hydrothermal synthesis technique, the synthesis of magnetic nanoparticles is performed by using aqueous medium at high temperature and pressure [41]. Applying high temperature during the synthesis of magnetic nanoparticles is crucial and beneficial for the improvement of the nucleation rate and to speed up the growth of the new nanoparticles, which ensures to achieve small size of particles. Hydrolysis and oxidation are one of the many ways for the synthesis of magnetic nanoparticles under hydrothermal conditions and another way is neutralization of hybrid metal hydroxides.

5.2.5 Microemulsion-based synthesis A microemulsion is defined as a thermodynamically stable isotropic dispersion of two immiscible liquids in which the microdomain of either or both liquids was stabilized by an interfacial film of surface-active compounds [42]. Microemulsionbased synthesis is usually carried out by accomplishing the aforementioned chemical reactions such as coprecipitation or reduction in microemulsions to carefully control the size of the prepared magnetic nanoparticles. It is achieved by the reaction of either two reactants lying in two separate micellar systems through mixing and coalescence or reactants inside a single micelle through thermal initiation [43]. Monodisperse magnetic nanoparticles having various morphologies can be synthesized by applying microemulsion-based approach. The main disadvantages of this technique are high consumption of organic solvents during the production process of the magnetic nanoparticles and low production yield [44].

5.2.6 Flow injection synthesis Flow injection synthesis technique is another effective approach for the synthesis of magnetic nanoparticles having narrow size distribution. This technique is based on the segmented or continuous mixing of the chemical reagents by applying a laminar flow in a capillary reactor during the synthesis process of the magnetic nanoparticles. In a study reported by Alvarez and colleagues [45], magnetic Fe3O4 nanoparticles having a narrow size distribution varied in the range between 2 and 7 nm were successfully synthesized by applying this technique. Flow injection synthesis

The use of magnetic nanoparticles in sample preparation devices and tools

79

approach has various superiorities such as excellent mixing homogeneity and great reproducibility because of the laminar plug-flow conditions.

5.2.7 Aerosol/vapor-phase-based synthesis Aerosol-based techniques such as laser pyrolysis and spray approach are efficient techniques because of high rate synthesis in continuous chemical processes [46]. In spray pyrolysis technique, a solution composed of an organic reducing agent and ferric salts is sprayed into a series of reactors followed by condensing of the aerosol solute and evaporating the solvent. The obtained dried residues are transformed into magnetic nanoparticles. The size of these nanoparticles depends on the initial size of the droplet. On the other hand, laser pyrolysis technique is another promising approach that is applied for the preparation of magnetic nanoparticles. A laser heating a gaseous mixture of iron precursor such as iron pentacarbonyl is used to decrease the reaction time during the production process. The synthesis reaction is continuously carried out into generators to obtain high-yield magnetic nanoparticles. Laser pyrolysis technique is successfully applied for the synthesis of narrow size distributed, small and nonaggregated magnetic nanoparticles. Magnetic nanoparticles having the crystal size with a quite narrow size distribution in the range between 2 and 7 nm can effectively be prepared under optimum process conditions [47].

5.3

Solid-phase extraction

SPE is an efficient tool for the sample preparation in chemistry. SPE was first applied in 1940s [48], and the rapid progresses in various SPE applications were initiated in 1970s. It is now successfully applied in different fields of science. Conventional SPE materials such as silica-based [49], carbon-based [50], and claybased [51] resins were used in various SPE examples. Many adsorbents for SPE applications are now commercially available in different formats in the market such as SPE tubes and pipette tip formats such as Oasis-HLB (produced by Waters), Omix (produced by Agilent), and MonoTips (produced by GL Sciences). The basic principles of SPE are similar to liquid
liquid extraction. Both methods involve the distribution of dissolved species between two phases. However, SPE involves the dispersion of the analyte between a liquid (sample medium) and a solid (adsorbent) phase instead of the two liquid phases which cannot be not mixed together as in liquid
liquid extraction. This technique allows the enrichment and purification of the analytes on a solid adsorbent through adsorption from the solution.

5.4

Magnetic solid-phase extraction

Magnetic nanoparticles are interesting materials that are widely used in many application areas such as catalysis [52], separation [53,54], and drug delivery [55].

80

Handbook of Nanomaterials in Analytical Chemistry

Magnetic nanoparticles can easily be separated from the complex matrices such as biological and environmental samples by using an external magnetic field. Thus no filtration or centrifugation steps are required. Although magnetic nanoparticles exhibit excellent features, there are some drawbacks such as agglomeration of the particles and stability issues. Bare metallic nanoparticles are chemically very active and easily oxidized that lead to loss of their magnetic features. Thus these nanoparticles are needed to be coated with a layer (e.g., carbon, silica, or polymers) to protect their stability. Magnetic solid-phase extraction (MSPE) was proposed for the facile and fast sample preparation processes [56]. The magnetic materials are generally directly dispersed in the sample solutions for the rapid extraction process because they can be readily recovered by a magnet. It also overcomes the drawbacks with traditional SPE process such as eliminating the packing of columns and avoiding the timeconsuming process of loading large volume of samples. Typically, the MSPE material is composed of a core material such as Fe3O4 nanoparticles to be collected by using a magnet and a supported nanoparticle for the extraction of various target compounds from complex matrices (i.e., environmental samples, food and beverage samples, and biological samples).

5.4.1 Magnetic solid-phase extraction for environmental samples In recent years, several studies were reported on the application of MSPE for environmental samples using magnetic nanoparticles. For example, Haeri and Abbasi developed magnetic nanoparticles for the preconcentration of atrazine from water samples [57]. The results indicated that the analytical response of the prepared nanopacticles was linear over the range 0.1
50 μg L21 with limit of detection (LOD) 0.033 μg L21 by using high-performance liquid chromatography under optimized conditions. They obtained the enrichment factor as 268 for atrazine in their study. In another interesting study carried out by Dai and colleagues [58], magnetic Fe3O4/SiO2/dithiocarbamate nanoparticles were prepared for the efficient removal of Cu21 and Ni21 ions from aqueous solutions. The obtained results confirmed that the prepared magnetic Fe3O4/SiO2/dithiocarbamate nanoparticles exhibited excellent binding affinity toward the target ions. The binding capacity values for Cu21 and Ni21 ions were achieved as 230.49 and 235.23 mg g21, respectively. Sun and coworkers developed magnetic Fe3O4/ZrO2 nanoparticles for the effective removal of As (III) ions from water samples via photocatalytic oxidation process [59]. In their study, As (III) ions were completely oxidized to As (V) ions, which have less toxic feature by using the prepared magnetic Fe3O4/ZrO2 nanoparticles. As (V) ions were simultaneously adsorbed on the surface of the magnetic nanoparticles. The achieved maximum binding capacity was 133.48 mg g21. In a study reported by Soares et al. [60], diclofenac (DCF) was successfully removed from water samples by using a magnetic Fe3O4/SiO2/quaternary chitosan

The use of magnetic nanoparticles in sample preparation devices and tools

81

Figure 5.1 The schematic demonstration of the binding process of DCF to the magnetic Fe3O4/SiO2/quaternary chitosan nanocomposite. Source: Reproduced with permission from S.F. Soares, T. Fernandes, M. Sacramento, T. Trindade, A.L. Daniel-da-Silva, Magnetic quaternary chitosan hybrid nanoparticles for the efficient uptake of diclofenac from water, Carbohydr. Polym. 203 (2019) 35
44.

nanocomposite. Fig. 5.1 shows the schematic demonstration of the binding process of DCF to the magnetic Fe3O4/SiO2/quaternary chitosan nanocomposite. In this study, the maximum binding capacity was found as 240.4 mg g21. In an important study conducted by Ma and colleagues [61], magnetic ligninbased carbon nanoparticles were prepared by applying precipitation/carbonization approach. The prepared magnetic nanoparticles were successfully used for the efficient removal of methyl orange dye from aqueous solutions. The obtained maximum binding capacity was 113.0 mg g21. In another study [62], Golmohammadi and coworkers successfully removed reactive yellow 15 dye pollutants from water samples by using magnetic Fe3O4/ SiO2 nanoparticles functionalized with ionic liquid [3-(trimethoxysilylpropyl)] ammonium chloride. The obtained results indicated that the prepared magnetic nanoparticles exhibited high affinity toward the target dye compound. The binding capacity was achieved as 63.69 mg g21. On the other hand, molecularly imprinted polymers (MIPs) are efficiently utilized as solid-phase extraction materials (MISPEs) to decrease cumbersome sample preparation steps and facilitate selective isolation, sample purification, and preconcentration of chemical species. Application of MIPs, especially as MISPE extraction material, has been well researched for compounds including mycotoxins [63], sterols [64], various drugs [65], amide anesthetics [66], and organic dyes [67]. The majority of the MISPE studies indicated that MIPs are stable under strong elution conditions including a wide range of pH, different solvents, and various organic modifiers. In addition, a study by Pichon and colleagues confirmed that MIPs are more selective than C18 or ion-exchange materials, which are traditionally used in sample treatment methods like SPE, and are also more selective and stable than immunoextraction matrices [68].

82

Handbook of Nanomaterials in Analytical Chemistry

Among the various physical forms of MIPs such as monoliths, gels, membranes, spherical particles in micro- and nanoscale, molecularly imprinted nanoparticles have received great attention from the researchers because of their facile preparation, rapid recognition kinetics toward target compound/s [69]. Molecularly imprinted nanoparticles were successfully applied for the sensitive detection of pollutants in environmental samples. For example, in an interesting work carried out by Jiang and colleagues [70], ion-imprinted magnetic Fe3O4/SiO2 core-shell nanoparticles were prepared for the rapid and sensitive detection of methyl mercury (MeHg) in natural water samples. For this purpose, methacrylic acid (MAA) and trimethylolpropane trimethacrylate were preferred as the functional monomer and cross-linker, respectively. In this study, excellent detection limit was achieved (0.084 pg mL21) and the binding capacity of the prepared magnetic ion-imprinted magnetic nanoparticles for MeHg was obtained as 25 mg g21. In a study conducted by Hu and coworkers [71], MIP-based carboxylated cellulose nanocrystals were prepared for the selective separation of ofloxacin. The prepared MIP-based nanocrystals exhibited very fast binding kinetics toward the target compound ofloxacin and 34.09 mg g21 binding capacity was obtained in a short time (2 min). The selectivity studies were also performed using lomefloxacin, marbofloxacin, orbifloxacin, sulfamethoxazole, gatifloxacin, sarafloxacin, and difloxacin as competing fluoroquinolones. The maximum binding capacity was obtained as 40.65 mg g21 after 20 min. Patin˜o-Ropero et al. reported the application of magnetic molecularly imprinted core-shell nanoparticles for the efficient extraction of various triazines (i.e., atrazine, desethylatrazine, simazine, desisopropylatrazine, and propazine) from soil samples [72]. In this study, first, magnetic Fe3O4 nanoparticles having vinyl functional groups were synthesized. Then, propazine-imprinted thin layer was synthesized on the surface of magnetic nanoparticles using MAA and EGDMA as the functional monomer and cross-linker, respectively. The prepared magnetic molecularly imprinted core-shell nanoparticles were successfully applied for the extraction of target five different triazine pollutants from soil samples. The achieved LOD values varied between 0.1 and 3 ng g21. Qi and coworkers prepared ion-imprinted magnetic nanoparticles for the efficient and selective extraction of Cr (VI) ions from various environmental samples including lake water, river water, and tap water [73]. For this purpose, functional monomer vinylimidazole and comonomer 3-aminopropyltriethoxysilane were used for the preparation of ion-imprinted magnetic nanoparticles toward Cr (VI) ions. The effects of various factors including such as amount of nanoparticles, time, concentration, and the type of the eluent on the extraction of target Cr (VI) ions were investigated in details. The achieved results showed that the prepared ion-imprinted magnetic nanoparticles exhibited excellent selectivity toward target Cr (VI) ions over various cations and anions present in natural water samples. The detection limit was obtained as 0.29 μg L21 (Fig. 5.2). Barati and colleagues developed MIP-based magnetic graphene oxide (GO)/chitosan nanocomposite toward fluoxetine in biological and environmental samples [74].

The use of magnetic nanoparticles in sample preparation devices and tools

83

Figure 5.2 The schematic depiction of the removal of Cr (VI) ions from environmental water samples by using ion-imprinted magnetic nanoparticles. Source: Reproduced with permission from X. Qi, S. Gao, G. Ding, A-N. Tang, Synthesis of surface Cr (VI)-imprinted magnetic nanoparticles for selective dispersive solid-phase extraction and determination of Cr (VI) in water samples, Talanta 162 (2017) 345
353.

In their study, MIP-based magnetic GO/chitosan nanocomposite was prepared. The prepared MIP-based magnetic nanocomposite was successfully used for the selective separation of fluoxetine from urine and water samples. The maximum binding capacity was calculated as 66 mg g21. In another study reported by Wu and coworkers [75], bisphenol-A (BPA) was successfully extracted from water and fruit juice samples by using magnetic Fe3O4/SiO2 nanoparticles coated with MIP layer (Fig. 5.3). The prepared MIP-based magnetic nanoparticles showed great extraction efficiency toward the target compound BPA. In this study, the detection limit was achieved as 0.3 ng mL21. Hosseinzadegan et al. reported the design and preparation of silica-coated magnetic cobalt nanoparticles having ionic liquid layer for the selective extraction of Pb (II) ions from drinking water [76]. In their study, phosphonium-based ionic liquids with variable anions were chosen. Preliminary studies using various candidates indicated that the combination of trihexyltetradecylphosphonium cation ([P66614]1) and bis(2-ethylhexyl)phosphinate anion ([BEHPA]2) lead to better extraction of Pb (II) ions from aqueous solutions. The schematic depiction of the preparation of

84

Handbook of Nanomaterials in Analytical Chemistry

Figure 5.3 The schematic depiction of the preparation of magnetic Fe3O4/SiO2 nanoparticles. Source: Reproduced with permission from X. Wu, Y. Li, X. Zhu, C. He, Q. Wang, S. Liu, Dummy molecularly imprinted magnetic nanoparticles for dispersive solid phase extraction and determination of bisphenol A in water samples and orange juice, Talanta 162 (2017) 57
64.

Figure 5.4 The schematic depiction of the preparation of magnetic Co/SiO2 nanoparticles having ionic liquid layer toward Pb(II) ions. Source: Reproduced with permission from S. Hosseinzadegan, W. Nischkauer, K. Bica, A. Limbeck, FI-ICP-OES determination of Pb in drinking water after pre-concentration using magnetic nanoparticles coated with ionic liquid, Microchem. J. 146 (2019) 339
344.

magnetic Co/SiO2 nanoparticles having ionic liquid layer toward Pb(II) ions is shown in Fig. 5.4. In this study, the achieved detection limit value was 0.01 μg L21. In another interesting study conducted by Shahriman et al. [77], magnetic Fe3O4 nanoparticles coated with polyaniline-dicationic ionic liquid were prepared for the selective extraction of polycyclic aromatic hydrocarbons (PAHs) from soil, sludge, and environmental water samples. The achieved results confirmed that the prepared magnetic nanoparticles exhibited excellent extraction performance toward the target PAHs in environmental samples. The detection limit values varied in the range between 0.0008 and 0.2086 μg L21. Al-Harahsheh and colleagues reported the preparation of magnetic Fe3O4 nanoparticles functionalized with polyamine/amide for the efficient extraction of U(VI) ions from aqueous solutions [78]. In their study, the binding capacity of the prepared magnetic nanoparticles was obtained as 127.5 mg g21.

The use of magnetic nanoparticles in sample preparation devices and tools

85

5.4.2 Magnetic solid-phase extraction for food and beverage samples Magnetic nanoparticles were also successfully applied for the sample preparation step of the analysis of food and beverage samples. Some examples are briefly described in the following paragraphs. In a study carried out by Li and colleagues [79], magnetic Fe3O4 nanoparticles coated with polyvinyl alcohol layer were synthesized for the selective extraction of aminoglycoside antibiotics including streptomycin, dihydrostreptomycin, and kanamycin in honey samples. The prepared magnetic nanoparticles successfully extracted the target aminoglycoside antibiotics in a very short time (30 s). The detection limit values for streptomycin, dihydrostreptomycin, and kanamycin were found as 0.993, 0.913, and 1.23 μg kg21, respectively. In another interesting study [80], Zhao et al. prepared magnetic Fe3O4 nanoparticles grafted with alendronate sodium for the selective extraction of trans-resveratrol in peanut oils. The achieved results showed that the whole extraction process was accomplished in 10 min. The obtained recovery values varied in the range between 78.6% and 118.9%. The detection limit was calculated as 0.3 ng g21. Khodadadi and coworkers reported the design and development of magnetic Fe3O4@SiO2 nanoparticles functionalized with aptamer for the efficient extraction of aflatoxin M1 from milk samples [81]. The detection limit was found as 0.2 ng L21. Authors reported that this was the lowest achieved value that was reported in the literature up to now. In another important work conducted by Wang et al. [82], various estrogens including 17β-estradiol, estrone, and diethylstilbestrol were successfully extracted from pork samples by using magnetic Fe3O4@caprylic acid nanoparticles coated with cetyltrimethyl ammonium bromide. In their study, the obtained results showed that extraction equilibrium for the target estrogens was obtained in a very short time (2 min). The achieved detection limit values varied in the range from 0.021 to 0.033 ng mL21. Yang and coworkers designed and developed magnetic Fe3O4 nanoparticles coated with magnesium
aluminum-layered double hydroxides [83]. The prepared magnetic composite nanoparticles were successfully applied for the effective extraction of bisphenols including BPA, bisphenol-AF, tetrabromobisphenol-A, and 4-tertoctylphenol from various fruit juices including peach juice, apple juice, and orange juice. Fig. 5.5 shows the schematic demonstration of the extraction process for the target compounds in fruit juice samples using magnetic nanoparticles. In this study, the detection limit values for BPA, bisphenol-AF, tetrabromobisphenolA, and 4-tertoctylphenol were obtained as 0.54, 0.48, 0.37, and 0.63 μg L21, respectively. In another interesting study carried out by Zhao and colleagues [84], chlorogenic acid was successfully extracted from Honeysuckle tea samples by using MIP-based magnetic nanoparticles. In their study, magnetic Fe3O4 nanoparticles were first modified with ethanediamine and methyl acrylate to provide the high number of functional amino groups. Then, chlorogenic acid-selective MIP layer was synthesized on the surface of magnetic Fe3O4 nanoparticles using dopamine as the

86

Handbook of Nanomaterials in Analytical Chemistry

Figure 5.5 The schematic demonstration of the extraction process for the target compounds in fruit juice samples using magnetic nanoparticles. Source: Reproduced with permission from D. Yang, X. Li, D. Meng, M. Wang, Y. Yang, Supramolecular solvents combined with layered double hydroxide coated magnetic nanoparticles for extraction of bisphenols and 4-tertoctylphenol from fruit juices, Food. Chem. 237 (2017) 870
876.

functional monomer. The prepared MIP-based magnetic nanoparticles were successfully applied for the efficient extraction of chlorogenic acid from Honeysuckle tea samples. The detection limit and quantification limit values were achieved as 0.01 and 0.038 μg mL21, respectively. Guo et al. prepared magnetic Fe3O4@SiO2 nanoparticles modified with octadecyl (C18) functional groups for the extraction of phthalic acid esters from Chinese herbs [85]. In this study, the achieved detection limit was ,1.89 ng mL21. In another interesting work reported by Liang and coworkers [86], magnetic Fe3O4@SiO2/GO nanocomposites functionalized with metal-organic framework MIL101 (Cr) were successfully prepared and applied for the efficient extraction of various triazine herbicides including secbumeton, terbuthylazine, trietazine, atrazine, terbumeton, atraton, and prometon from rice samples. The obtained detection limit values for the target triazine herbicides were in the range between 0.010 and 0.080 μg kg21. Gonza´lez-Sa´lamo and colleagues reported the preparation of magnetic Fe3O4 nanoparticles having poly(dopamine) layer for the effective extraction of various mycotoxins including zearalenone, α-zearalanol, β-zearalanol, α-zearalenol, β-zearalenol, and zearalanone from yogurt and milk samples [87]. In their study, the achieved detection limit values for yogurt samples and milk samples were in the range from 0.29 to 4.54 μg kg21 and 0.21 to 4.77 μg L21.

5.4.3 Magnetic solid-phase extraction for biological samples MSPE for biological samples (i.e., blood plasma, urine, etc.) is another crucial application area of magnetic nanoparticles. In a study carried out by Heidari and

The use of magnetic nanoparticles in sample preparation devices and tools

87

Figure 5.6 The schematic depiction of the extraction process for the target drugs from biological samples using magnetic nanocomposites. Source: Reproduced with permission from A.A. Asgharinezhad, H. Ebrahimzadeh, F. Mirbabaei, N. Mollazadeh, N. Shekari, Dispersive micro-solid-phase extraction of benzodiazepines from biological fluids based on polyaniline/magnetic nanoparticles composite, Anal. Chim. Acta 844 (2014) 80
89.

Limouei-Khosrowshahi [88], magnetic Fe3O4 nanoparticles modified with carbon were prepared for the extraction of various pharmaceutical compounds including carvedilol, losartan, and amlodipine besylate from plasma samples. In this study, the detection limit values varied in the range between 0.09 and 0.69 ng mL21. In another important work [89], Asgharinezhad et al. developed magnetic nanocomposite composed of Fe3O4 nanoparticles and polyaniline. The developed magnetic nanocomposite was successfully applied for the efficient extraction of benzodiazepine drugs including nitrazepam and lorazepam from human plasma and urine samples. The schematic depiction of the extraction process for the target drugs from biological samples using magnetic nanocomposites is shown in Fig. 5.6. The detection limit values for nitrazepam and lorazepam were obtained in the range from 0.5 to 1.8 μg L21 and 0.2 to 2.0 μg L21, respectively. Feng and colleagues reported the design and preparation of Fe3O4 nanoparticlemodified multi-walled carbon nanotubes (MWCNTs) [90]. The prepared MWCNTbased nanocomposites were successfully used for the efficient extraction of brucine (a neurotoxic alkaloid existing in the Nux-vomica tree) from human urine samples. In their study, the detection limit and quantification limit values were achieved as 6 and 21 ng mL21, respectively. In another interesting study conducted by Chen and coworkers [91], magnetic Fe3O4 nanoparticles having a layer composed of 1,3,5-triformylbenzene(Tb) and benzidine (Bd) (Fe3O4@TbBd) were prepared and successfully applied for the

88

Handbook of Nanomaterials in Analytical Chemistry

Figure 5.7 The schematic demonstration of the preparation of magnetic Fe3O4@TbBd nanocomposite (A) and extraction process for the target estrogens (B). Source: Reproduced with permission from L. Chen, M. Zhang, F. Fu, J. Li, Z. Lin, Facile synthesis of magnetic covalent organic framework nanobeads and application to magnetic solid-phase extraction of trace estrogens from human urine, J. Chromatogr. A 1567 (2018) 136
146.

selective extraction of seven estrogens from human urine samples. The schematic demonstration of the preparation of magnetic Fe3O4@TbBd nanocomposite and extraction process for the target estrogens is shown in Fig. 5.7. In this study, the achieved detection limit values varied in the range from 0.2 to 7.7 ng L21. Mirzapour et al. reported the preparation of organic dendrimer-modified magnetic Fe3O4 nanoparticles for the efficient extraction of rosuvastatin from human urine, blood plasma, and tablet samples [92]. For this purpose, first, magnetic Fe3O4 nanoparticles were synthesized by using FeCl2 and FeCl3. Then the surface of the synthesized magnetic Fe3O4 nanoparticles was modified with organic dendrimers containing ethylene diamine and methyl methacrylate. The prepared organic dendrimer-modified magnetic Fe3O4 nanoparticles were successfully used for the extraction of the target pharmaceutical compound rosuvastatin from human urine, blood plasma, and tablet samples. In this study, the highest extraction capacity of the prepared organic dendrimer-modified magnetic Fe3O4 nanoparticles was achieved as 61 mg g21. In another study reported by Ji and colleagues [93], magnetic Fe3O4 nanoparticles having MIP layer were successfully prepared and applied for the selective extraction of 9-hydroxyrisperidone and risperidone from human urine samples. The obtained detection limit values for 9-hydroxyrisperidone and risperidone were 0.24 and 0.21 ng mL21, respectively. Azodi-Deilami and coworkers prepared magnetic Fe3O4 nanoparticles coated with molecularly imprinted polymeric shell for the selective extraction of paracetamol from human plasma samples [94]. In their study, the detection limit and

The use of magnetic nanoparticles in sample preparation devices and tools

89

quantification limit values for the target pharmaceutical compound paracetamol in human plasma were achieved as 0.17 and 0.4 μg L21, respectively. In another interesting study [95], Jiang et al. reported the development of magnetic Fe3O4@SiO2 nanoparticles modified with octadecyl (C18) functional groups for the efficient extraction of aromatic amines including 1-aminonaphthalene, 4-aminobiphenyl, 4,4ʹ-diaminodiphenylmethane and 4-aminophenylthioether from human urine samples. The detection limit values for 1-aminonaphthalene, 4-aminobiphenyl, 4,4ʹ-diaminodiphenylmethane, and 4-aminophenylthioether were obtained as 1.3, 0.88, 1.1, and 1.1 ng mL21, respectively. Zhang and colleagues prepared polydopamine-coated magnetic Fe3O4 nanoparticles modified with MWCNTs for the extraction of antiepileptic drugs including phenytoin, oxcarbazepine, and carbamazepine from human urine, plasma, and cerebrospinal fluid samples [96]. In their study, the achieved detection limit values for the target drug compounds were in the range between 0.4 and 3.1 ng mL21.

5.5

Conclusion and future trends

The growing number of research in which magnetic nanoparticles were successfully applied used MSPE processes, confirming that these nanomaterials with unique features are promising for the selective extraction of target compound/s from complex matrices (i.e., environmental, biological, food, and beverage samples). The reported examples briefly demonstrated in this chapter highlight the latest progresses in sample preparation applications by using magnetic nanoparticles over the past years. Magnetic nanoparticles exhibit great properties (i.e., small size, high surface area, active surface that can easily be modified, low toxicity, and superparamagnetism). These great properties of magnetic nanoparticles make them unique candidates for the design and preparation of new functional nanomaterials for the SPE processes. Magnetic nanoparticles are directly dispersed in the sample solutions for quick extraction of the target compound/s, as they can be readily recovered by a magnet, which overcomes drawbacks of the conventional extraction materials such as time consumption and large volume of samples. Efficient extraction of the target compound/s by using magnetic nanoparticles can also eliminate the matrix effects usually observed in the conventional SPE processes. In addition, high extraction capacity provides successful applications of the magnetic nanoparticles for efficient extraction of trace analytes from complex samples. The automation possibilites of the MSPE process also provide highthroughput analysis by applying this approach. Moreover, a promising and crucial goal in this area is the design and development of new strategies and techniques for the preparation and functionalization of the magnetic nanoparticles and increasing their chemical and physical stability, selectivity toward the target compound/s in complex samples and lifespan.

90

Handbook of Nanomaterials in Analytical Chemistry

References [1] A. Wasik, A. Kot-Wasik, J. Namiesnik, New trends in sample preparation techniques for the analysis of the residues of pharmaceuticals in environmental samples, Curr. Anal. Chem. 12 (2016) 280
302. [2] C. Ribeiro, A.R. Ribeiro, A.S. Maia, V.M.F. Goncalves, M.E. Tiritan, New trends in sample preparation techniques for environmental analysis, Crit. Rev. Anal. Chem. 44 (2014) 142
185. [3] C. Calderilla, F. Maya, L.O. Leal, V. Cerda, Recent advances in flow-based automated solid-phase extraction, Trends Anal. Chem. 108 (2018) 370
380. [4] J. Płotka-Wasylka, N. Szczepanska, M. de la Guardia, J. Namiesnik, Modern trends in solid phase extraction: new sorbent media, Trends Anal. Chem. 77 (2016) 23
43. [5] J. Xu, J. Zheng, J. Tian, F. Zhu, F. Zeng, C. Su, et al., New materials in solid-phase microextraction, Trends Anal. Chem. 47 (2013) 68
83. [6] B. Buszewski, M. Szultka, Past, present, and future of solid phase extraction: a review, Crit. Rev. Anal. Chem. 42 (2012) 198
213. [7] A. Azzouz, S.K. Kailasa, S.S. Lee, A.J. Rascon, E. Ballesteros, M. Zhang, et al., Review of nanomaterials as sorbents in solid-phase extraction for environmental samples, Trends Anal. Chem. 108 (2018) 347
369. [8] N. Reyes-Garce´s, E. Gionfriddo, G.A. Go´mez-Rı´os, Md.N. Alam, E. Boyacı, B. Bojko, et al., Advances in solid phase microextraction and perspective on future directions, Anal. Chem. 90 (2018) 302
360. [9] T. Khezeli, A. Daneshfar, Development of dispersive micro-solid phase extraction based on micro and nano sorbents, Trends Anal. Chem. 89 (2017) 99
118. [10] M. Wierucka, M. Biziuk, Application of magnetic nanoparticles for magnetic solidphase extraction in preparing biological, environmental and food samples, Trends Anal. Chem. 59 (2014) 50
58. [11] M. Maier, H. Fritz, M. Gerster, J. Schewitz, E. Bayer, Quantitation of phosphorothioate oligonucleotides in human blood plasma using a nanoparticle-based method for solidphase extraction, Anal. Chem. 70 (1998) 2197
2204. [12] H.H. Yang, S.Q. Zhang, X.L. Chen, Z.X. Zhuang, J.G. Xu, X.R. Wang, Magnetitecontaining spherical silica nanoparticles for biocatalysis and bioseparations, Anal. Chem. 76 (5) (2004) 1316
1321. [13] P.R. Sudhir, H.F. Wu, Z.C. Zhou, Identification of peptides using gold nanoparticleassisted single-drop microextraction coupled with AP-MALDI mass spectrometry, Anal. Chem. 77 (2005) 7380
7385. [14] B.N.Y. Vanderpuije, G. Han, V.M. Rotello, R.W. Vachet, Mixed monolayer-protected gold nanoclusters as selective peptide extraction agents for MALDI-MS analysis, Anal. Chem. 78 (2006) 5491
5496. [15] S.Y. Chang, N.Y. Zheng, C.S. Chen, C.D. Chen, Y.Y. Chen, C.R. Wang, Analysis of peptides and proteins affinity-bound to iron oxide nanoparticles by MALDI MS, J. Am. Soc. Mass. Spectrom. 18 (2007) 910
918. [16] P.C. Lin, M.C. Tseng, A.K. Su, Y.J. Chen, C.C. Lin, Functionalized magnetic nanoparticles for small-molecule isolation, identification, and quantification, Anal. Chem. 79 (2007) 3401
3408. [17] C.M. Hussain, Magnetic nanomaterials for environmental analysis, in: C.M. Hussain, B. Kharisov (Eds.), Advanced Environmental Analysis-Application of Nanomaterials, The Royal Society of Chemistry, 2017.

The use of magnetic nanoparticles in sample preparation devices and tools

91

[18] R. Kec¸ili, C.M. Hussain, Recent progress of imprinted nanomaterials in analytical chemistry, Int. J. Anal. Chem. (2018). Article ID8503853. [19] S. Bu¨yu¨ktiryaki, Y. Su¨mbelli, R. Kec¸ili, C.M. Hussain, Lab-On-Chip Platforms for Environmental Analysis, in: P. Worsfold, C. Poole, A. Townshend, M. Miro´ (Eds.), Encyclopedia of Analytical Science, third ed., Academic Press, 2019, pp. 267
273. [20] R. Kec¸ili, S. Bu¨yu¨ktiryaki, C.M. Hussain, Advancement in bioanalytical science through nanotechnology: past, present and future, TrAC Trends Anal. Chem. 110 (2019) 259
276. [21] S. Chikazumi, S. Taketomi, M. Ukita, M. Mizukami, H. Miyajima, M. Setogawa, et al., Physics of magnetic fluids, J. Magn. Magn. Mater. 65 (1987) 245
251. [22] A.H. Lu, W. Schmidt, N. Matoussevitch, H. Bonnemann, B. Spliethoff, B. Tesche, et al., Nanoengineering of a magnetically separable hydrogenation catalyst, Angew. Chem. Int. Ed. Engl. 43 (2004) 4303
4306. [23] Z. Li, L. Wei, M.Y. Gao, H. Lei, One-pot reaction to synthesize biocompatible magnetite nanoparticles, Adv. Mater. 17 (2005) 1001
1005. [24] A. Farrukh, A. Akram, A. Ghaffar, S. Hanif, A. Hamid, H. Duran, et al., Design of polymer-brush-grafted magnetic nanoparticles for highly efficient water remediation, ACS Appl. Mater. Interfaces 5 (2013) 3784
3793. [25] P.C. Lin, C.C. Yu, H.T. Wu, Y.W. Lu, C.L. Han, A.K. Su, et al., A chemically functionalized magnetic nanoplatform for rapid and specific biomolecular recognition and separation, Biomacromolecules 14 (2013) 160
168. [26] A.H. Lu, E.L. Salabas, F. Schuth, Magnetic nanoparticles: synthesis, protection, functionalization, and application, Angew Chem. Int. Ed. 46 (2007) 1222
1244. [27] L.Z. Gao, J.M. Wu, S. Lyle, K. Zehr, L.L. Cao, D. Gao, Magnetite nanoparticle-linked immunosorbent assay, J. Phys. Chem. C 112 (2008) 17357
17361. [28] S. Behrens, Preparation of functional magnetic nanocomposites and hybridmaterials: recent progress and future directions, Nanoscale 3 (2011) 877
892. [29] A. Ahniyaz, Y. Sakamoto, L. Bergstro¨m, Magnetic field-induced assembly oforiented superlattices from maghemite nanocubes, Proc. Natl. Acad. Sci. U.S.A. 104 (2007) 17570
17574. [30] F.X. Redl, K.S. Cho, C.B. Murray, S. O’Brien, Three-dimensional binary super-lattices of magnetic nanocrystals and semiconductor quantum dots, Nature 423 (2003) 968
971. [31] T.O. Ely, C. Amiens, B. Chaudret, E. Snoeck, M. Verelst, M. Respaud, et al., Synthesis of nickel nanoparticles. Influence of aggregation induced by modi-fication of poly (vinylpyrrolidone) chain length on their magnetic properties, Chem. Mater. 11 (1999) 526
529. [32] J. Osuna, D. de Caro, C. Amiens, B. Chaudret, E. Snoeck, M. Respaud, et al., Synthesis, characterization, and magnetic properties of cobaltnanoparticles from an organometallic precursor, J. Phys. Chem. C 100 (1996) 14571
14574. [33] J.H. Lee, Y.M. Huh, Y. Jun, J. Seo, J. Jang, H.T. Song, et al., Artificially engineered magnetic nanoparticles for ultra-sensitive molecular imaging, Nat. Med. 13 (2006) 95
99. [34] F.Q. Hu, L. Wei, Z. Zhou, Y.L. Ran, Z. Li, M.Y. Gao, Preparation of biocompatiblemagnetite nanocrystals for in vivo magnetic resonance detection of cancer, Adv. Mater. 18 (2006) 2553
2556. [35] L.H. Reddy, J.L. Arias, J. Nicolas, P. Couvreur, Magnetic nanoparticles: designand characterization, toxicity and biocompatibility, pharmaceutical and biomedical applications, Chem. Rev. 112 (2012) 5818
5878.

92

Handbook of Nanomaterials in Analytical Chemistry

[36] R. Massart, Preparation of aqueous magnetic liquids in alkaline and acidicmedia, IEEE. Trans. Magn. 17 (1981) 1247
1248. [37] J. Liu, S.Z. Qiao, Q.H. Hu, G.Q. Lu, Magnetic nanocomposites with mesoporousstructures: synthesis and applications, Small 7 (2011) 425
443. [38] R. Massart, V. Cabuil, Effect of some parameters on the formation of colloidalmagnetite in alkaline medium: yield and particle size control, J. Chim. Phys. PCB 84 (1987) 967
973. [39] H. Itoh, T. Sugimoto, Systematic control of size, shape, structure, and magnetic properties of uniform magnetite and maghemite particles, J. Colloid Interf. Sci. 265 (2003) 283
295. [40] C. Cannas, D. Gatteschi, A. Musinu, G. Piccaluga, C. Sangregorio, Structural and magnetic properties of Fe2O3 nanoparticles dispersed over a silica matrix, J. Phys. Chem. B 102 (1998) 7721
7726. [41] F. Chen, Q. Gao, G. Hong, J. Ni, Synthesis and characterization of magnetite dodecahedron nanostructure by hydrothermal method, J. Magn. Magn. Mater. 320 (2008) 1775
1780. [42] A. Bee, R. Massart, S. Neveu, Synthesis of very fine maghemite particles, J. Magn. Magn. Mater. 149 (1995) 6
9. [43] C. Petit, A. Taleb, M.P. Pileni, Cobalt nanosized particles organized in a 2D superlattice: synthesis, characterization, and magnetic properties, J. Phys. Chem. B 103 (1999) 1805
1810. [44] D.H. Chen, S.H. Wu, Synthesis of nickel nanoparticles in water-in-oilmicroemulsion, Chem. Mater. 12 (2000) 1354
1360. [45] G. Salazar-Alvarez, M. Muhammed, A.A. Zagorodni, Novel flow injection syn-thesis of iron oxide nanoparticles with narrow size distribution, Chem. Eng. Sci. 61 (2006) 4625
4633. [46] R. Strobel, S.E. Pratsinis, Direct synthesis of maghemite, magnetite and wustitenanoparticles by flame spray pyrolysis, Adv. Powder Technol. 20 (2009) 190
194. [47] S. Veintemillas-Verdaguer, Y. Leconte, R. Costo, O. Bomati-Miguel, B. Bouchet-Fabre, M.P. Morales, et al., Continuous production of inorganic magnetic nanocomposites for biomedicalapplications by laser pyrolysis, J. Magn. Magn. Mater. 311 (2007) 120
124. [48] I. Liska, Fifty years of solid-phase extraction in water analysis
historical development and overview, J. Chromatogr. A 885 (2000) 3
16. [49] B.Y. Spivakov, G.I. Malofeeva, O.M. Petrukhin, Solid-phase extraction on alkylbonded silica gels in inorganic analysis, Anal. Sci. 22 (2006) 503
519. [50] J.A. Rodrı´guez, K.A. Escamilla-Lara, A. Guevara-Lara, J.M. Miranda, M.E. Pa´ezHerna´ndez, Application of an activated carbon-based support for magnetic solid phase extraction followed by spectrophotometric determination of tartrazine in commercial beverages, Int. J. Anal. Chem. 2015 (2015) 1
8. [51] M.G. Valde´s, A.I. Pe´rez-Cordoves, M.E. Dı´az-Garcı´a, Zeolites and zeolite-based materials in analytical chemistry, TrAC Trends Anal. Chem. 25 (2006) 24
30. ¨ zcan, A. Erso¨z, D. Hu¨r, A. Denizli, R. Say, Superparamagnetic [52] R. Kec¸ili, A. Atilir O nanotraps containing MIP based mimic lipase for biotransformations uses, J. Nanopart. Res. 13 (2011) 2073
2079. [53] S. Bucak, D.A. Jones, P.E. Laibinis, T.A. Hatton, Protein separations using colloidal magnetic nanoparticles, Biotechnol. Progr. 19 (2003) 477
484. [54] S. Bu¨yu¨ktiryaki, L. Uzun, A. Denizli, R. Say, A. Erso¨z, Simultaneous depletion of albumin and immunoglobulin G by using twin affinity magnetic nanotraps, Sep. Sci. Technol. 51 (2016) 2080
2089.

The use of magnetic nanoparticles in sample preparation devices and tools

93

[55] G. Prabha, V. Raj, Preparation and characterization of polymer nanocomposites coated magnetic nanoparticles for drug delivery applications, J. Magn. Magn. Mater. 408 (2016) 26
34. [56] M. Safarikova, I. Safarik, Magnetic separations in natural sciences and biotechnology, Chem. Listy 89 (1995) 280
287. [57] S.A. Haeri, S. Abbasi, New strategy for the biosorption of atrazine after magnetic solid-phase extraction from water followed by high-performance liquid chromatography analysis, J. Sep. Sci. 39 (2016) 2839
2845. [58] Y. Dai, L. Niu, J. Zou, T. Chen, H. Liu, Y. Zhou, Preparation of core-shell magnetic Fe3O4@SiO2-dithiocarbamate nanoparticle and its application for the Ni21, Cu21 removal, Chin. Chem. Lett. 29 (2018) 887
891. [59] T. Sun, Z. Zhao, Z. Liang, J. Liu, W. Shi, F. Cui, Efficient removal of arsenite through photocatalytic oxidation and adsorption by ZrO2-Fe3O4 magnetic nanoparticles, Appl. Surf. Sci. 416 (2017) 656
665. [60] S.F. Soares, T. Fernandes, M. Sacramento, T. Trindade, A.L. Daniel-da-Silva, Magnetic quaternary chitosan hybrid nanoparticles for the efficient uptake of diclofenac from water, Carbohydr. Polym. 203 (2019) 35
44. [61] Y.-Z. Ma, D.-F. Zheng, Z.-Y. Mo, R.-J. Dong, X.-Q. Qiu, Magnetic lignin-based carbon nanoparticles and the adsorption for removal of methyl orange, Colloids Surf. A 559 (2018) 226
234. [62] F. Golmohammadi, M. Hazrati, M. Safari, Removal of reactive yellow 15 from water sample using a magnetite nanoparticles coated with covalently immobilized dimethyl octadecyl [3-(trimethoxysilylpropyl)] ammonium chloride ionic liquid, Microchem. J. 144 (2019) 64
72. [63] M. Pascale, A. De Girolamo, A. Visconti, N. Magan, I. Chianella, E.V. Piletska, et al., Use of itaconic acid-based polymers for solid-phase extraction of deoxynivalenol and application to pasta analysis, Anal. Chim. Acta 609 (2008) 131
138. [64] F. Puoci, M. Curcio, G. Cirillo, F. Iemma, U. Spizzirri, N. Picci, Molecularly imprinted solid-phase extraction for cholesterol determination in cheese products, Food Chem. 106 (2008) 836
842. [65] A. Beltran, R. Marce´, P. Cormack, F. Borrull, Synthesis by precipitation polymerisation of molecularly imprinted polymer microspheres for the selective extraction of carbamazepine and oxcarbazepine from human urine, J. Chromatogr. A 1216 (2009) 2248
2253. [66] L. Andersson, M. Abdel-Rehim, L. Nicklasson, L. Schweitz, S. Nilsson, Towards molecular-imprint based SPE of local anaesthetics, Chromatographia 55 (2002) S65
S69. [67] Y.H. Li, T. Yang, X.L. Qi, Y.W. Qiao, A.P. Deng, Development of a group selective molecularly imprinted polymers based solid phase extraction of malachite green from fish water and fish feed samples, Anal. Chim. Acta 624 (2008) 317
325. [68] V. Pichon, M. Bouzige, C. Mie`ge, M.-C. Hennion, Immunosorbents: natural molecular recognition materials for sample preparation of complex environmental matrices, TrAC Trends Anal. Chem. 18 (1999) 219
235. [69] J. Wackerlig, P.A. Lieberzeit, Molecularly imprinted polymer nanoparticles in chemical sensing - synthesis, characterisation and application, Sens. Actuators B Chem. 207 (2015) 144
157. [70] W. Jiang, X. Jin, X. Yu, W. Wu, L. Xu, F. Fu, Ion-imprinted magnetic nanoparticles for specific separation and concentration of ultra-trace methyl mercury from aqueous sample, J. Chromatogr. A 1496 (2017) 167
173.

94

Handbook of Nanomaterials in Analytical Chemistry

[71] Z.H. Hu, Y.F. Wang, A.M. Omer, X.K. Ouyang, Fabrication of ofloxacin imprinted polymer on the surface of magnetic carboxylated cellulose nanocrystals for highly selective adsorption of fluoroquinolones from water, Int. J. Biol. Macromol. 107 (2018) 453
462. ´ lvarez, A. Martı´n-Esteban, Molecularly imprinted core[72] M.J. Patin˜o-Ropero, M. Dı´az-A shell magnetic nanoparticles for selective extraction of triazines in soils, J. Mol. Recognit. 30 (2017) e2593. [73] X. Qi, S. Gao, G. Ding, A.-N. Tang, Synthesis of surface Cr (VI)-imprinted magnetic nanoparticles for selective dispersive solid-phase extraction and determination of Cr (VI) in water samples, Talanta 162 (2017) 345
353. [74] A. Barati, E. Kazemi, S. Dadfarnia, A.M.H. Shabani, Synthesis/characterization of molecular imprinted polymer based on magnetic chitosan/graphene oxide for selective separation/preconcentration of fluoxetine from environmental and biological samples, J. Ind. Eng. Chem. 46 (2017) 212
221. [75] X. Wu, Y. Li, X. Zhu, C. He, Q. Wang, S. Liu, Dummy molecularly imprinted magnetic nanoparticles for dispersive solidphase extraction and determination of bisphenol A in water samples and orange juice, Talanta 162 (2017) 57
64. [76] S. Hosseinzadegan, W. Nischkauer, K. Bica, A. Limbeck, FI-ICP-OES determination of Pb in drinking water after pre-concentration using magnetic nanoparticles coated with ionic liquid, Microchem. J. 146 (2019) 339
344. [77] M.S. Shahriman, M.R. Ramachandran, N.N.M. Zain, S. Mohamad, N.S.A. Manan, S. M. Yaman, Polyaniline-dicationic ionic liquid coated with magnetic nanoparticles composite for magnetic solid phase extraction of polycyclic aromatic hydrocarbons in environmental samples, Talanta 178 (2018) 211
221. [78] M. Al-Harahsheh, M. AlJarrah, M. Mayyas, M. Alrebaki, High-stability polyamine/ amide-functionalized magnetic nanoparticles for enhanced extraction of uranium from aqueous solutions, J. Taiwan Inst. Chem. E 86 (2018) 148
157. [79] D. Li, T. Li, L. Wang, S. Ji, A polyvinyl alcohol-coated core-shell magnetic nanoparticle for the extraction of aminoglycoside antibiotics residues from honey samples, J. Chromatogr. A 1581
1582 (2018) 1
7. [80] Q. Zhao, D.-Q. Cheng, M. Tao, W.-J. Ning, Y.-J. Yang, K.-Y. Meng, et al., Rapid magnetic solid-phase extraction based on alendronate sodium grafted mesoporous magnetic nanoparticle for the determination of trans-resveratrol in peanut oils, Food Chem. 279 (2019) 187
193. [81] M. Khodadadi, A. Malekpour, M.A. Mehrgardi, Aptamer functionalized magnetic nanoparticles for effectiveextraction of ultratrace amounts of aflatoxin M1 prior itsdetermination by HPLC, J. Chromatogr. A 1564 (2018) 85
93. [82] J. Wang, Z. Chen, Z. Li, Y. Yang, Magnetic nanoparticles based dispersive microsolid-phase extraction as a novel technique for the determination of estrogens in pork samples, Food Chem. 204 (2016) 135
140. [83] D. Yang, X. Li, D. Meng, M. Wang, Y. Yang, Supramolecular solvents combined with layered double hydroxidecoated magnetic nanoparticles for extraction of bisphenols and 4-tertoctylphenol from fruit juices, Food Chem. 237 (2017) 870
876. [84] Y. Zhao, Y. Tang, J. He, Y. Xu, R. Gao, J. Zhang, et al., Surface imprinted polymers based on amino-hyperbranched magnetic nanoparticles for selective extraction and detection of chlorogenic acid in Honeysuckle tea, Talanta 181 (2018) 271
277. [85] B. Guo, S. Ji, F. Zhang, B. Yang, J. Gu, X. Liang, Preparation of C18-functionalized Fe3O4@SiO2 core
shell magnetic nanoparticles for extraction and determination of

The use of magnetic nanoparticles in sample preparation devices and tools

[86]

[87]

[88]

[89]

[90]

[91]

[92]

[93]

[94]

[95]

[96]

95

phthalic acid esters in Chinese herb preparations, J. Pharm. Biomed. Anal. 100 (2014) 365
368. L. Liang, X. Wang, Y. Sun, P. Ma, X. Li, H. Piao, et al., Magnetic solid-phase extraction of triazine herbicides from rice using metal-organic framework MIL-101(Cr) functionalized magnetic particles, Talanta 179 (2018) 512
519. ´ ngel Rodrı´guezJ. Gonza´lez-Sa´lamo, B. Socas-Rodrı´guez, J. Herna´ndez-Borges, M. A Delgado, Core-shell poly(dopamine) magnetic nanoparticles for the extraction of estrogenic mycotoxins from milk and yogurt prior to LC
MS analysis, Food Chem. 215 (2017) 362
368. H. Heidari, B. Limouei-Khosrowshahi, Magnetic solid phase extraction with carboncoated Fe3O4 nanoparticles coupled to HPLC-UV for the simultaneous determination of losartan, carvedilol, and amlodipine besylate in plasma samples, J. Chromatogr. B 1114
1115 (2019) 24
30. A.A. Asgharinezhad, H. Ebrahimzadeh, F. Mirbabaei, N. Mollazadeh, N. Shekari, Dispersive micro-solid-phase extraction of benzodiazepines from biological fluids based on polyaniline/magnetic nanoparticles composite, Anal. Chim. Acta 844 (2014) 80
89. Z. Feng, R. Yang, B. Du, Fast SPE and HPLC
DAD determination of brucine in human urine using multi-walled carbon nanotubes modified with magnetic nanoparticles, J. Anal. Chem. 72 (8) (2017) 862
869. L. Chen, M. Zhang, F. Fu, J. Li, Z. Lin, Facile synthesis of magnetic covalent organic framework nanobeadsand application to magnetic solid-phase extraction of trace estrogensfrom human urine, J. Chromatogr. A 1567 (2018) 136
146. H. Mirzapour, H.A. Panahi, E. Moniri, A. Feizbakhsh, Magnetic nanoparticles modified with organic dendrimers containing methyl methacrylate and ethylene diamine for the microextraction of rosuvastatin, Microchim. Acta 185 (2018) 440. W.-H. Ji, Y.-S. Guo, X. Wang, D.-S. Guo, A water-compatible magnetic molecularly imprinted polymer for the selective extraction of risperidone and 9-hydroxyrisperidone from human urine, Talanta 181 (2018) 392
400. S. Azodi-Deilami, A.H. Najafabadi, E. Asadi, M. Abdouss, D. Kordestani, Magnetic molecularly imprinted polymer nanoparticles for the solid-phase extraction of paracetamol from plasma samples, followed its determination by HPLC, Microchim. Acta 181 (2014) 1823
1832. C. Jiang, Y. Sun, X. Yu, Y. Gao, L. Zhang, Y. Wang, et al., Application of C18functional magnetic nanoparticles for extraction of aromatic amines from human urine, J. Chromatogr. B 947
948 (2014) 49
56. R. Zhang, S. Wang, Y. Yang, Y. Deng, D. Li, P. Su, et al., Modification of polydopamine-coated Fe3O4 nanoparticles with multi-walled carbon nanotubes for magnetic-μ-dispersive solid-phase extraction of antiepileptic drugs in biological matrices, Anal. Bioanal. Chem. 410 (2018) 3779
3788.

Separation techniques with nanomaterials

6

Prasad Minakshi1, Mayukh Ghosh2, Basanti Brar1, Koushlesh Ranjan3, Harshad Sudhir Patki4 and Rajesh Kumar5 1 Department of Animal Biotechnology, LLR University of Veterinary and Animal Sciences, Hisar, India, 2Department of Veterinary Physiology and Biochemistry, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, India, 3Department of Veterinary Physiology and Biochemistry, COVAS, SVP University of Agriculture and Technology, Meerut, India, 4Department of Veterinary Anatomy and Histology, COVAS, KVASU, Pookode, India, 5Department of Veterinary Physiology, COVAS, KVASU, Pookode, India

6.1

Introduction

Qualitative and quantitative analysis of the constituents of a complex mixture never suffice enough to the complete elucidation of processes involving each of the component or their property, nor it facilitates further complete downstream exploitation of individual elements unless separated from the mother soup. Thus isolation or separation of the targeted molecule or a group of molecules from the complex mixture remains at the center of focus in analytical chemistry. Chromatographic methods and electrophoretic techniques are the key vertices on which state-of-the-art separation techniques have prospered incessantly. The entire separation process comprises of preconcentration or sample enrichment, proper separation, followed by derivatization and detection steps. In this analytical approach, maintenance of concentration economy of the target analytes throughout the entire process along with maximum signal generation of the specific analytes is of paramount importance. The challenges are further concentrated with the advent of “Omics era” which necessarily deals with minuscule sample volume and have a penetration up to the minute of single cell or beyond. Supreme sensitivity and specificity are not only of biological relevance but also the necessity of industrial applications, such as fuel technology, catalyst, sewage treatment, petroleum extraction, desalting sea water, obtaining trace and economical compound more effectively, or removing pollutant from air. Ample versatility of the analytical platforms is prerequisite to be compatible with such wide array of analytes in the form of gas, solid, liquid, or their combinations; simultaneously, it must be intelligent enough to accommodate the varied physicochemical properties of metal, organic, and inorganic compounds or molecules of biological significance, such as proteins, peptides, lipids, nucleotides, nucleic acids, and their glycoconjugates with different ionic and stoichiometric properties. Several chromatographic variants, such as gas chromatography (GC), Handbook of Nanomaterials in Analytical Chemistry. DOI: https://doi.org/10.1016/B978-0-12-816699-4.00006-2 Copyright © 2020 Elsevier Inc. All rights reserved.

100

Handbook of Nanomaterials in Analytical Chemistry

different forms of liquid chromatography (LC), reverse-phase LC (RPLC), and high-performance LC (HPLC)/ultra-HPLC, and various capillary electrophoretic methods are being most commonly employed as separation techniques along with the advanced microchip or microfluidics-based platforms for handling of microliters to industrial scale amount of samples. Continuous pursuit for advanced methods and improved separation media is going on to increase the throughput maintaining the natural integrity of the analytes, reproducibility, sensitivity, cost-effectiveness along with ease of operation and maintenance. In spite of considerable developments in every aspect of separation methodologies, an ideal platform with all the amenities is far from the reach, but state-of-the-art separation techniques have tried to accommodate as much as possible accounting every opportunity to minimize the inputs including the analysis of nanoliter quantity of sample with unprecedented sensitivity and nanomaterials (NMs) have found their niche during this process due to their unique physicochemical properties. NMs are atomic or molecular compounds in nanoscale typically in size of approximately 1 100 nm; these differ considerably from their bulk material with astonishing properties that has germinated the field of nanoscience or nanotechnology. It is the science of manipulating the existing NMs or building a new one in nanoscale. Nanotechnology is an emerging field of utility in nearly every arena of material science which includes, but not limited to, chemical science, analysis of biological phenomenon, development of different drugs and delivery systems, imaging and sensing techniques, diagnostics and vaccine developments, etc. Several methods, such as photolithography, arc discharge evaporation, micromachining, colloidal methods, sol gel processing, and hydro-thermal synthesis, generate NMs by either top-down or bottom-up approach which differ in their properties and shape from their bulk materials, and these properties, such as high surface-to-volume ratio, selectivity in molecular interactions, unique light scattering, and ample surface functionalities, are usually being exploited for various applications including separation methodologies [1,2]. The ease of generation, improved mass transfer, generation of differential electrophoretic mobility from electroosmotic flow (EOF) in capillary electrophoresis, enhancing column efficiency in chromatographic methods by increasing height equivalent to a theoretical plate (HETP), increase in specificity by molecular interactions with surface groups, and high adsorption capacity are the major factors which have rendered NMs a method of choice for the improvement in almost every existing separation techniques. Particularly, NMs are indispensable for the development of micro total analysis system or lab-on-a-chip analytical platform due to the size convenience along with the other beneficial properties. Despite unequivocal utility of NMs in every separation technique, sample preconcentration or enrichment is undoubtedly the widest application of NMs employing their enormous adsorption capacity. The present chapter deals with various nanoparticles (NPs) commonly employed in separation techniques, their properties perfectly fitting into the demands of separation methodologies, followed by multifaceted applications along with the future prospects and discussions.

Separation techniques with nanomaterials

6.2

101

Nanomaterials in separation techniques

Nanotechnology has prospered rapidly in the current era with targeted innovations finding solutions to age-old obstacles in diverse scientific arena and nano-interventions; in separation, science is not an exception. According to Eric Drexler, the word “nanotechnology” should only be used to describe atomically precise functional machine systems developed on the scale of the nanometer. These nano-sized materials termed NMs and/or NPs produced by the already mentioned methods or techniques, such as solvent evaporation, nano-precipitation, emulsification, diffusion, salting out, dialysis, supercritical fluid technology, polymerization in emulsion, interfacial polymerization, controlled/living radical polymerization, and ionic gelation, have the potential to intervene in every steps of separation techniques (preconcentration or sample enrichment, proper separation, and derivatization and detection process) for the enhancement of separation efficiency, specificity, sensitivity, and throughput due to their inherent unique optical, electrical, and magnetic properties; efficient heat conductivity; surface functionalities, better strength and durability; shape selectivity; and most importantly their high surface-to-volume ratio [2,3]. Theoretically infinite numbers and types of NMs can be generated from their precursors; however, only some of them have found applicability in separation science and the current discussion has been only restricted to the most popular ones. In general, carbon-based NMs and its allotropes, silica, metal and metal oxide NPs, metal organic frameworks (MOFs), and polymeric NMs are the most commonly applied NMs in recent separation platforms. Classification on the basis of dimension application can categorize these NMs into multiple classes, such as zero dimensional (0D) (NPs as such), where all three dimensions are in nanoscale range, one-dimensional (1D) nanostructures (e.g., nanotubes, nano-rods) where only two dimensions of the NM are in nanoscale range, two-dimensional (2D) nanostructures where only one dimension of the NM is in nanoscale range like in sheet (nanocoating, nano-layers) and 3D-nanostructures where all the three dimensions of the NMs are outside nanoscale range (group of nano-wires, nanotubes, or different distribution of NPs) (Fig. 6.1) [4]. Precisely, fullerenes (FLNs) (0D), carbon nanotubes (CNTs) (1D), graphene (2D), graphite (3D)—all of them are allotropic carbon NMs having different dimensions. The effectiveness and utility of these NMs not only depend on their respective properties but also methods of generation, such as application of cross-linker, polymerization strategy, and porogen used which determine their porous structure, adsorption, and interaction capacity hence the applicability of these NMs in separation techniques. Some of the properties and advantages of different NPs have been enumerated in Table 6.1.

6.2.1 Carbon nanostructures Several carbonaceous materials in multiple allotropic forms, such as FLN, singlewalled and multi-walled CNTs (SWCNT and MWCNT), graphene, and graphite, have been widely used in pure form and/or with other NMs in numerous separation

102

Handbook of Nanomaterials in Analytical Chemistry

Figure 6.1 Classification of types of nanoparticles on the basis of application in different dimensions.

methods due to some favorable inherent properties, such as high electrical conductivity, pore diameter, pore volume, surface area, nanoscale size, higher surface area-to-volume ratio, high selectivity, affinity, durability, binding capacity, compatibility, better ability of mechanical resistance, chemical and thermal stability, and tensile strength. Moreover, the rich modifiable surface chemistry , according to the requirement, imposes additional advantages to these NMs when the functional groups are added by noncovalent forces such as hydrogen bonding, electrostatic forces, π-π and hydrophobic interactions, and van der Waals forces to control the nanoadsorption process. [5 8].

6.2.1.1 Fullerenes FLNs were first delineated by Kroto et al. [9] which is having sp2-hybridized spherical carbon atoms arranged in hollow carbon cages. FLN-based NMs possess high thermal stability, hydrophobicity, stability to oxidation, and capability for acceptor donor interactions [10] and are arranged in pentagonal and hexagonal rings with formulae C201m. The sp2-hybridization provides strong bonding of these NMs to phenyl groups in analytes. FLNs have advantages of low reactivity unlike silica and alumina, good mechanical and hydrolytic stability which helps to overcome the problem of excessive sorbent swelling usually observed in case of polysaccharide-based separation media and modifiable surface chemistry by adding additional functional groups for specific interactions [11,12]. However, the inherent shortcomings of these NMs include poor permeability and dearth of reactive groups on the surface of the native NMs [13].

Table 6.1 Examples of nanoparticles (NP) commonly used in separation techniques with their properties and advantages. Type of NP

Properties

Advantage

NP as such

Increase surface/volume ratio

Functionalization

Positive charge will retain negative charge and vice versa, group-specific separation Sheet will give mechanical strength Resistance to stressors, such as chemical attack, pH temperature More site for different functionalization, different kinds of bonding interactions Provide noncovalent bonding interactions, work like semiconductor Magnetic force based More retention of one group Vary in reactivity

Help in miniature formation, increase in flow rate provides better filtration Enhance resolution and separation

In form Inorganic NP Organic NP NP with vacant sp, d or f group Magnetic NP As pseudostationary medium Shape

Size of NP and pore size More electronegative ion

Amino groups

Affect adsorption and filtration Hydrogen bonding if solution has electronegative analytes, bind with positive compound Silanol effect suppressed

Better resistance Enhance durability Enhance sensitivity and selectivity but prone to resistant Enhance sensitivity and selectivity Better separation for magnetic nature particle Better resolution, separation, faster, and better peak For example, AuNP-based rods decrease migration times and maintain resolution, faster and the narrower the peak than sphere in CE Membrane-based filtration Affect separation

In CE separated both charged and neutral compound

104

Handbook of Nanomaterials in Analytical Chemistry

6.2.1.2 Carbon nanotubes CNTs were first described in 1991 by Iijima in which sp2-hybridized carbon atoms are assembled with nanometric diameter and the length can be extended up to tens of micrometers in cylindrical shape having good stability [14]. CNTs are either applied as single-walled 1D system (SWCNTs) or in multiple-walled configuration (MWCNTs) for separation of diverse analytes. CNTs can be easily modified to act as conductors and semiconductors depending upon their chemical and physical treatments [10,15 18] and also having modifiable pore size and geometry of pores. These properties along with ability to enhance their adsorption capacity higher than activated carbons [12,17] provide improved retention, resolution, and analysis times for a number of compound classes [12,19 24] making it applicable as sorbents for solid-phase extraction (SPE) and micro-extraction, stationary phases in different chromatography techniques, and as coating material in open tube capillary electrochromatography (CEC) or stationary phase modifier in monolithic columns or pseudostationary phases for capillary electrophoresis [12].

6.2.1.3 Nanodiamonds Similarly, nanodiamonds (NDs) are allotropic carbon nanostructure which can be produced by detonation of explosives in an oxygen-deficient atmosphere and have lower cost of preparation. Micro-dispersed arrangement of these NMs is an additional positive for deployment in chromatographic separation platforms. Furthermore, other advantageous features include hydrolytic stability over the entire pH range and absence of shrinking or swelling in various mobile phase [25] along with sp3-hybridized atoms in these NMs exhibiting unique retention behaviors provide ambience for their application in various separation techniques [25,26].

6.2.1.4 Graphene and graphene oxide Graphene is also an allotropic carbon-based NM having sp2 carbon atoms arranged in honeycomb-like structure. The ultrahigh-specific surface area of these NMs at both the sides due to its sheet-like orientation provides enormous sorption capacity for the analytes. It suffers from the drawback of selfaggregation, low water wettability, and stronger van der Wall force. Graphene oxide (GO) NMs as such or with modifications can be the better alternative to grapheme providing better separation of aromatic compounds including polar amines and steroids, and large biomolecules [27]. Oxidation of graphite leads to generation of GO which can be subsequently reduced to form graphene NMs. Atomic arrangement in hexagonal lattice with oxygen functional groups aids GO to overcome the hitches of graphene on one aspect while maintaining the other common positives of carbon-based NMs render it applicable for various separation techniques.

Separation techniques with nanomaterials

105

6.2.2 Organic polymer based nanomaterials NMs of various organic compounds, such as methacrylates, acrylates, styrene, acrylamide, or cyclic monomers, have been used in separation methods particularly because of their specific interaction properties. Earlier in conventional separation techniques, polymers, such as cellulose acetate, polyesters, and polysulfone (PSF), have been applied but usually suffer from rigidification, poor spatial distribution, easy blocking, etc. [28]. The application of NMs of organic polymers has both advantages and limitations, but their precise interaction properties have rendered them mostly suitable for separation of specific analytes from a complex mixture. Polystyrene latex NPs with quaternary amine-functionalization have been employed for carbohydrate separation using simple electrostatic binding in anion-exchange mode [29]. Another such example of NM-mediated separation system is the application of polyhedral oligomeric silsesquioxane (amine-POSS) NPs dispersed in a polyvinyl alcohol (PVA) matrix membrane for CO2-selective gas separation [30]. Many organic NMs are used as molecularly imprinted polymers (MIPs) where functional monomer and a cross-linker are added to an organic solvent containing an initiator and a template molecule; for example, polymer molecules 1,1,1-tris(hydroxymethyl) propane trimethacrylate and methacrylic acid have been used in different ratios as free moving pseudostationary phase in capillary electrokinetic separations for molecular recognition of analytes [31]. Similarly, NP copolymers of poly(ethylene oxide) (PEO), chiral L-/D-glutamic acid [PEO-b-(L-/D-GluA)10], and chiral L-/D-phenylalanine [PEO-b-(L-/D-Phe)10] have been used for enantioselective or enantiomeric separation [32]. Utility of such polymeric NMs is mostly application specific targeting a particular type or group of analytes thus thorough prior knowledge of chemistry between target and NMs is prerequisite. However, when applied properly, they provide additional benefits, such as easy processability, good permeability, diverse composition range as per analytes, and satisfactory stability over a wide range of pH [33].

6.2.3 Inorganic silica nanoparticles Silica particles are undoubtedly the most widely applied NMs in chromatographic stationary phases which is vividly supported by their ample application in various separation media by worldwide distributed several research groups. Silica NPs provide various advantages, such as high surface area, its availability in various particle sizes and pore diameters, and the ease of surface modification due to the presence of silanes providing wide range of functional interactions [34]. Ease of controlling the size is very useful advantage of these NMs as pore sizes greater than 7 nm are generally required for efficient separation and mass transport in liquid phase, whereas for macromolecule separations, more than 100 nm pore size is required [35]. The innate limitations of silica NPs include their stability at relatively narrow pH range (stable at pH 2 8), inadequate thermal and chemical stability. However, it can be overcome by applying them in association with other material coatings forming core shell microspheres. Incorporation of fumed silica NPs in

106

Handbook of Nanomaterials in Analytical Chemistry

monolithic stationary phase has also increased the efficiency and selectivity in chromatographic separation. Further, it can be used for higher enantioselectivity either in solo or with antibodies for enantiomers separation up to eight pairs than a bare capillary with the same coating [33]. Inorganic silica NPs are also of utility in mixed-matrix membrane-based separation where the hybrid membrane composed of polymeric compound is filled with inorganic particles, such as silica. As, for example, PSF is used as polymer and porous zeolites, carbon molecular sieves or nanoporous silica NPs act as inorganic particle. The technique is used in gas separation as simple polymeric membrane has the disadvantage of upper bound phenomenon which can be overcome here [36] as addition of NPs enhances the separation and increases the free volume because of void formation, it also enhances the thermal stability of separation column.

6.2.4 Metallic nanoparticles Metallic NPs have found their niche of application in separation science due to their inherent properties, including but not limited to ease of production, adorable surface properties, high stability, enhanced adsorption and desorption capability, and unique electrical. They can be used in combination with other metal ions in stationary phases through static electricity [37]. NPs of gold (Au), silver (Ag), copper (Cu), iron (Fe), etc. are most commonly employed, such as CuNPs have been applied in SPE of β-adrenergic agonist [38]. Among all of them, AuNPs are certainly the most popular one because of their biological compatibility, stability, readily availability, higher affinity with thiol group, good solubility, controllable particle size, and narrow size distribution which has facilitated their wide application in various separation techniques from a simple paper chromatography to capillary and microchip electrophoresis including several efficient chromatography platforms [39]. Various other metallic NPs have been attached to the chromatographic layers by electrostatic interactions for separation of analytes by adsorption phenomenon which gives better separation than covalent immobilization; however, stability and reproducibility can be an issue to some extent. Furthermore, metallic NMs have been used as sensors or detectors in several separation techniques as they directly act as electrode or conforms separation phases in electrophoretic partitioning to provide better resolution because of unique chromogenic and electrical properties [34]. Selective adsorption properties of metallic NMs have also been used in separation membranes, such as palladium (Pd) NPs, are used for hydrogen and CO2 separation. Similarly, AgNPs are having advantageous features, such as extremely small size, diverse morphologies, and biocompatibility, which have found application in preconcentration, surface modification of silica monoliths, and as sensors [40].

6.2.5 Metal oxide nanoparticles These NPs are mostly employed for coating of silica NPs to improve the chemical stability of silica particles because metal oxide NPs have high pH stabilities along with proficiency for the ion-exchange separation of small analytes. Oxides of

Separation techniques with nanomaterials

107

zirconium (Zr), titanium (Ti), aluminum (Al), gallium (Ga), iron (Fe), zinc (Zn), etc. are more commonly employed. Zirconia NPs possess the advantages of monodispersity, high surface area, pore volume, narrow particle size, good pore structure and distribution, customizable surface property, better thermal and pH-related chemical stability, and probably the most useful metal oxide NPs to be used in chromatography and capillary electrochromatographic techniques. Being an amphoteric compound, it can exhibit both anion and cation exchange property in different pH media [41,42], thus it has been used for protein separation from various complex sources. Similarly, other metal oxide NPs, such as titania which is having good stability in wide pH and organic solvent range, zinc oxides which can bind with PU by hydrogen bonding to yield better adsorption and stability characters as evident by their use in sweetening of sour gas [43], and alumina which have higher conductivity hence lower resistance in wider pH range along with specific electrostatic and chemical chelating properties, have also been exploited in various separation platforms. Cerium oxide (CeO2) can be employed for its additional property, such as free radical scavenging with a shielding activity and serve as effective antioxidants. Similarly, magnesium oxide (MgO), which is devoid of toxicity, and having limited hydrophilic capacity, Hafnium oxide (HfO2) having thermal resilience, isoelectric point of 7.0, chemically inert, nontoxic particles can also be used for specialized purpose [44,45].

6.2.6 Metal organic frameworks MOFs are NMs comprising linked organic ligands with inorganic centers, usually metals or metal clusters generated by reticular synthesis under solvothermal or hydrothermal mechanism. These NMs possess ultrahigh porosity, high thermal and chemical stability, flexibility to various geometry, and functionality along with adsorption specificity for certain analytes which have been explored in sample enrichment and separation methodologies [46]. Polydispersity and nonspherical irregular shapes are the major drawbacks of MOF which has been circumvented mostly by applying them with silica NPs. Feasibility of chiral separation is an added advantage to the MOF NMs. The application of ionic liquids (ILs) along with silica-based MOF stationary phase has found applicability for separation of hydrophilic analytes.

6.2.7 Magnetic nanoparticles Magnetic NPs (MNPs) inherit several convenient features to aid in separation science, such as simplicity of application, compatible with a variety of materials, ease of surface modification, high selectivity, rapid isolation, and high recovery of analytes by producing an external magnetic field. To improve the sorption properties of these MNPs, various organic or inorganic NMs, such as silica, metal and metal oxides, CNTs, graphene, polymers, MIPs, ILs, and surfactants, are oftentimes incorporated with magnetite (Fe3O4) and maghemite (γ-Fe2O3) which are the most commonly used MNPs. These coated MNPs have found application in

108

Handbook of Nanomaterials in Analytical Chemistry

chromatographic separations, extraction [dynamic SPE, microextraction by packed sorbent, matrix solid-phase dispersion, stir-bar sorptive extraction, solid-phase microextraction (SPME), dispersive solid-phase extraction (d-SPE)] of specific analytes from complex mixtures, preconcentration of analyte, etc. The separation by MNP depends on target molecules, type of sorbent, and interaction of analyte molecules with the surface functional groups which may be due to the following forces: ionic, dipole dipole, dipole-induced dipole, hydrogen bonding, and dispersion force [47,48]. The NM repository is growing rapidly by enrichment with newer ones or introduction of modifications to the existing ones. Therefore continuous fortification of knowledge database is essential for proficient exploitation of these unique materials in state-of-the-art separation methodologies. NMs can be used as preconcentrator for analyte enrichment, for separation of compounds in pure form or present in traces by membranes, electrophoresis, chromatography, and/or lab on chip devices which will be elucidated in subsequent sections.

6.3

Separation techniques with nanomaterials

Separation is the basic mechanism performed in analytical techniques to find out qualitative or quantitative information. It can be done to separate all the chemicals present in complex form of samples for quantitative information about all the materials present or can be done to extract a particular kind of chemical in pure form for qualitative or quantitative analysis. Apart from that, the alternate strategy of enrichment may be employed for proper separation of trace material present by exploiting specific property of targeted molecules. Various techniques based on physical, chemical, or biological phenomenon are applied. The selection of techniques depends upon physical nature, such as shape or size, electrical or magnetic property of target analyte or exploit chemical properties, such as solubility, pH, chemical reactions, phase separation on the basis of chemical nature of analytes, or can be based on biological properties, such as antibody binding, surface marker, and fluorescence property for biological sample preparation. Application of NPs or NMs can be observed in almost every aspect of separation techniques for efficient or economical gain in various applications as documented in Fig. 6.2 and Table 6.2. These techniques include but not limited to membrane-based separation, electrophoresis or magnetic property-based separation, and separation using chromatographic or microfluidics techniques which have been discussed in the following section with suitable examples.

6.3.1 Membrane-based separation Syringe membrane and dialysis membrane are simple examples of such membranebased filters. This is simple, cost-effective, requires low energy, stable under various operational conditions, and faster in operation than other methods like

Separation techniques with nanomaterials

109

Figure 6.2 Application of nanoparticles in various separation techniques: (1) Membrane base separation: MF, UF, NF, and RO; (2) SPE: CSPE, DPSE, and SPME; (3) capillary electrophoresis: CGE, CZE, MEKC, CGE, and CIEF, and CITP; (4) chromatography: HPLC, UPLC, HILIC, LCMS, GC; (5) microfludics and NMR. CGE, Capillary gel electrophoresis; CIEF, capillary isoelectric focusing; CITP, capillary isotachorphoresis; CSPE, conventional SPE; CZE, capillary zone electrophoresis; DPSE, dispersive solid phase extraction; GC, gas chromatography; HILIC, hydrophilic interaction liquid chromatography; HPLC, high-performance liquid chromatography; LCMS, liquid chromatography mass spectrometry; MEKC, micellarelectrokinetic chromatography; MF, microfiltration; NF, nanofiltration; NMR, nuclear magnetic resonance; RO, reverse osmosis; SPE, solid phase extraction; SPME, solid-phase micro extraction; UF, ultrafiltration; UPLC, ultra-performance liquid chromatography.

chromatography with additional benefit of environment-friendly and safety [50]. It acts as a interphase between two phases, works mostly on basic principle where physical forces, such as simple gravity, centrifugal force or concentration-specific diffusion, and magnetic property, are employed to separate them on the basis of reactivity, porosity, pore size, pore distribution, cutoff, contact angle, compatibility, or magnetic or adsorption property of targeted analytes. Good membrane should generate higher and stable filtration flux with lower filtration pressure for efficient separation, high selectivity, and absorptivity for specific analytes. Various types of membrane-based separation techniques are as follows: 1. Microfiltration (MF) which is a low pressure based system for separating large molecular weight suspended or colloidal polymeric materials, mostly employed in the removal of bacteria, flocculated materials, or total suspended solids. 2. Ultrafiltration (UF) is a selective separation method used with 15 100 psi pressure to concentrate and/or purify medium containing high molecular weight materials, such as protein, carbohydrates, and de-ashing. 3. Nanofiltration (NF) is a process where membrane pore size in nano-range leads to specific separations of low molecular weight materials. The application includes separation of

Table 6.2 Applicability of nanoparticles (NPs) in separation of diverse molecules with respective techniques of separation employed. Sl. No.

Techniques

NP/NM

Other material/source

Application

Comments

Ref.

Protein separation in range of 66 115 kDa Protein separation of same size in different pH

Both BSA and gamma globulin separated BSA and bhb separated having same mass but different isoelectric properties Low hydrophobicity decreased the contact angle lead high flux and better antifouling resistance Ultra-fast diffusion times and high-resolution separation, compatibility with biological fluids and low-cost production, exhibit high mechanical strength, low surface energies, and a sharp permeability cutoff at a hydrodynamic diameter of 10 nm suitable for protein separations By gravity efficient separation of bio-lipid-in-hexane/water mixture Enrichment occurs only in only 30 s, with detection limit of 50 fmol. Good for single cell proteomics

[49]

Protein, peptide, and enzyme separation 1.

Membrane

Silicon

Silica

2.

Membrane

Tunable nanotubular carbon block

Copolymer micelles with copper

3.

UF

Carbon nanotube (f-MWCNT) and PVP

S-PES a

4.

Nano-membranes

PLGA

Esin PCGF cured with branched PEI

5.

Hydrogel membrane

pHEMA

Stainless steel membrane

Efficient separation of microalgal bio-lipid

6.

Magnetic bioseparation

Nitrilotriacetic acidcoated MNP

Cell lysates

Histidine-tagged proteins and phosphorylated peptides

Protein separation like serum albumin (66 kDa), pepsin vi (34.6 kDa), trypsin (20 kDa), and (14.6 kDa) Protein sample

[50]

[51]

[52]

[53]

[54]

7.

8.

9.

10.

11. 12.

High-gradient magnetic separation Ion exchange and high-gradient magnetic filtration Magnetic extraction

MNP

Escherichia coli cell lysate

Histidine-tagged green fluorescent protein

Phospholipid-coated colloidal MNP

Mixture of samples

Protein

Functionalized MNP

E. coli lysate

Protein

Metal chelate affinity chromatography Column-based separation Membrane filtration

Mono-dispersed MNP

Different biological sample

Hydrophobic SiNP Alumina nanofiber

[55]

Protein separation and pathogen detection

Can be used for high output for industrial used because of high surface area/volume ratio Effective recovery and separation, high adsorptive capacities Continuous purification, temperature-induced phase separation High sensitivity and selectivity, faster

Sweet potato starch wastewater Different protein mixture

Protein

Enhanced protein separation

[59]

Protein

Large-scale separation for commercial application Faster separation due to the fast mass transport

[60]

Good spectra and identification in proteome analysis

[62]

High affinity, very low abundant can be separated, suitable for LC MS/MS analysis LOD 50 fmol mL21, no acidic media required Enrichment with low as 130 fmol

[63]

Better stability, efficiency Separation efficient after binding with Con A

[66] [67]

13.

Monolithic capillary columns

Hydroxyapatite NP

Separations of a model mixture of proteins

14.

LCMS

HeLa cell

15.

Affinity based

Urine, serum

Small protein and peptide

16.

Human serum

Phosphopetides

17.

Magnetic separation and enrichment Affinity

Biological samples

Glycopeptides

18. 19.

Affinity Selective adsorption

Vinyl-functionalized hybrid monolithic columns Poly(N-isopropylacrylamide-co-acrylic acid) NPs Magnetic core shell NPMagSiO2@SiO2 Magnetic NP Fe3O4@SiO2 @GMANHNH2 Fe3O4 MNPs Fe3O4 MNPs

Protein separation and enrichment of phosphopeptides Proteomic analysis

Concept of proof Concept of proof

Lipase Lactoferrin

[56]

[57]

[58]

[61]

[64] [65]

(Continued)

Table 6.2 (Continued) Sl. No.

Techniques

NP/NM

Other material/source

Application

Comments

Ref.

20.

Affinity chromatographic

Serum

Phosphopeptides

Can be used in enrichment for proteome study or diagnosis

[68]

21.

Metal oxide affinity chromatography Affinity chromatography

Diamond nano-powder immobilized with Fe31 and La31 ions Titanium dioxide NP

Biological sample

Phosphopetides

[69]

Hydrophilic PAA Ti/ TiO2

Mouse liver

Phosphopetides

Faster, high resolution, and high selectivity Detection at fmol mL21 level, higher selectivity, high recovery High affinity and excellent water solubility, better yield, and sensitivity limit 0.4 pg mL21 Excellent extraction, separation, and enrichment with LOD 2 3 10215 M Better separation than C8 and C18 columns and normal ion exchange column Helps to identify 4700 unique phosphorylated peptide, rapid and complete separation Carboxylate groups were the major ionizable ligands, electro-osmotic mobility, 4.0 3 104 cm2 V21 S21 Better performance Bovine serum albumin, carbonic anhydrase, insulin, and ribonuclease

[77]

22.

23.

Affinity based

Boronic acidfunctionalized SiNPs

Human saliva

Trace glycoproteins

24.

Affinity based

Branched PEI acidfunctionalized MNPs

Human saliva

Glycoproteins

25.

Ion exchange

Gold NPs functionalized with thiol group

Monolith column

Protein mixtures

25.

SPE

Titanium (IV)

26.

Open-tubular capillary electrochromatography

SWCNTs-OH

BMA CNT open-tubular column

Peptides

27.

RPLC

CNTs

Silica

28.

RPLC

Gold (Au)

Monoliths

Medium-to-large biomolecules Proteins or peptides

Enrich phosphopeptides

[70]

[71]

[72]

[73]

[74]

[75]

[76]

Metabolite separation 29.

Nanosheet membrane

Molybdenum disulfide (MoS2)

Bilayer of POPE

Phospholipids extraction

30.

Membrane

Silicon-coated CNT

Lipid-1D-nanostructure hybrids

Lipid compound

31.

Boronic acidfunctionalized MNPs TiO2 (titanium oxide) NP

Fructose glucose aqueous solution Olive fruit and oil

Fructose

32.

Magnetic bioseparation Solid-phase dispersion

33.

MS

C60 FLNs, SNPs, and carbon nanotubes

Matrix-free MELDI

MS for low molecular weight

34. 35.

LDI MS Affinity based Utrafiltration

Au nano-shell Fe3O4@SiO2-FPBA SiNPs

Serum Urine Serum

Small metabolites Ribosylated metabolites Metabolomics study

36.

RPLC

MWCNT-modified silica

Column

Separate barbiturates

Silica-magnetite nanoparticles Carboxyl-coated MNPs

Soil

DNA

Mammalian cell

mRNA isolation and supercoiled plasmid DNA

Lipidomic, phospholipids

Lyse bacteria cell wall and extract protoplasm, applicable in single cell omics Maintain structural continuity, retained the lateral mobility of lipid molecules, h high diffusion coefficients Better enrichment, reusable

[78]

MS compatible, better efficiency, and faster Better energy-absorption hence lower matrix ion interference and detector saturation Detection of small metabolites Increased adsorption 6 7 times Effective removal of protein and better coverage in MS/NMR, efficiently, cost-effectively, and work in physiological pH Retain simple aromatics, aromatic acids, or aromatic amines, more easily separated

[81]

Rapid and inexpensive isolation of PCR-ready DNA Simple, inexpensive and efficient to isolate from mammalian cell and Gel. No organic solvents or spin columns needed

[86]

[79]

[80]

[82]

[83] [84] [85]

[12]

DNA and RNA separation 37. 38.

Magnetic bioseparation Magnetic bioseparation

[87]

(Continued)

Table 6.2 (Continued) Sl. No.

Techniques

39.

Affinity chromatography Magnetic bioseparation

40.

NP/NM

Other material/source

Application

Comments

Ref.

E. coli

RNA

[88]

Bacterial plasmid, TNA, genomic DNA, environmental, RNA E. coli

DNA and RNA

Reusable, pH-dependent extraction Versatility and cost-effectiveness

DNA and RNA

Simultaneous extraction

[90]

MNPs functionalized with o-aminopropyl

Saccharomyces cerevisiae

DNA isolation

Allows the adsorption of DNA from a solution

[91]

E. coli

Plasmid DNA

[92]

Monolithic material, stationary phase

Plasmid DNA

Better separation and purification Separate 0.1 10.0 kbp DNA fragments rapidly with high resolution Highest quality and best recovery

Change in hydrodynamic size with change in pH, increased the hydrophilicity, surface smoothness, pore size, and pure water flux After a backwash membrane permeability completely recovered, lower porosity, no adverse impact on the coagulation performance

[95]

Functionalized MNPs

43.

Magnetic bioseparation Adsorption-based magnetic separation Adsorption based

44.

CE

Nano-spine hydrophobic cryo-gel HEC polymer

45.

Anion exchange chromatography

Amino functionalized methacrylate based

41. 42.

Silica-coated MNPs

DNA separation

[89]

[93]

[94]

Pharmacy and other medical application 46.

UF membrane

CS-PAA

PSF

Medical, biological, and pharmaceutical application

47.

UF

MNPs (Fe3O4)

CUF membrane

Many biological sample, magnetic antibody-based separation, removal of bacteria and viruses

[96]

48.

CE

11-MUA functionalized AuNPs

PSP

Biomarker discovery

49.

CE

Chitosan-modified SiNPs

PSP

Biological importance material

50.

CE

CAU-1

Drugs

51.

CE

MOF AlaZnCl

Neurotransmitters and drugs

52.

CEC, HPLC

Methacrylate-based

Monolithic material

Hydrocarbons, caffeine, and several analgesics

53.

Microfluidic CEC

Fused-silica-methacrylate based

Monolithic material

54.

Affinity chromatography

Magnetic SiO2 microspheres

Serum, biological sample

Separation of derivatized amines and green fluorescent proteins Purification of immuneglobulin G

For Parkinson biomarker. dopamine, epinephrine, pyrocatechol, L-3,4dihydroxyphenylalanine, glutathione, and uric acid. Migration time, peak area, and velocity trends were better Auxins, i.e., indole-3-acetic acid, indole butyric acid, 2,4dichlorophenoxyacetic acid, 1-naphthaleneacetic acid with LOD 11 75 μg L21 and correlation coefficients of 0.994 0.999 Aromatic acids, nonsteroidalantiinflammatory drugs, sulfa drugs, and peptide separation with better migration time and peak area Monoamine neurotransmitters and amine drugs separation with better migration time and peak area Excellent chromatographic performance with reduced plate height and minimizing secondary interactions Enrichment of a solution by a factor of 1000 for green fluorescent protein Faster, higher purity and yield

[97]

[98]

[99]

[100]

[101]

[102]

[103]

(Continued)

Table 6.2 (Continued) Sl. No.

Techniques

NP/NM

Other material/source

Application

Comments

Ref.

55.

TLC

Au

Silica gel as stationary phase

Steroid hormones

[104]

56.

Affinity chromatography

Fe3O4/SiO2 core shell NPs

Stationary phase

Histidine-tagged protein purification

57. 58.

RPLC HPLC

SWCNTs MWCNTs

Amine modified silica GMM/EDMA monolith

Monoclonal antibodies For proteins alkyl-benzenes, anilines, phenols, and phenoxyacid herbicides

59.

Reversed-phase UPLC

Silica

60.

HPLC, HILIC

FLN oxide

Rapid and sensitive for progesterone and testosterone in complex biological samples like urine Good selectivity, moderate binding force of tagged proteins and higher capacity and simple in operation Better resolution For wide range of solutes, including enantiomers, π interactions were responsible for retention Very efficient separation sustains very high pressure and stable in pH range of 1 11 Better separation

Environmental water samples LOD (μg L21) 0.0003 0.0095 Tomato, rape LOD (μg L21) 0.005 0.030, 14 types of pesticide

[108]

Silica stationary phase

Ascorbic acid, hydroquinone, resorcinol, catechol, and 4methylcatechol Nucleosides, nucleo-bases, water soluble vitamins, amino acids, and saccharides

[105]

[20] [24]

[106]

[107]

Pesticide separation and other agriculture applications 61.

SPME

MWCNTs

62.

SPME

Fe3O4

Organophosphorus pesticides

SiO2-graphene

Organophosphorus pesticides

[109]

63.

SPE

Zr

CAHF

Organophosphorus pesticides

64.

SPE

MWCNTs

65.

SPE

Fe3O4

Poly(DVB-co-NVPD)

Triazine herbicides

66.

SPE

Fe3O4

Triazine herbicides

67.

SPE

ZnO

SiO2-imprinted cyromazine CF

68.

SPE

Fe3O4

MAAIBL

Organochlorine pesticides

69.

SPE

Fe3O4

SiO2-C18

Pyrethroid insecticides

70.

SPE

Fe3O4

Poly(DVB-co-NVID)

Pyrethroid insecticides

71.

SPE

Fe3O4

MWCNTs-MIP

Pyrethroid insecticides

72.

SPE

Fe3O4

SiO2-graphene

Carbamate insecticides

73.

SPE

Fe3O4

MIP

Carbamate insecticides

74.

SPE

Graphene-modified TiO2

Carbamate insecticides

75.

SPE

Carbon nanotubes

β-Blockers

76.

SPE

Nylon 6 nanofiber

Parabens, steroids, flavonoids, and pesticides

77.

SPE

Core shell magnetic nano-sorbent

Triazine herbicides

Molecularly imprinted polymer

Organochlorine pesticides

Dimetrid-azole

Various source LOD (μg L21) 0.001 0.004 Environmental waters LOD (μg L21) 0.15 0.3 Environmental water samples, LOD (μg L21) 0.048 0.081 Environmental water, LOD (μg L21) 0.25 0.37 In milk, LOD (μg L21) 0.19 1.64 Sea water LOD (μg L21) 0.001 0.002 Pond water LOD (μg L21) 0.001 0.008 Environmental water LOD (μg L21) 0.004 0.19 Fruits LOD (μg L21) 0.0035 0.0072 Fruits and vegetables LOD (μg L21) 0.08 0.2 Fruits and vegetables LOD (μg L21) 0.009 0.012 Environmental water LOD (μg L21) 2.27 3.26 Commercialized by Shenzhen Nanotech LOD (μg L21) 0.5 1.45 recovery 83% 96% Environmental water, retention of phenolic compounds, recovery 23% 126% Food, retention of phenolic compounds, recovery 90% 106%

[110] [111] [112] [113] [114] [115] [116] [117] [118]. [119] [120] [121] [122]

[123]

[124]

(Continued)

Table 6.2 (Continued) Sl. No.

Techniques

NP/NM

Other material/source

78.

SPE

79.

CE

PEGylated magnetic MWCNTs dASNPs

PSP

Food material grade organic acid separation

80.

Dispersive SPME and CE

dASNPs

As adsorbents and PSPs

In food and beverage industry

81.

CE

PSP

82.

CE

SWCNTs with anionic, surfactants Imidazolium-based ILs covalently coated MWCNTs

Biological and flavoring separation Biological and flavoring separation

Aluminum oxide

Stationary phase

PSP

Application

Comments

Ref.

Z-Ligustilide

Asian herbal plants recovery 99% Separated five acid with LOD 7.5, 0.15, 0.23, 0.33, and 10.0 mg L21 for citric acid, salicylic acid, benzoic acid, sorbic acid, and ascorbic acid Four colorants separation with limits of detection for between 0.030 and 0.36 mg L21, and correlation coefficients (R2) higher than 0.9932 Separation of catechins, phenolic acids, and flavonoids Separation is achieved of saponins, phenolic acids, and flavonoids with good linearity (R2 . 0.9990) and high resolution

[125]

n-Hexane, benzene, toluene, tetrachloroethylene, chlorobenzene, ethylbenzene, p-xylene, and n-nonane remain stable when run at 150 C for 8 h under a constant inlet nitrogen pressure of 2.5 psi with small variations in retention times

[130]

[126]

[127]

[128] [129]

Hydrocarbons separation 83.

Micro-GC

Organic compounds

Silicon dioxide (SiO2)

85.

Nano-filtration membrane UF membrane

Polyether-sulfone Nanofiltration membrane Polyimide support membrane

Xylitol from fermentation products Organic solvent

86.

SPE

Fe3O4

PDA

PAH

87.

SPE

Fe3O4

Poly(st-DVBco-4-VBSS)

PAH

88.

SPE

Fe3O4

CNF

PAH

89.

SPE

Fe3O4

SiO2-graphene

PAH

90.

SPE

Fe3O4

MOFMIL101 (Cr)

PAH

91.

SPE

Poly(pyrrole-co-aniline)@

GO/Fe3O4

PAHs

92.

CE

Bi-functionalized SiNPs

As stationary phase

Organic compound separation

93.

CE and SPME

Mesoporous-silica-nanospheres

As adsorbents and column

PAHs and organic small molecules

94.

CE

AuNPs

C18 2

Organic compounds

84.

NIPAM and HEMA

Phase Inversion Method based on molecular weight cut off Solvent nanofiltration (OSN) membranes, from 200 to 1,000 g mol21 was the mol cutoff Environmental water samples LOD (μg L21) 0.5 1.9 Environmental water samples LOD (μg L21) 0.19 3.7 Environmental water samples LOD (μg L21) 0.004 0.03 Environmental water samples LOD (μg L21) 0.5 5.0 Environmental water samples LOD (μg L21) 2.8 27.2 Highest extraction efficiency, LOD 0.003a0.01 ng mL21 Separated both charged including acidic, basic compounds, and neutral compound Analytes alkylbenzenes, anilines, naphthalenes and phenols, PAHs, NSAIDs, and hydroxybenzoic acid isomers were separated very efficiently. Also improve improved extraction efficiency Aniline, 4-toluidine, caffeine and N,N-dimethylaniline separation within 20 min with maximum column efficiency of about 2.5105 plates m21 and extremely high stability up to pH 1 12

[131] [132]

[133] [134] [135] [136] [137] [138] [139]

[140]

[141]

(Continued)

Table 6.2 (Continued) Sl. No.

Techniques

NP/NM

Other material/source

Application

Comments

Ref.

95. 96.

CE CE

AuNPs Ionic liquid-gold NPs

Silica monolith Silica monolithic column

Lead to better separation Enhanced hydrophobic retention to hydrophobic compounds, good peak shape, and high separation efficiency for basic compounds

[142] [143]

97.

CE

GO

Stationary phase

Better migration time and peak

[144]

98.

CE

Fe3O4 SiO2 NH2 and SBA-15-NH2

Separation with better migration time and peak area

[145]

99.

CE

MIL-101(Cr)

Hydrophobic alkylbenzenes Separation of various class of molecules like n, alkylbenzenes, PAHs, aromatic amines, phenols, nucleotides, and nucleic acid bases and basic solutes Alkyl benzenes, polycyclic aromatic compounds Organic acids, gastrodin, vanilla alcohol, and citric acid Various organic and biological samples

[146]

100.

CE

101.

HPLC

C10-quaternary ammonium latex NPs GO

102.

Capillary GC

FLNs

Xylene, chloro-toluene, cymene, aromatic acids, PAHs, and trypsin digested BSA peptides separation with better migration time and peak area Separation with better migration time and peak area Gives pi pi stacking property and hydrophobic effect Coating with NP increase efficiency, thermostability, and showed unique selectivity for analytes

Aromatic compounds Silica microspheres as stationary phases Polysiloxanes stationary column

Nitro aromatic compound C12 C32 alkanes, C1 C10 phthalic esters, PAHs, long-chain fatty acid methyl esters, alcoholic and aromatic positional isomers

[147] [148] [149]

103.

Capillary liquid chromatography

Au

C18

Benzene, naphthalene, 2methylnaphthalene, and acenaphthene

104.

GC

3D graphene-based porous carbon material

Stationary phase

105.

Electro-kinetic chromatography

Cationic NP

PSPs

Various chemicals like isomers of alkanes, alcohols, and phenol, like bromobenzene/methyl hexanoate11n-decane/1bromobenzene1. pDichlorobenzene/decane, nundecane/pdichlorobenzene, methyl octanoate/n-undecane. 11Octanol/methyl octanoate, n-dodecane/1-octanol, naphthalene/n-dodecane, tridecane/naphthalene, 6dibromohexane/n-tridecane, n-tetradecane/1,6dibromohexane, biphenyl/n. 6n-Pentadecane/biphenyl acenaphthene/npentadecane Six alky phenyl ketones

106.

RPLC

MWCNTs

GMA/EDMA monolith stationary phase

Uracil and alkylbenzenes separation

Mechanical and chemically stabile, good peak for acidic and neutral compound but peak tailing for basic 3210 plates m21 and weak polar nature, better separation of wide range of compounds

[150]

Hydrophobic portion of PSP leads selectivity, good where anodic electroosmotic flow is required High endurance up to 6000 column volumes, and long lifetime

[152]

[151]

[153]

(Continued)

Table 6.2 (Continued) Sl. No.

Techniques

NP/NM

Other material/source

Application

Comments

Ref.

107.

HPLC

Carbon nanotube

Amino-propyl silica monolith stationary phases

Phenol, aniline, catechol, 3-nitrophenol, and various alkyl phenols, dinitronaphthalenes, and dihydroxynaphthalenes

Effective isocratic separation of small aromatic compound with best efficiency, sharp and symmetric peaks against normal C18

[154]

Monolithic material, stationary phase

Polar analytes

[155, 156]

Monolithic material stationary phase

Carbohydrates

Good selectivity, no peak tailing, no evidence of swelling or shrinking Efficient separation of seven saccharides

Various inorganic materials

Efficient detection, better spectra

[157]

Acidic compound screening

41 pairs of structurally diverse anionic chiral analytes were separated

[158]

2-Chlorophenol

Soil, recovery 82% 95%

[159]

Microcystins

Environmental water, recovery 94% 103%

[160]

Compounds other than hydrocarbons 108.

CEC HILIC

IEC (microanionexchange chromatography)

109.

LDI-MS

110.

CEC

111.

SPE

112.

SPE

Zwitterionic polymethacrylate based Latex-functionalized copolymers of butyl methacrylate, ethylene di-methacrylate, and 2-acrylamido-2methyl-1-propane sulfonic acid Carbon, silica, and metal NPs Fused-vinyl-benzyl trimethyl ammoniumcyclodextin-based monolithic columns Mixed hemi-micelle MNPs Gold-polypyrrole nanocomposite-coated silica

Stationary phase

[29]

4-Fluorophenoxyacetic acid, 4-chlorophenoxyacetic acid, simazine, 1naphthaleneacetic acid, 2,4dichlorophenoxyaceticacid, atrazine, paclobutrazol, uniconazole, and tebuconazole Dye

113.

SPE

Silica-coated Fe3O4 grafted graphene oxide and β-cyclodextrin

114.

Nanofiltration membrane

Zinc oxide

115.

Nanofiltration membrane

GO

Nano-crystal of cellulose

Dyes filtration, effective for molecular separation

116.

GC

Carbon nanotubes

Instrument efficiency

117.

GC

AuNP

118.

GC

Silica

Rectangular (100 m-deep, 100 m-wide, 50 cmlong) column Multicapillary (25 m-wide, 200 m-deep, 25 cmlong column Rectangular and semipacked (100 125 mdeep, 50 150 m-wide, 1 m-long)

119.

CE

AuNP

Instrument efficiency

Instrument efficiency

Size effect

Vegetable, recovery 78% 114% LOD (μg L21) 0.04 0.29

[161]

NP influence their interaction with dye molecules and membrane surfaces influence their interaction with dye molecules and membrane surfaces Most water flux, evenly distribution of pores with reduced fouling capacity can be active up to 90% after cleaning Incomplete coverage of the channel and high process temperature Extensive characterization, highprocess temperature, and chip-level processing High stationary-phase film thickness variations and applicable to low channel

[162]

Rods decrease migration times and maintains resolution, faster and the narrower the peak than sphere

[167]

[163]

[164]

[165]

[166]

(Continued)

Table 6.2 (Continued) Sl. No.

Techniques

NP/NM

Other material/source

Application

Comments

Ref.

120.

NMR

SiNPs

Instrument

LDI MS Membrane

Plasmonic NPs Alumino-silicate or alumina-germanate

Increase efficiency of NMR by spectral simplification Enhanced performance Mechanically strong, high flux, enhancement in adsorption selectivity

[85]

121. 122.

123.

Membrane

CNT ends with zwitterions

In the solution NMR sample Serum Single layer inorganic nanotubes with large pore diameters in the 10 50 nm range Polyimide

[169]

124.

Membrane

Zeolites

Polyimide matrimid

Gas oxygen and nitrogen

125.

CE

Bovine serum albumin functionalized SiNPs

As stationary phase

Enantiomer separation

126.

CE

Amino-modified SiNPs

Additive to the background electrolyte solution

Enantiomer separation of drugs

127.

CE

ZIFs, a subclass of MOFs

PSP

Isomer separation of organic materials

128.

CE

β-CD-AuNPs

Stationary phase

Enantio-selective

High water flux, 99% rejection of salt ions as block the permeation of ions by charge repulsion and steric hindrance Improve interfacial adhesion and filler dispersion gas separation, volatile material like pheromones Enantiomer separation of propranolol and tryptophan, material readily recycled Separation of four alkaline drugs ephedrine, chlorpheniramine, propranolol, and amlodipine with improved resolution Phenolic isomers (p-benzenediol, m-benzenediol, o-benzenediol, m-nitrophenol, p-nitrophenol, and o-nitrophenol) with LOD 0.44 2.0 mg L21 Efficient enantiomer separation with better self-adsorption and steady at pH range of 3.0 9.2

Metabolites Gas/Vapor-phase and liquidphase separations

Gas/Vapor-phase and liquidphase separations

[83] [168]

[170]

[171]

[172]

[173]

[174]

129.

CE

GO

Stationary phase

Isomer detection

130.

CEC

Silica-based

Monolithic material

131. 132.

CE GC

β-CD-MWCNTs Chiral ion liquidSWCNTs

PSP Ionic liquid stationary phase

Chiral phosphinic acid pseudo-dipeptide Enantioseparation of clenbuterol Enantioseparation

133.

Magnetic field

L-Threonine-MMWCNTS

134.

Nano-HPLC

SWCNTs-polymer-based column

Encapsulation in monolithic column

135.

HPLC

PNA-CNTs

Monolithic column

136.

TLC

HP-β-CD-MWCNTs

Added in stationary phase

137.

Membrane

Poly(amide-imide)/TiO2

Poly(amide-imide) membrane

ALG/ poly(allylamine hydrochloride) NP

Antibody based

Enantio-separation of (DL) mandelic acid

Enantio-separation of etozoline, celiprolol, cizolirtine, miconazole, sulconazole, nomifensine, chlorpheniramine Enantio-separation of 10 amino acids Enantio-separation of clenbuterol Gas separation

O-Nitroaniline, p-nitroaniline, and m-nitroaniline with LOD 1.8 3 1023 2.7 3 1023 mg mL21 Four stereoisomers separation, enhanced plate numbers Large surface area Amino acids, carvone, (DL) leucine, of ( 6 )-N-phenylα-methylbenzylamine. Improves the enantioselectivity by increase surface area and interaction Selection through hydrogen bonds with MMWCNTS which have both magnetic and binding property, recycling the adsorbent and very fast within 10 min Pharmaceutical racemates of various classes successfully separated with little variation in other conditions

[175]

Coating with NP give better and ultrafast separation Better separation

[181]

O2, N2, CO2, H2, and CH4 better separation,

[183]

Identify targeted cell in 1:10,000,000 cell population

[184]

[176] [177] [178]

[179]

[180]

[182]

Target cell separation 138.

Microfluidics

CTCs from whole blood

(Continued)

Table 6.2 (Continued) Sl. No.

Techniques

NP/NM

Other material/source

Application

Comments

Ref.

139.

Immobilization on GO-modified fabric sheets

GO

Anti-EpCAM antibodies

CTCs

[249]

140.

Magnetic separation columns

Super-paramagnetic NPs

HIV-Tat peptides

Hematopoietic and neural progenitor cells

141.

Fluorescent base selection Single-cell mRNA cytometry Sucrose gradient, centrifugation

Magnetic silica coated core shell NP Sequence-specific NP

HER-2 antibody

Breast cancer cell

RNA, magnetic particle

Clinically important cell

CBB-labeled NPs

Subcellular components

144.

Size-based separation

Metastatic cancer cells

Size-based separation

[189]

145.

Confocal microscope and flow cytometry

Four successively narrow arrays of parallel channels ranging from 20 μm down to 2.5 μm in thickness MNPs

Visual dyes like Coomassie Brilliant Blue R250 or antibody PDMS, poly (dimethylsiloxane fabrication)

Increase efficiency by 10% 25% than conventional method, low-cost, easy-to-fit, and disposable Increase efficiency, not affect cell viability, differentiation, or proliferation Immobilization and rapid biological separation Clustering and trapping of target cell Efficient

Antibody conjugation

Lymphoma cell separation

[190]

146.

Immuno-magnetic cell sorting

Anti-CD45 antibody

Hepatocellular carcinoma cells

In a mix population very sensitive detection, quick isolation with more than .95% capture efficiency Fast within 30 min, efficient in heterogeneous sample

142. 143.

Magnetic nano-spheres

[185]

[186] [187] [188]

[191]

BMA, Butyl-methacrylate; CE, capillary electrophoresis; Con A, concanavalin A; CS-PAA, chitosan polyacrylic acid; CTC, circulating tumor cell; dASNPs, diamino moiety functionalized silica nanoparticles; FLN, fullerene; GC, gas chromatography; GO, graphene oxide; HEC, hydroxyethyl cellulose; HEMA, 2-(hydroxy) ethyl methacrylate; IL, ionic liquid; LDI MS, laser desorption/ionization mass spectrometry; LOD, limit of detection; MNPs, magnetic nanoparticles; MOFs, metal organic frameworks; MS, mass spectrometry; MUA, mercaptoundecanoic acid; MWCNTs, multi-walled CNTs; NIPAM, N-isopropyl-acrylamide; NP, nanoparticle; NSAIDs, nonsteroidal anti-inflammatory drugs; PAH, polycyclic aromatic hydrocarbons; PCGF, poly[(o-cresylglycidyl ether)-co-formaldehyde; PEI, polyethyleneimine; [P(HEMA-VPBA)], poly(hydroxyethyl methacrylate-co-vinyl phenyl boronic acid); pHEMA, poly(2-hydroxyethyl methacrylate); PLGA, poly(D,L-lactide-co-glycolide); POPE, palmitoyloleoylphosphatidylethanolamine; PSF, poly-sulfone; PSP, pseudostationary phases; PVP, polyvinyl-pyrrolidone; RPLC, reversed-phase LC; SiNP, silica NP; SPE, solidphase extraction; S-PES, sulfonated polyethersulfone; SPME, solid-phase microextraction; SWCNTs, single-walled CNTs; TNA, total nucleic acid; UF, ultrafiltration; ZIFs, zeolitic-imidazolate frameworks.

Separation techniques with nanomaterials

127

organic from inorganic, removal of organic contaminants, smaller compounds, such as glucose, from its compound mixture of salt, etc. 4. Reverse osmosis (RO) is a high pressure, energy-efficient water separation method used for desalination and concentration.

Polymeric materials are most commonly used for membrane formations as they are advantageous due to their economics, pore size and density, and specific characteristics required for separation of target analytes. However, these materials often suffer from limitations, such as lower chemical attack resistance, mechanical strength, and tolerance of pH extremes and oxidation, but the application of inorganic membranes which comprises another popular group of materials has advantages in these aspects [192]. But they have other constrains in terms of cost and poor pore size distribution. Major limitations of classical membrane-based separation technique include the issue of sensitivity, membrane clogging effect, or reusability. Clogging or membrane fouling is a foremost problem as solutes attach onto the membrane surface or into the internal structures creating additional barrier or block the membrane pores hence raising the trans-membrane pressure and lowering the permeate productivity leading to ineffective filtration and shortening of life cycle of the membrane filters. However, several important routine molecular biology works follow the path of membrane-based separation techniques, such as isolation of DNA and RNA from biological sample, or concentration of protein in native phase, etc.; furthermore, gas separation or separation of trace elements in sample, such as water and waste, application of dialysis membrane for removal of salts and low molecular weight solutes, or as artificial kidney or liver (dialysis), follows the similar separation process. Various NMs are being employed to obtain better results in separation of aforementioned molecules by using hybrid membrane staking advantage of both organic and inorganic membranes. Such materials in general fulfill the requirement of ideal membrane, such as high permeability, high and stable flux, excellent rejection of foulant materials, cost-effectiveness, durability, strength, and reusability. Various NP-based membranes have been employed to achieve desired results by exploiting the additional advantages, such as attached chemically active groups and large external surface area due to unique properties of NPs; for example, silica NPs incorporated into poly(vinylidene fluoride) membranes withstand higher temperature, produce better selectivity, and higher diffusivity [193]. Similarly, PSF/polyether sulfone and chitosan NP-based membrane are also preferred due to their resistance to chemicals, mechanical and thermal stability, good physicochemical stability, wide pH range stability, and solubility with NPs [95]. Chitosan/Zinc oxide NP-based membrane not only has higher antibacterial action which may be desirable in processing biological samples but also exhibits good mechanical properties [194]. Silica NPs in PSF membranes exhibit enhanced gas permeability [36]. Enhanced porosity, better pseudo-steady-state permeability, and lower flux decline have been achieved through polyethersulfone/aluminum oxide-based membranes [195]. However, aggregation and dispersion phenomenon due to surface interaction is a major problem in such inorganic NP-based membranes which can be controlled

128

Handbook of Nanomaterials in Analytical Chemistry

by tuning the concentration of NP and ionic strength. Currently, it has found several applications such as ultrathin porous membrane made up of nano-crystalline silicon having 15 nm thickness and pore size in the range of 5-25 nm (Striemer et al., 2007), has been used for separation of protein sample of biological origin. Similarly, AuNPs are applied in customizing 6 μm thick polycarbonate gold membrane with functionalized thiol groups for improved separation of same-sized protein under different pH [196], but it suffers from low pore-density problem. Similarly, tunable nanotubular block copolymer with thin nanostructure top layer of copper has been employed to separate protein of same mass and found to have uniform pore size and high pore density with extremely high water flux value because of the thinness of top NP layer which has overcome the drawback of the abovementioned methods [50]. Similarly, oxidized poly(pyrrole) containing AgNP-based membrane has been employed in olefin separation [197] where silver facilitates transportation of components and form complex with ethylenes. Similarly, AgBr nanocomposites polymer-based membrane is used for separation of olefins because of its high resistivity to acetylene [198], but it has not been used in biological sample separation as it induces DNA damage and cell apoptosis. Zirconium oxide incorporated in polyvinylidene difluoride (PVDF) membrane has been used in UF which increase the permeate flux while silica NPs are more commonly employed for separation of biological materials, including biotin avidin, antigen antibodies, peptides, proteins, and DNA because of their high surface area, fine suspendability in aqueous solution, and relatively environmentally inert nature [199]. Similarly, incorporation of silicon dioxide (SiO2) NPs enhances membrane flux and hydrophilicity in polyethersulfone NF membrane which is commonly used in separation of fermentation products. GO and cellulose-based nano-filter membranes produce high water flux and having evenly distributed pores with reduced fouling capacity than normal commercially available filter membranes [200]. Similarly, carbon-based NPs are used for desalination either by simple diffusion or by RO to make analyte free from salt or enriched in minimum salt environment as per requirements. CNT channels provide frictionless, controlled pore-sized membrane which facilitate fast transport of water due to high water flux and exceptional salt ion rejection capability [201] but suffer from lack of high selectivity. It can be overcome by metallic nanotube-based membrane. Similarly, glassy polymer based membrane with NPs, such as zeolite, work on principle of size exclusion effects and selectivity in elastomers because of difference in kinetics and solubility of analytes and higher permeability which are being used for dehydration of organic/water mixtures and separation of organic vapors from noncondensable gases [170,202]. Recently, 2D NP-membranes, such as graphene-based materials (GMs), MoS2, MXene, MOFs, and covalent organic framework nanosheets, have been constructed and applied for various applications [203]. GM has been successfully used in gas separation and water purification. These NPs can be used in membranes as surface coating, to form ultrathin laminar structures by layer-by-layer assembly along with functionalization of sheet by covalent bonding, etc. Application of NPs can be useful further in responsive membranes which have the capability to switch its property, such as

Separation techniques with nanomaterials

129

temperature-dependent selectivity or membrane, whose response changes during electrochemical response, photo-response, pH, and ionic strength response [204].

6.3.2 Solid-phase extraction technique Preparation of samples for analysis includes various methods, such as filtration, precipitation, pH adjustment, enrichment, derivatization, selective extraction, and fractionation, for isolation of the target analytes. Among them, SPE is a popular miniature technique applied in analytical science for rapid extraction and preconcentration of trace analytes with fair degree of advanced automation which increases the probability of repeatability and selectivity. This extraction technique provides ease of clean-up and concentration where analyte and interferes present in liquid or gaseous matrix (mobile phase) are separated by sorbent solid phase (it can be polymer lining, hollow fiber, composite materials) relying upon the specific affinity property of targeted molecules toward the sorbents. The general step of performance includes conditioning of sorbent phase followed by loading of mixture to be segregated in solution or gaseous phase where targeted molecules are adsorbed on sorbent media while rest are percolated out, the impurities are washed down, and the targeted molecules are detached subsequently and collected during elution steps. Here, ionic, magnetic, hydrophobic, or polar interactions are used for attachment of target on sorbent media. To increase selectivity and sensitivity and to reduce time, coast, and fouling event, the NMs have been widely used in conventional and several variants of SPE techniques [205].

6.3.2.1 Conventional solid-phase extraction The technique employs capturing of target analytes present in liquid or gaseous phase by using the sorbents packed into a column. The application of NPs in SPE not only possesses several advantages, such as large surface area, easy functionalization, high adsorption capacity, enhanced specificity, and reusability, but also has certain limitations, such as high back pressure in the SPE column, low selectivity, formation of aggregates, and potential leakage from the column [48]. As an example, MWCNTs have been used for the determination of drugs in river and wastewaters [206]. Similarly, MWCNTs/PVA cryogel composite has yielded high adsorption ability, porosity, and extraction efficiencies (91% 99%) than simple MWCNT that has been employed for separation and elution of polycyclic aromatic hydrocarbons (PAHs) from water [207]; however, the beneficial effect of nano-intervention is unequivocally accepted over traditional SPE media. Carbon-based NMs are mostly being employed in conventional SPE because of higher surface area, functionality, and number of electrostatic interaction forces, such as dipole-dipole, hydrogen bonds, π π stacking, dispersion forces, and dative bonds, and hydrophobic interaction has bestowed them as superior adsorbent for SPE.

130

Handbook of Nanomaterials in Analytical Chemistry

6.3.2.2 Dispersive solid-phase extraction This is modified SPE in which capturing of target molecule is carried out by dispersing the solid sorbents in the complex solution containing the analytes followed by centrifugal separation of the adsorbent containing the captured analytes and their subsequent elution [48]. MNPs are most commonly used in d-SPE technique which is advantageous to conventional SPE in terms of faster capturing, large volume capacity, no blockage, and devoid of high back pressure issue. Magnetite (Fe3O4) and maghemite (γ-Fe2O3) are the most frequently used MNPs in d-SPE which can also be termed magnetic solid-phase extraction (MSPE). These MNPs can either be applied alone as observed in the separation of nerve agents from water sample or in conjugation with other NMs, such as silica-coated MNP which has been applied for polycyclic aromatic hydrocarbons (PAHs) extraction from water samples [95,207 209]. Extraction of various sulfonamide antibiotics from water samples has also been achieved using this method [210]. Higher adsorption capacity of the sorbent material is ideal for such technique like graphene-based MNPs have been used for identification of carbamate pesticides residue in tomatoes [211]. MNP layered over core shell made by polydopamine [212], poly(divinylbenzenecometacrylic acid) [213], and palmitate [214] has also yielded better result in estrogen extraction from water. Similarly, another group of MNPs, such as CTABMNPs [215] and hexadecyldimethyl amine-MNPs [216] which are primarily surfactant NPs, has been used for isolation of anionic materials like perfluorinated compounds. Another example of such MNPs is europium and terbium-coated NPs that have been used in MSPE for extraction of tetracyclines and quinolones from various samples. Further advantage of this technique is its compatibility with downstream analysis through chromatography or mass spectrometry (MS)-based platforms [48]

6.3.2.3 Solid-phase microextraction This is mostly employed for volatile material extraction and compatible with GC MS; however, other applications are also observed. In this technique, sorbent solid phase is coated over a needle-like wire/fiber structure fitted in a syringe to look like a pen which is opened to take the needle out and is immersed in the sample or inserted into the head space for extraction of the analytes from a mixture of gasses (environment) or from volatile liquid followed by withdrawal of the NPcoated needle containing enriched analytes and their subsequent thermal desorption for GC or elution by suitable liquid for LC analysis [48]. Various NPs have found application in this technique which has affinity to particular compounds, such as sol gel-derived Fe3O4/SiO2/TiO2 core-double shell nanocomposite has been employed to concentrate on nonsteroidal anti-inflammatory drugs from human hair [217]. It possesses additional advantage of being plug and play-type instrument which is very handy. Similarly, MWCNT has been used to analyze parabens, such as methyl, ethyl, propyl, and butyl paraben, in cosmetic products with a range of detection

Separation techniques with nanomaterials

131

0.5 2.1 mg L21 [218]. Arsenic from environmental sample has been concentrated by hemicellulose funtionalized CNT-based sorbent with limit of detection (LOD) up to 2 ng L21 [219]. These carbon-based NPs increase preconcentration of both organic and inorganic compounds through chelation and reduce molecular aggregation. Functionalization with different groups further enhances their selectivity and specificity, such as cationic surfactant functionalization to oxidized CNTs leads better retention of metaloxyanions, whereas incorporation of anionic surfactant like sodium dodecylbenzene sulfonate leads extraction of positive compounds. As for example nickel ion extractions, cadmium enrichment, is achieved by L-cysteinefunctionalized CNTs; copper, nickel, zinc, and cobalt enrichment can be achieved by L-tyrosine functionalized CNTs which can be further concentrated and eluted by changing pH of the solution [220]. Similarly, Fe(III), Co(II), Ni(II), Cu(II), Zn(II), and Pb(II) enrichment have been performed by ethylenediamine-modified GO NPs [221]. So enormous utility of various kinds of NPs in SPE analysis of wide array of samples, such as pesticide, drugs, various gases, organic and inorganic compounds, complex samples like contaminated water, frit and other biological samples, soil, etc., has been vividly established with enhanced selectivity, high adsorption capacity, and low LOD which has been accounted in Table 6.2.

6.3.3 Capillary electrophoresis Since the introduction of first high voltage CE system by Stellan Hjerte´n in 1967, followed by first “modern” CE experiment in 1981 by James Jorgenson and its first application in DNA isolation by Barry Kargerin 1988, even in current era of automation, capillary electrophoresis has maintained its relevance and popularity in separation science throughout the ages. It is a rapid analytical technique using submillimeter diameter capillaries for separation of diverse materials by applying electric field. Target analytes in mobile phase move toward electrodes according to their charged nature and get segregated by electrophoretic mobility under applied electric field. Various modifications of CE have been introduced as CE variants, such as CEC, capillary zone electrophoresis (CZE), micellar electrokinetic chromatography (MEKC), capillary isoelectric focusing (CIEF), affinity CE, and capillary gel electrophoresis (CGE), to obtain better resolution by exploiting specific properties of target analytes. In CZE, cocktail of analytes gets separated directly on the basis of charge on the molecule by electrokinetic force generated under applied electrical field, and partitioning efficiency is inversely influenced by the viscosity of solvent and radius (size) of the atoms. In CGE, the separation occurs on the basis of size of analytes under applied electric field through a gel-based separation media, while in MEKC, solutes containing analytes are partitioned between bilayer micelles and the solvent. The micelles with negative charge will retain the positive charged analytes for a longer duration, whereas negatively charged molecules will pass first followed by neutral charge analytes because of lesser retention times. This property of retention can be modified by changing pH, concentration of surfactant, additives, and coating materials of capillary inner wall to achieve better separation performance. CEC imposes additive advantage of chromatography and

132

Handbook of Nanomaterials in Analytical Chemistry

CE where separation occurs due to partitioning between mobile and stationary phase along with charge difference of the analytes, both can act as solo or in combinatorial manner. Extensive application of CEC in biomedical science is due to its attributes providing cumulative advantage in terms of selectivity of HPLC and efficiency of CE. The CIEF technique leads to separation of molecules in different pH gradient where molecules acting as zwitter ion get separated at their respective isoelectric points thus resembling 2D-electrophoresis in this respect. It is mostly undertaken for amphimetric compound separations, such as protein and peptide [222]. Introduction of NPs in CE was pioneered by Wallingford and Ewing in 1989 for separation of catecholamines using sulfonated polymeric NPs by electrokinetic chromatography [223]. The NPs have found their niche in CE-based separation techniques as they enhance the separation efficiency by reducing mass-transfer resistance, improve the resolution and migration times, provide differential mobility from EOF, prevent uncontrolled aggregation, facilitate their stability by providing large area-to-volume ratio, interact specifically with mobile phase analytes when used as background electrolyte, and their customizable surface functionality improves the selectivity of separation mechanisms [224]. Multifaceted applications of NMs in CE and microchip electrophoresis generally include capillary coatings, dynamic pseudostationary phase component, packing materials, or surface modifier of monolithic columns. The beneficial effect of NPs can be exemplified by application of AuNPs functionalized with 11-mercaptoundecanoic acid as pseudostationary phase leads to reduction in peak areas due to nonspecific interactions (i.e., hydrogen bonding and van der Waals interactions) and leads to better resolution for positive charge particles [97]. Various other biological applications include detection and isolation of C-reactive protein by modified MNPs [225]; separation of organic acid from beverage and fruit by diamino moiety functionalized silica NP [126]. Despite several lucrative advantages of nano-interventions in CE-based separation, certain bottlenecks are noteworthy of mention. High back pressure, tedious column packing, and frit fabrication are major difficulties encountered in NP-packed separation columns. Limited stability of NMs in background electrolytes (BGEs) and interference in detection process creates obstacles for NPs use as pseudostationary phase component. Immobilization of NPs nonpermanently with capillary wall by static or dynamic coating or by covalent binding can facilitate to overcome those obstacles. Physical adsorption is the common way for static coating whereas electrostatic or magnetic interaction of the NPs incorporated into BGE generates dynamic coatings. Covalent immobilization relies upon the surface functionalities of the NMs or incorporation of NPs in monolithic columns. At the era of single cell technology, microchip CE is a useful tool for analytical intervention of nano to femtoliter sample volume. Small size and high surface-to-volume ratio with enormous surface functionalities of NMs have perfectly fit into the requirement of microchip CE. More importantly, irreproducible separation patterns due to uncontrolled EOF and adherence to the microchannel surface are the key problems of microchip CE which can be precisely addressed by the NMs. All types of the aforementioned NPs have been used for diverse applications which have been enumerated in Table 6.2.

Separation techniques with nanomaterials

133

6.3.4 Chromatography Although “chroma” has lost its significance in due course of evolution of chromatography, but historically as well as practically it has remained as a colorful technique occupying the center stage of separation methodologies from its introduction in 1903 by Russian botanist Mikhail Tswett to till date. Advancement in material science and analytical platforms has also enriched the basic chromatographic technique to flourish as several variants to satisfy diverse analytical requirements. For example, separation through CEC technique and lab on chip concept has evolved to handle ultralow sample volume with better resolution and speed of analysis. Major shortcomings of conventional chromatographic techniques include higher reactivity and retention of some groups, swelling and shrinking of column, poor reusability, greater void volume, higher sample requirement, low hydrolytic stability, and in some case poor mechanical stability [26]. Moreover, cutting-edge separation platforms demand more sensitivity, versatility, and improved detection system. NPs have the potential to fit in all the grooves due to their high porosity, diverse surface chemistry for specific molecular interaction, high surface area-to-volume ratio, unique thermal, mechanical, electronic, and biological properties rendering them applicable for various LC as well as GC platforms.

6.3.4.1 Liquid chromatography The attachment of NPs can be done by electrostatic interactions, such as binding of gold, zirconia, titanium oxide, and latex NPs onto silica or organic monolith, or noncovalent interactions can also be utilized to adsorb NPs onto or within stationary phase, such as incorporation of SWCNTs or MWCNTs on silica or organic monolith. Similarly, NPs can be shelled inside silica-based stationary phase, such as Fe3O4/SiO2 core shell NPs, or can also be entrapped in support phase. Furthermore, they can directly be used as support medium like NDs used in normal-phase LC [34]. NPs have found multiarrayed utility in every LC variants, for example, graphene-based stationary phase that usually exhibits improved selectivity, sensitivity, and robustness under extreme pH conditions can also be used as anion exchanger when functionalized and coated with polymeric NPs providing excellent separation for inorganic anions, organic acids, carbohydrates, and amino acids with improved reproducibility [226]. Similarly in affinity-based chromatography matrices, cryogel with NPs has been used to separate biological molecules like protein separation by embedded Fe3O4 NPs that can also be employed for separation and removal of trace of As(III) from solution [227,228]. Such system is convenient to obtain proteins in native form by retaining their functionality and activity. In another application, SWCNT-based column has been used for LC separation of peptides efficiently which was not possible by normal C18 column whereas MWCNTs have been employed for separation of several aromatic compounds in silica microsphere-based stationary phase [12]. They have also been used in capillary LC with benzyl methacrylate monolithic column for improved partitioning of mixtures of ketones and phenols [229]. Gold NPs have been used as solution in paper chromatography for clearly distinct and detectable paper coloration for protein band detection [230].

134

Handbook of Nanomaterials in Analytical Chemistry

NPs are also used for RPLC partitioning of compounds into a nonpolar stationary phase; for example, hydroxyl-MWCNT layers on silica NPs have been successfully applied in RPLC for better retention and separation of organic acids, amines, substituted aromatic compounds, and polyaromatic hydrocarbons [23] or to separate barbiturates and retain simple aromatic compound, such as aromatic acids or aromatic amines [12]. Attached MWCNTs on polystyrene-divinylbenzene beads have also been employed in HPLC as stationary phase to get better endurance both in term of durability and stability at wide pH range with satisfactory resolutions [231]. Similarly, the unique inherent properties of MOF particle have rendered them as a preferred media for HPLC separation of wide array of compound including PAHs, hormones, pesticides, and pharmaceuticals. Layer-by-layer synthesized NDs have been applied in RPLC for separation of series of alkylbenzenes, pesticides cyanazine and diazinone but suffer from limitation regarding stability of the column [219]. Metallic NPs, such as gold with n-octadecanethiol, has been employed for effective separation of small organic compounds (e.g., benzene, naphthalene, 2methylnaphthalene, and acenaphthene) with improved partitioning performance and also provide better mechanical and chemical stability [150]; the same has also been successfully applied for effective separation of acidic, basic, and neutral organic compounds with around 66,500 plates m21. Silica NPs have been proficiently utilized in reversed-phase ultra-performance liquid chromatography (UPLC) for separating biological organic metabolites with the efficiency of 500,000 plates m21 and can also sustain very high pressure up to 50,000 psi [106]. Similarly, zirconia and titanium oxide NPs have also been used as reverse phase in LC for effective separation of organic compounds having advantage of narrow pore size distribution, high surface area, and a high pore volume along with ample chemical stability [34] Besides reverse phase application, NMs have also been employed in normalphase LC as well as in hydrophilic interaction LC mode (HILIC) for better separation of polar compounds with improved sensitivity and selectivity than normal chromatography columns. Immobilized SWCNTs over silica column have produced better resolution, larger retention, and better durability of column [34]. Better efficiency and higher retention were achieved by using ND as normal-phase supports for separation of alkylbenzenes [26]. Increased retention and better separation have been documented for aminopyridines as AuNP-adsorbed silica column is employed, while application of thiol-activated GO-modified silica has yielded better separation of alkylbenzenes, isomerides, amino acids, nucleosides, and nucleo-bases [34]. Further, two layers of AuNP coating have generally provided better separation in monolith stationary phase. Similarly, zirconium NP coated on silica in LC has depicted 5000 plates m21 yielding better separation of neutral aromatic compounds (benzene, toluene, xylene, biphenyl, and naphthalene) and nitroaniline isomers.

6.3.4.2 Gas chromatography GC is a reliable and powerful method for the separation of low-boiling point analytes in gaseous forms but it is bulky, expensive, time-, and resource-intensive thus necessitates customization of micro-GC system which requires specially

Separation techniques with nanomaterials

135

designed columns. Further drawbacks, such as very strong retention and high porosity of activated charcoal-based system, polar compound retention, and thermal instability, are major concerns of GC platforms. Column made by integration of solid-adsorbent materials (monolayer-protected gold) [165], CNTs [164], silica NPs [166,232], AuNPs [200], graphite [233], and most recently MOF particles has been used for the purpose but suffers from drawback like low-yield, high processing temperatures and voltage, and monolithic integration [130] which is overcome by metal-oxide-semiconductor complementary metal-oxide-semiconductor (CMOS)compatible coated wafer-level facile columns. Atomic layer deposition of aluminum oxide NP-based semipacked columns has found to be stable in composition at high temperature and after multiple injections with excellent separation [130]. CNT (SWCNTs)-based columns have more diversity in improving enantioseparations than normal column [215]. MWCNT-based packed columns have been used for better separation of various organic materials, such as aromatic, halogenated and alkane hydrocarbons, alcohols, ketones, esters, and ethers [234]. Silica NP-based columns have been found to be suitable for separation of nonpolar compounds, polar or organic compounds, and even isomers efficiently [235] due to large surface area and highly dispersed behavior. Graphene has been utilized as stationary phase in GC, yielded better resolution and retention due to its weakly polar nature, π π interaction, and hydrogen bonding that leads to higher plate no 3100 plates/m for n-dodecane at 120  C [236]. GO nano-sheets have also been used in GC for better separation of volatile aromatic or unsaturated organic compounds, including alcohols and aromatic compounds, when used in fused silica capillary column having cross-linking agent 3aminopropyldiethoxymethyl silane [237]. This was possible for GO because of its higher surface area and stability at higher temperature with high adsorption ability due to hydrophobicity, hydrogen bonding, and π π interaction. Availability of extraordinary high surface areas, multiple active sites for multiarrayed interaction along with distinct shape selectivity, has rendered MOFs as one of the most popularly used modifier in GC columns, particularly for the separation of isomers and racemic mixtures. Application of NPs is not limited to different chromatographic phases, rather they are widely being employed in several detectors to increase the sensitivity of analyte detection. Monolayer-protected AuNPs have been used with microfabricated optofluidic ring resonator for improved detection of volatile organic compounds [238]. Similarly, Chen et al. adapted the same approach to create a monolayer of AuNP-lined inside microfluidic glass capillary, to form a novel chromatographic detector for a conventional GC column which was more sensitive at lower temperature and lower flow rate. Furthermore, it consumes less energy and can operate with air as carrier gas [239]. To enhance detection efficiency of GC platform, Au@SiO2 NPs arranged in layer by layer have been applied in localized surface plasmon resonance-based detector by Lin et al. [240], where LOD was only # 20 ng for cyclohexanone and m-xylene. NPs have also been used in chemiresistor-based detectors and also in arrays for micro-GC [241].

136

Handbook of Nanomaterials in Analytical Chemistry

6.3.5 Microfluidics Microfluidic-based separation has often undertaken assembling of multiple separation steps into a single platform for the development of lab on chip device. The general advantages are that it requires very mere amount of sample which is extremely valuable for single cell techniques and other precious samples. Additional advantages include minimum input requirement, rapidity, multiplexing, negligible dead volume, robustness, possible integration with any detection system, and reduced noise improved sensitivity. The application of NPs has been proved to be beneficial for every said aspects to improve the performance [54]; such as telechelic poly (N-isopropylacrylamide) polymer chains and γ-Fe2O3 NPs have been as dual magnetic agents for making temperature-responsive microfluidic device for better separation of target molecules [242]. Similarly, microfluidic device with MNP has been developed to isolate cells, mostly bacterial separation from blood with 100% clearance [243]. Furthermore, magnetic nanoparticle clusters had been employed to develop microfluidic devices with 3D-printed channels for better capture of Escherichia coli [244]. The application of microfluidics is not only limited to separation of biological cells or materials but also being used for separation of different class of compounds with faster rate as chromatography and electrophoresis can be performed on the same platform and it is compatible with downstream analytical tool MS. Some other details of its application have been documented in Table 6.2. The controllable size of NPs and their rich surface properties have enriched microfluidics technique to develop as a diversified platform for multifaceted application. For example, change of size in microfluidics device is more controllable hence simultaneous separation of gene/DNA, protein, virus, and mammalian cell is possible at the same platform by pore size control though their size varies considerably [245].

6.4

Potential applications of nanomaterial-based separation techniques

The diversified application of NMs in separation science is not only restricted to isolation of macromolecules, such as DNA, RNA, proteins, and peptides, but also includes separation of specific kind of cell from population of cells or antibodies, isomers, etc. This becomes possible due to endless benefits of nano-interventions in separation science which includes but not limited to economics of isolation, rapidness, purity, sensitivity, selectivity or robustness, and durability of these approaches than other conventional techniques. Some major biomedical applications of NMbased separation techniques have been mentioned here and the other details have been depicted in Table 6.2 with respective platforms used.

6.4.1 Isolation of specific target cells from a population Most of the specific cell isolations from population of cells have been efficiently done in microfluidics chip or by FACS employing NP-conjugated antibody specific

Separation techniques with nanomaterials

137

for the target cell and magnetic capture of the γ-Fe2O3 MNPs has become popular for isolation of molecules, cells, bacteria, or viruses from a given complex biological samples [246] by using dual-encoded bioprobes made from NPs and fluorescent materials leading to high-throughput and multiplexing cell isolation. Xu et al. [247] applied iron oxide MNPs to separate tumor cell using anti-HER2 antibody (a membrane protein over expressed in cancer cell) from whole blood. This technique has achieved cell separation even in 1:10,000,000 ratio. In another technique, circulating tumor cells (CTCs) from whole blood have been isolated and enriched by using biodegradable nano-film using alginate and poly(allylamine hydrochloride) NPs in microfluidics platform [211]. The technique is capable to separate various cell lines like cancer cell lines such as PC-3, LNCaP, DU 145, H1650, and H1975 of cancer by coating the nano-film with materials having affinity to such cell lines. Similarly, antibody-functionalized magnetic nano-wires have been used for isolation and detection of CTCs from 250 μL of blood sample from human metastasis case with 100% efficiency [248]. Functionalized GO on polyester fabric sheet has been employed to target CTCs in human sample with increase in efficiency and sensitivity which is further cost-effective, easy-to-fit, and disposable method [249]. Such selection is not only restricted to tumor cell but isolation and enrichment of other kind of cells but can also be possible. Labeled with HIV-Tat peptides and superparamagnetic NPs can be used to isolated progenitor cells which may be hematopoietic or neural from bone marrow cells. In another kind of method employing single-cell mRNA cytometry, cells of clinical importance are isolated from sample by exploiting expression of specific RNA in the target cell using sequence-specific MNPs. Such kind of isolation can be performed for various kinds of clinically important cell for diagnosis and study purpose [187]. Isolation of such targeted cell is not only helpful for diagnosis, prognosis, and control of disease but also such cells can be used for understanding of different disease mechanisms or underlying pathophysiological processes. Such separation methods can even be applied for subcellular components.

6.4.2 Nucleic acid separation Separation of nucleic acid from the complex biological sample is of multiarrayed practical utility. The expression of RNA is rapidly regulated with the change in stimuli and environments. So any suitable isolation method with least impurity and breakage or loss with least coast involvement and multiplexing option is need of the hour for analysis of molecular events, particularly in the current omics era. These are the area where NPs can come handy against conventional methods of separation. Utility of SiO2/Fe2O3 composite NPs along with AuNPs has been extensively explored for simultaneous extraction of DNA and real-time polymerase chain reaction (PCR) performance in one well. This method is very suitable for faster and efficient identification of pathogen in a given sample [250]. Similarly, DNA has been extracted from bacteria cells by using of MNPs at faster rate which can be applied for simple, low-cost, and fast screening of pathogens. Similarly, other functionalization has been employed to form carboxyl-coated MNPs to separate and

138

Handbook of Nanomaterials in Analytical Chemistry

isolate messenger RNA from mammalian cells and DNA from gel without using organic solvents or spin columns [87]. Perc¸in et al. have applied affinity chromatography using boronate NPs for extraction of RNA [88]. Various other relevant examples of application have been delineated in Table 6.2.

6.4.3 Protein and peptide separation Proteins are the end product of central dogma that needs to be separated from complex tissues for various analytical processes. Separation of protein and peptide from minute amount of samples in wholesome is important for proteomics and metabolomics study. Various properties of NPs have been explored for efficient and pure separation of these molecules from complex biological fluids or materials. MNPs are capable of isolating proteins and peptides from cell lysate or solution in femtogram level as well as with high yield for their analysis and commercial applications [55]. Phospholipid-coated colloidal MNPs have found to be effective for recovery and separation of proteins because of low resistance and high adsorptive capacities [56]. Similarly, the enrichment efficiency of phosphopeptides has also found to be enhanced when diamond or titanium dioxide NPs are used in affinity chromatographic-based separation [68,69].

6.4.4 Application in metabolite separation Analysis of metabolites is important for elucidation of various pathways and their errors which are useful for diagnostic and developmental study. However, isolation of a particular group of metabolite in efficient and economical way is challenging mostly due to their short half-life and minute sample volume. NP-based separation and enrichment techniques have prospered metabolomics study even up to cellular level. Specific targets aptamers have been used along with NPs for metabolites, such as adenosine triphosphate, theophylline, cocaine, histidine, argininamide, tyrosinamide, guanosine triphosphate, or arginine analysis by several research groups [251]. For example, fluorescence, magnetic, and dual-encoded spheres have been employed for simultaneous separation of dolichos biflorus agglutinin, peanut agglutinin, and ulex europaeus agglutinin I which are three different kinds of lecithins from a complex samples [246]. Silica NPs are widely used for separation of several metabolites. The method provides metabolite enrichment and can be used for metabolomics study since coverage and obtained signal spectra are more prominent [251]. Further application of NPs has observed to increase the analytical efficiency, such as generation of improved NMR spectra for metabolomics study, ionization enhancement in MS, or improvement of the detectors for better signal acquisition [251].

6.4.5 Application in material science Introduction of NMs in separation techniques has contributed enormously in rapid development of material science which is evident from the earlier discussion. Enantioseparation of isomeric molecules and separation of compounds for industrial applications exploiting several physicochemical properties, such as acidic/basic

Separation techniques with nanomaterials

139

properties or inorganic/organic nature, are some of the examples of nanointerventions in material science that has been discussed in earlier sections along with further detail given in Table 6.2. Application of NMs in separation science is a wide-open page in which only a few marks have been drawn and most of them are restricted to academic purpose only. Better understanding about the unique properties of the NMs will certainly augment their applications toward novel directions. Nanoscience is progressing at a rapid pace to uncover those mysteries for establishing reliability and confidence over nano-interventions in separation science and justify their potential.

6.5

Conclusions and future prospects

Separation of target molecules from a cocktail maintaining supreme purity and innate integrity is prerequisite for successful downstream analysis. Thus intervention in standard conventional separation techniques requires critical care, rather to say minimum manipulation is desirable. But the traditional separation methods are continuously getting stressed from emerging expectations arising from the rapid development in downstream analytical techniques. As an example, recent omics technique deals with minute sample volume, thus parallel separation platform must have to operate in such deprivation and necessarily separation efficiency as well as detection sensitivity has to be increased significantly. Similarly, simultaneous analysis of multiple samples within a short duration requires high throughput and multiplexing option. So, nano-intervention in conventional separation techniques has become inevitable. Several promising results in various separation platforms using different types of NMs have generated considerable interest in recent times which is receiving further stimuli from rapid developments in nanotechnology aspect. However, repeatability of analysis is the major obstacle for wide industrial applications of NMs in various separation methods, thus limiting their utility mostly to academic interest. Nanotechnology has already made significant contribution in biomedical and pharmaceutical industry recovering from their limitations in the respective fields. Rigorous efforts are also going on to eliminate the issues of NPs for their industrial application in separation science. Significant progress has been made toward uniform NP synthesis and their characterization process which will certainly assist for better understanding of their interaction properties to customize efficient, sensitive, and reproducible separation methods involving nano-interventions. Thus even considerable substitution of the components of traditional separation methods with novel nano-formulations is not beyond the scope in the near future.

References [1] P.K. Mukherjee, Nanomaterials: materials with immense potential, J. Appl. Chem. 5 (4) (2016) 714 7181. [2] S. Tyagi, V.K. Pandey, Nanoparticles: an overview of preparation, Res. Rev.: J. Pharm. Nanotechnol. JPN 4 (2) (2016). ,http://www.rroij.com/open-access/nanoparticles-anoverview-of-preparation-.php?aid 5 82205..

140

Handbook of Nanomaterials in Analytical Chemistry

[3] M.F. Hochella Jr, A.S. Madden, Earth’s nano-compartment for toxic metals, Elements 1 (2005) 199 203. Available from: https://doi.org/10.2113/gselements.1.4.199. [4] J.N. Tiwari, R.N. Tiwari, K.S. Kim, Zero-dimensional, one-dimensional, twodimensional and three-dimensional nanostructured materials for advanced electrochemical energy devices, Prog. Mater. Sci. 57 (4) (2012) 724 803. Available from: https:// doi.org/10.1016/j.pmatsci.2011.08.003. [5] C.P. Bergmann, F. Machado, Carbon nanomaterials as adsorbents for environmental and biological applications, in: Carbon Nanostructures (Paulo Araujo, Tuscaloosa, AL, USA), Library of Congress, Springer Cham Heidelberg, New York, Dordrecht, London, Springer International Publishing, Switzerland, 2015, pp. 1 126, ,https://doi.org/ 10.1007/978-3-319-18875-1.. [6] X. Ren, J. Li, X. Tan, X. Wang, Comparative study of graphene oxide, activated carbon and carbon nanotubes as adsorbents for copper decontamination, Dalton Trans. 42 (2013) 5266 5274. Available from: https://doi.org/10.1039/c3dt32969k. [7] D. Wang, H. Shakeel, J. Lovette, G.W. Rice, J.R. Heflin, M. Agah, Highly stable surface functionalization of microgas chromatography columns using layer-bylayer self-assembly of silica nanoparticles, Anal. Chem. 85 (17) (2013) 8135 8141. Available from: https://doi.org/10.1021/ac401080u. [8] V.K. Gupta, T.A. Saleh, Sorption of pollutants by porous carbon, carbon nanotubes and fullerene—an overview, Environ. Sci. Pollut. Res. 20 (2013) 2828 2843. Available from: https://doi.org/10.1007/s11356-013-1524-1. [9] H.W. Kroto, J.R. Heath, S.C. O’Brien, R.F. Curl, R.E. Smalley, C60: buckminsterfullerene, Nature 318 (1985) 162 163. [10] L.A. Kartsova, A.A. Makarov, New fullerene-based stationary phases for gas chromatography, J. Anal. Chem. 59 (2004) (2004) 724 729. [11] A. Astefanei, O. Nu´n˜ez, M.T. Galceran, Characterisation and determination of fullerenes: a critical review, Anal. Chim. Acta 882 (2015) 1 21. Available from: https://doi. org/10.1016/j.aca.2015.03.025. [12] A. Speltini, D. Merli, A. Profumo, Analytical application of carbon nanotubes, fullerenes and nanodiamonds in nanomaterials-based chromatographic stationary phases: a review, Anal. Chim. Acta 783 (2013) 1 16. Available from: https://doi.org/10.1016/j. aca.2013.03.041. [13] M. Zhang, H. Qiu, Progress in stationary phases modified with carbonaceous nanomaterials for high-performance liquid chromatography, TrAC, Trends Anal. Chem. 65 (2015) 107 121. [14] S. Iijima, Helical microtubules of graphitic carbon, Nature 354 (6348) (1991) 56 58. Available from: https://doi.org/10.1038/354056a0. [15] D. Merli, A. Profumo, D. Dondi, A. Albini, Photoelectrochemical studies of gold electrodes chemically modified with single-walled carbon nanotubes, Chem. Phys. Chem. 10 (7) (2009) 1090 1096. Available from: https://doi.org/10.1002/cphc.200800684. ´ . Rodrı´guez[16] L.M. Ravelo-Pe´rez, A.V. Herrera-Herrera, J. Herna´ndez-Borges, M.A Delgado, Carbon nanotubes: solid-phase extraction, J. Chromatogr. A 1217 (16) (2010) 2618 2641. Available from: https://doi.org/10.1016/j.chroma.2009.10.083. [17] X. Ren, C. Chen, M. Nagatsu, X. Wang, Carbon nanotubes as adsorbents in environmental pollution management: a review, Biochem. Eng. J. 170 (2 3) (2011) 395 410. Available from: https://doi.org/10.1016/j.cej.2010.08.045. [18] M. Trojanowicz, Analytical applications of carbon nanotubes: a review TrAC, Trends Anal. Chem. 25 (5) (2006) 480 489. Available from: https://doi.org/10.1016/j. trac.2005.11.008.

Separation techniques with nanomaterials

141

[19] C. Andre´, R. Aljhani, T. Gharbi, Y.C. Guillaume, Incorporation of carbon nanotubes in a silica HPLC column to enhance the chromatographic separation of peptides: theoretical and practical aspects, J. Sep. Sci. 34 (11) (2011) 1221 1227. Available from: https://doi.org/10.1002/jssc.201000903. [20] C. Andre´, R. Aljhni, L. Lethier, Y.C. Guillaume, Carbon nanotube poroshell silica as a novel stationary phase for fast HPLC analysis of monoclonal antibodies, Anal. Bioanal. Chem. 406 (3) (2013) 905 909. Available from: https://doi.org/10.1007/s00216-0137532-7. [21] X. Fang, S.V. Olesik, Carbon nanotube and carbon nanorod-filled polyacrylonitrile electrospun stationary phase for ultrathin layer chromatography, Anal. Chim. Acta 830 (2014) 1 10. Available from: https://doi.org/10.1016/j.aca.2014.04.011. [22] Z. Huang, L. Xi, Q. Subhani, W. Yan, W. Guo, Y. Zhu, Covalent functionalization of multi-walled carbon nanotubes with quaternary ammonium groups and its application in ion chromatography, Carbon 62 (2013) 127 134. Available from: https://doi.org/ 10.1016/j.carbon.2013.06.004. [23] X. Liang, S. Liu, H. Liu, X. Liu, S. Jiang, Layer-by-layer self-assembled multi-walled carbon nanotubes/silica microsphere composites as stationary phase for highperformance liquid chromatography, J. Sep. Sci. 33 (21) (2010) 3304 3312. Available from: https://doi.org/10.1002/jssc.201000379. [24] E. Mayadunne, Z. El Rassi, Facile preparation of octadecyl monoliths with incorporated carbon nanotubes and neutral monoliths with coated carbon nanotubes stationary phases for HPLC of small and large molecules by hydrophobic and π π interactions, Talanta 129 (2014) 565 574. Available from: https://doi.org/10.1016/j.talanta.2014.06.032 (24). [25] E.P. Nesterenko, P.N. Nesterenko, D. Connolly, X. He, P. Floris, E. Duffy, et al., Nano-particle modified stationary phases for high-performance liquid chromatography, Analyst 138 (15) (2013) 4229. Available from: https://doi.org/10.1039/c3an00508a. [26] P.N. Nesterenko, O.N. Fedyanina, Y.V. Volgin, Microdispersed sintered nanodiamonds as a new stationary phase for high-performance liquid chromatography, Analyst 132 (5) (2007) 403. Available from: https://doi.org/10.1039/b702272g. [27] S. Choudhury, E. Duffy, D. Connolly, B. Paull, B. White, Graphene oxide nanoparticles and their influence on chromatographic separation using polymeric high internal phase emulsions, Separations 4 (1) (2017) 5. Available from: https://doi.org/10.3390/ separations4010005. [28] X.Y. Chen, Z. Razzaz, S. Kaliaguine, D. Rodrigue, Mixed matrix membranes based on silica nanoparticles and microcellular polymers for CO2/CH4 separation, J. Cell. Plast. 54 (2) (2016) 309 331. Available from: https://doi.org/10.1177/0021955x16681453. [29] E. Hilder, F. Svec, J. Frechet, Latex-functionalized monolithic columns for the separation of carbohydrates by micro anion-exchange chromatography, J. Chromatogr. A 1053 (1 2) (2004) 101 106. Available from: https://doi.org/10.1016/s0021-9673(04) 01090-8. [30] G. Guerrero, D. Venturi, T. Peters, N. Rival, C. Denonville, C. Simon, et al., Influence of functionalized nanoparticles on the CO2/N2 separation properties of PVA-based gas separation membranes, Energy Procedia 114 (2017) 627 635. Available from: https:// doi.org/10.1016/j.egypro.2017.03.1205. [31] T. De Boer, R. Mol, R.A. de Zeeuw, G.J. de Jong, D.C. Sherrington, P.A.G. Cormack, et al., Spherical molecularly imprinted polymer particles: a promising tool for molecular recognition in capillary electrokinetic separations, Electrophoresis 23 (9) (2002) 1296 1300. ,https://doi.org/10.1002/1522-2683(200205)23:9 , 1296::aidelps1296 . 3.0.co;2-2..

142

Handbook of Nanomaterials in Analytical Chemistry

[32] P. Paik, A. Gedanken, Y. Mastai, Chiral-mesoporous-polypyrrole nanoparticles: its chiral recognition abilities and use in enantioselective separation, J. Mater. Chem. 20 (20) (2010) 4085. Available from: https://doi.org/10.1039/c000232a. [33] C. Chang, X. Wang, Y. Bai, H. Liu, Applications of nanomaterials in enantioseparation and related techniques, TrAC, Trends Anal. Chem. 39 (2012) 195 206. Available from: https://doi.org/10.1016/j.trac.2012.07.002. [34] S.R. Beeram, E. Rodriguez, S. Doddavenkatanna, Z. Li, A. Pekarek, D. Peev, et al., Nanomaterials as stationary phases and supports in liquid chromatography, Electrophoresis 38 (19) (2017) 2498 2512. Available from: https://doi.org/10.1002/elps.201700168. [35] K.K. Unger, R. Skudas, M.M. Schulte, Particle packed columns and monolithic columns in high-performance liquid chromatography-comparison and critical appraisal, J. Chromatogr. A 1184 (1 2) (2008) 393 415. Available from: https://doi.org/10.1016/j. chroma.2007.11.118. [36] J. Ahn, W.-J. Chung, I. Pinnau, M.D. Guiver, Polysulfone/Silica nanoparticle mixedmatrix membranes for gas separation, J. Membr. Sci. 314 (1 2) (2008) 123 133. Available from: https://doi.org/10.1016/j.memsci.2008.01.031. [37] Y. Hang, Y. Qin, Z. Jiang, B. Hu, Direct analysis of trace rare earth elements by fluorination assisted ETV-ICP-AES with slurry sampling through nano-sized TiO2 separation/preconcentration, Anal. Sci. 18 (7) (2002) 843 846. Available from: https://doi. org/10.2116/analsci.18.843. [38] M. Regiart, L.A. Escudero, P. Aranda, N.A. Martinez, F.A. Bertolino, J. Raba, Copper nanoparticles applied to the preconcentration and electrochemical determination of β-adrenergic agonist: an efficient tool for the control of meat production, Talanta 135 (2015) 138 144. Available from: https://doi.org/10.1016/j.talanta.2014.12.026. [39] Y. Xu, Q. Cao, F. Svec, J.M.J. Fre´chet, Porous polymer monolithic column with surface-bound gold nanoparticles for the capture and separation of cysteine-containing peptides, Anal. Chem. 82 (8) (2010) 3352 3358. Available from: https://doi.org/ 10.1021/ac1002646. [40] K. Dastafkan, M. Khajeh, M. Ghaffari-Moghaddam, M. Bohlooli, Silver nanoparticles for separation and preconcentration processes, TrAC, Trends Anal. Chem. 64 (2015) 118 126. Available from: https://doi.org/10.1016/j.trac.2014.08.017. [41] C.H. Lee, B.Y. Huang, Y.C. Chen, C.P. Liu, C.Y. Liu, Zirconia nanoparticles-coated column for the capillary electrochromatographic separation of iron-binding- and phosphorylated-proteins, Analyst 136 (7) (2011) 1481. Available from: https://doi.org/ 10.1039/c0an00900h. [42] H. Dun, W. Zhang, Y. Wei, S. Xiuqing, Y. Li, L. Chen, Layer-by-layer self-assembly of multilayer zirconia nanoparticles on silica spheres for HPLC packings, Anal. Chem. 76 (17) (2004) 5016 5023. Available from: https://doi.org/10.1021/ac030389j. [43] B. Soltani, M. Asghari, Effects of ZnO nanoparticle on the gas separation performance of polyurethane mixed matrix membrane, Membranes 7 (3) (2017) 43. Available from: https://doi.org/10.3390/membranes7030043. [44] C. Acquah, E. Obeng, D. Agyei, C. Ongkudon, C. Moy, M. Danquah, Nano-doped monolithic materials for molecular separation, Separations 4 (1) (2017) 2. Available from: https://doi.org/10.3390/separations4010002. [45] J. Tan, J. Neo, T. Setiawati, C. Zhang, Determination of carotenoids in human serum and breast milk using high performance liquid chromatography coupled with a diode array detector (HPLC-DAD), Separations 4 (2) (2017) 19. Available from: https://doi. org/10.3390/separations4020019.

Separation techniques with nanomaterials

143

[46] M.R. Gama, C.B.G. Bottoli, Nanomaterials in liquid chromatography: recent advances in stationary phases, Nanomater. Chromatogr. (2018) 255 297. Available from: https:// doi.org/10.1016/b978-0-12-812792-6.00009. [47] M. Wierucka, M. Biziuk, Application of magnetic nanoparticles for magnetic solid-phase extraction in preparing biological, environmental and food samples, TrAC, Trends Anal. Chem. 59 (2014) 50 58. Available from: https://doi.org/10.1016/j.trac.2014.04.007. [48] M.L. Castillo-Garcı´a, M.P. Aguilar-Caballos, A. Go´mez-Hens, Nanomaterials as tools in chromatographic methods, TrAC, Trends Anal. Chem. 82 (2016) 385 393. Available from: https://doi.org/10.1016/j.trac.2016.06.019. [49] C.C. Striemer, T.R. Gaborski, J.L. McGrath, P.M. Fauchet, Charge- and size-based separation of macromolecules using ultrathin silicon membranes, Nature 445 (7129) (2007) 749 753. Available from: https://doi.org/10.1038/nature05532. [50] X.Y. Qiu, H.Z. Yu, K.V. Peinemann, Selective separation of similarly sized proteins with tunable nanoporous block copolymer membranes, Procedia Eng. 44 (2012) 461 463. Available from: https://doi.org/10.1016/j.proeng.2012.08.450. [51] M. Irfan, Sulfonated Polyethersulfone and Functionalized MWCNT/PVP Nanocomposite Membrane for Protein Separation (Thesis for Doctor of Philosophy of Science), Faculty of Science, Technology and Human Development, Universiti Tun Hussein Onn Malaysia, 2017. [52] C. Schuster, A. Rodler, R. Tscheliessnig, A. Jungbauer, Freely suspended perforated polymer nanomembranes for protein separations, Sci. Rep. 8 (1) (2018). Available from: https://doi.org/10.1038/s41598-018-22200-4. [53] J. Shin, H. Kim, H. Moon, M.J. Kwak, S. Oh, Y. Yoo, et al., A hydrogel-coated membrane for highly efficient separation of microalgal bio-lipid, Korean J. Chem. Eng. 35 (6) (2018) 1319 1327. Available from: https://doi.org/10.1007/s11814-018-0039-3. [54] Y.-C. Li, Y.-S. Lin, P.-J. Tsai, C.-T. Chen, W.-Y. Chen, Y.-C. Chen, Nitrilotriacetic acid-coated magnetic nanoparticles as affinity probes for enrichment of histidinetagged proteins and phosphorylated peptides, Anal. Chem. 79 (19) (2007) 7519 7525. Available from: https://doi.org/10.1021/ac0711440. [55] P. Fraga Garcı´a, M. Brammen, M. Wolf, S. Reinlein, M. Freiherr von Roman, S. Berensmeier, High-gradient magnetic separation for technical scale protein recovery using low cost magnetic nanoparticles, Sep. Purif. Technol. 150 (2015) 29 36. Available from: https://doi.org/10.1016/j.seppur.2015.06.024. [56] S. Bucak, D.A. Jones, P.E. Laibinis, T.A. Hatton, Protein separations using colloidal magnetic nanoparticles, Biotechnol. Progr. 19 (2) (2003) 477 484. Available from: https://doi.org/10.1021/bp0200853. [57] I. Fischer, C.C. Hsu, M. G¨artner, C. Mu¨ller, T.W. Overton, O.R.T. Thomas, et al., Continuous protein purification using functionalized magnetic nanoparticles in aqueous micellar two-phase systems, J. Chromatogr. A 1305 (2013) 7 16. Available from: https://doi.org/10.1016/j.chroma.2013.06.011. [58] H. Gu, K. Xu, C. Xu, B. Xu, Biofunctional magnetic nanoparticles for protein separation and pathogen detection, Chem. Commun. 9 (2006) 941. Available from: https:// doi.org/10.1039/b514130c. [59] N. Hu, Z. Wu, L. Jin, Z. Li, W. Liu, D. Huang, et al., Nanoparticle as a novel foam controller for enhanced protein separation from sweet potato starch waste water, Sep. Purif. Technol. 209 (2019) 392 400. Available from: https://doi.org/10.1016/j. seppur.2018.07.064.

144

Handbook of Nanomaterials in Analytical Chemistry

[60] X. Ke, Y. Huang, T.R. Dargaville, Y. Fan, Z. Cui, H. Zhu, Modified alumina nanofiber membranes for protein separation, Sep. Purif. Technol. 120 (2013) 239 244. Available from: https://doi.org/10.1016/j.seppur.2013.10.011. [61] J. Krenkova, N.A. Lacher, F. Svec, Control of selectivity via nanochemistry: monolithic capillary column containing hydroxyapatite nanoparticles for separation of proteins and enrichment of phosphopeptides, Anal. Chem. 82 (19) (2010) 8335 8341. Available from: https://doi.org/10.1021/ac1018815. [62] Z. Liu, J. Liu, Z. Liu, H. Wang, J. Ou, M. Ye, et al., Functionalization of hybrid monolithic columns via thiol-ene click reaction for proteomics analysis, J. Chromatogr. A 1498 (2017) 29 36. Available from: https://doi.org/10.1016/j.chroma.2017.01.029. [63] D. Tamburro, C. Fredolini, V. Espina, T.A. Douglas, A. Ranganathan, L. Ilag, et al., Multifunctional core shell nanoparticles: discovery of previously invisible biomarkers, J. Am. Chem. Soc. 133 (47) (2011) 19178 19188. Available from: https://doi.org/ 10.1021/ja207515j. ¨. C [64] K. Salimi, D.D. Usta, O ¸ elikbıc¸ak, A. Pinar, B. Salih, A. Tuncel, Ti(IV) carrying polydopamine-coated, monodisperse-porous SiO2 microspheres with stable magnetic properties for highly selective enrichment of phosphopeptides, Colloids Surf., B: Biointerfaces 153 (2017) 280 290. Available from: https://doi.org/10.1016/j. colsurfb.2017.02.028. [65] G. Huang, Z. Sun, H. Qin, L. Zhao, Z. Xiong, X. Peng, et al., Preparation of hydrazine functionalized polymer brushes hybrid magnetic nanoparticles for highly specific enrichment of glycopeptides, Analyst 139 (9) (2014) 2199. Available from: https://doi. org/10.1039/c4an00076e. [66] S.H. Huang, M.H. Liao, D.H. Chen, Direct binding and characterization of lipase onto magnetic nanoparticles, Biotechnol. Progr. 19 (3) (2003) 1095 1100. Available from: https://doi.org/10.1021/bp025587v. [67] B.-H. Lai, C.-H. Chang, C.-C. Yeh, D.-H. Chen, Direct binding of Concanvalin A onto iron oxide nanoparticles for fast magnetic selective separation of lactoferrin, Sep. Purif. Technol. 108 (2013) 83 88. Available from: https://doi.org/10.1016/j. seppur.2013.02.020. [68] D. Hussain, M. Najam-ul-Haq, F. Jabeen, M.N. Ashiq, M. Athar, M. Rainer, et al., Functionalized diamond nanopowder for phosphopeptides enrichment from complex biological fluids, Anal. Chim. Acta 775 (2013) 75 84. Available from: https://doi.org/ 10.1016/j.aca.2013.03.007. ˇ [69] U. Cernigoj, J. Gaˇsperˇsiˇc, A. Fichtenbaum, N. LenderoKrajnc, J. Vidiˇc, G. Mitulovi´c, et al., Titanium dioxide nanoparticle coating of polymethacrylate-based chromatographic monoliths for phosphopetides enrichment, Anal. Chim. Acta 942 (2016) 146 154. Available from: https://doi.org/10.1016/j.aca.2016.08.044. [70] X.N. Wei, H.L. Wang, Facile fabrication of hydrophilic PAA-Ti/TiO2 nanocomposite for selective enrichment and detection of phosphopeptides from complex biological samples, Anal. Chim. Acta 949 (2017) 67 75. Available from: https://doi.org/10.1016/ j.aca.2016.10.036. [71] D. Li, H. Xia, L. Wang, Branched polyethyleneimine-assisted boronic acidfunctionalized silica nanoparticles for the selective enrichment of trace glycoproteins, Talanta 184 (2018) 235 243. Available from: https://doi.org/10.1016/j. talanta.2018.02.021. [72] D. Li, Z. Bie, Branched polyethyleneimine-assisted boronic acid-functionalized magnetic nanoparticles for the selective enrichment of trace glycoproteins, Analyst 142 (23) (2017) 4494 4502. Available from: https://doi.org/10.1039/c7an01174a.

Separation techniques with nanomaterials

145

[73] Y.A. Elfimova, D.A. Pichugina, I.A. Anan’eva, A.G. Mazhuga, O.A. Shpigun, Zh. Fiz. Khim. 86 (10) (2012) 1739 1746. [74] Y. Yao, J. Dong, M. Dong, F. Liu, Y. Wang, J. Mao, et al., An immobilized titanium (IV) ion affinity chromatography adsorbent for solid phase extraction of phosphopeptides for phosphoproteome analysis, J. Chromatogr. A 1498 (2017) 22 28. Available from: https://doi.org/10.1016/j.chroma.2017.03.026. [75] J.L. Chen, T.L. Lu, Y.C. Lin, Multi-walled carbon nanotube composites with polyacrylate prepared for open-tubular capillary electrochromatography, Electrophoresis 31 (19) (2010) 3217 3226. Available from: https://doi.org/10.1002/elps.201000226. [76] C. Andre´, T. Gharbi, Y.-C. Guillaume, A novel stationary phase based on amino derivatized nanotubes for HPLC separations: theoretical and practical aspects, J. Sep. Sci. 32 (10) (2009) 1757 1764. Available from: https://doi.org/10.1002/jssc.200800683. [77] S. Currivan, D. Connolly, B. Paull, Production of polymer monolithic capillary columns with integrated gold nano-particle modified segments for on-capillary extraction, Microchem. J. 111 (2013) 32 39. Available from: https://doi.org/10.1016/j. microc.2012.08.007. [78] R. Wu, X. Ou, R. Tian, J. Zhang, H. Jin, M. Dong, et al., Membrane destruction and phospholipids extraction by two dimensional MoS2 nanosheets, Nanoscale (2018). Available from: https://doi.org/10.1039/c8nr04207a. [79] Y.K. Lee, H. Lee, J.-M. Nam, Lipid-nanostructure hybrids and their applications in nanobiotechnology, NPG Asia Mater. 5 (5) (2013) e48. Available from: https://doi.org/ 10.1038/am.2013.13. [80] L. Gu, Y. Wang, J. Han, L. Wang, X. Tang, C. Li, et al., Phenylboronic acidfunctionalized core shell magnetic composite nanoparticles as a novel protocol for selective enrichment of fructose from a fructose glucose aqueous solution, New J. Chem. 41 (22) (2017) 13399 13407. Available from: https://doi.org/10.1039/ c7nj02106b. [81] Q. Shen, W. Dong, M. Yang, J.T. Baibado, Y. Wang, I. Alqouqa, et al., Lipidomic study of olive fruit and oil using TiO2 nanoparticle based matrix solid-phase dispersion and MALDI-TOF/MS, Food Res. Int. 54 (2) (2013) 2054 2061. Available from: https://doi.org/10.1016/j.foodres.2013.10.001. [82] M. Rainer, M.N. Qureshi, G.K. Bonn, Matrix-free and material-enhanced laser desorption/ionization mass spectrometry for the analysis of low molecular weight compounds, Anal. Bioanal. Chem. 400 (8) (2010) 2281 2288. Available from: https://doi.org/ 10.1007/s00216-010-4138-1. [83] X. Wei, Z. Liu, X. Jin, L. Huang, D.D. Gurav, X. Sun, et al., Plasmonicnanoshells enhanced laser desorption/ionization mass spectrometry for detection of serum metabolites, Anal. Chim. Acta 950 (2017) 147 155. Available from: https://doi.org/10.1016/j. aca.2016.11.017. [84] L.-M. Li, F. Yang, H.-F. Wang, X.-P. Yan, Metal-organic framework polymethyl methacrylate composites for open-tubular capillary electrochromatography, J. Chromatogr. A 1316 (2013) 97 103. Available from: https://doi.org/10.1016/j.chroma.2013.09.081. [85] B. Zhang, M. Xie, L. Bruschweiler-Li, K. Bingol, R. Bru¨schweiler, Use of charged nanoparticles in NMR-based metabolomics for spectral simplification and improved metabolite identification, Anal. Chem. 87 (14) (2015) 7211 7217. Available from: https://doi.org/10.1021/acs.analchem.5b01142 (37). [86] A. Sebastianelli, T. Sen, I.J. Bruce, Extraction of DNA from soil using nanoparticles by magnetic bioseparation, Lett. Appl. Microbiol. 46 (4) (2008) 488 491. Available from: https://doi.org/10.1111/j.1472-765x.2008.02343.x.

146

Handbook of Nanomaterials in Analytical Chemistry

[87] T.R. Sarkar, J. Irudayaraj, Carboxyl-coated magnetic nanoparticles for mRNA isolation and extraction of supercoiled plasmid DNA, Anal. Biochem. 379 (1) (2008) 130 132. Available from: https://doi.org/10.1016/j.ab.2008.04.016. [88] I. Perc¸in, N. ˙Idil, A. Denizli, RNA purification from Escherichia coli cells using boronated nanoparticles, Colloids Surf., B: Biointerfaces 162 (2018) 146 153. Available from: https://doi.org/10.1016/j.colsurfb.2017.11.044. [89] P. Oberacker, P. Stepper, D.M. Bond, S. Ho¨hn, J. Focken, V. Meyer, et al., Bio-OnMagnetic-Beads (BOMB): open platform for high-throughput nucleic acid extraction and manipulation, PLoS Biol. 17 (2019) e3000107. Available from: https://doi.org/ 10.1101/414516. [90] J. Wang, Z. Ali, N. Wang, W. Liang, H. Liu, F. Li, et al., Simultaneous extraction of DNA and RNA from Escherichia coli BL 21 based on silica-coated magnetic nanoparticles, Sci. China Chem. 58 (11) (2015) 1774 1778. Available from: https://doi.org/ 10.1007/s11426-015-5483-x. [91] K. Niemirowicz, Z. Agnieszka, A. Wilczewsk, C.A.R. Halina, Magnetic nanoparticles as separators of nucleic acids, Chemik 67 (10) (2013) 836 841. ¨ zek, L. Uzun, S. Senel, [92] R. U ¸ A. Denizli, Nanospines incorporation into the structure of the hydrophobic cryogels via novel cryogelation method: an alternative sorbent for plasmid DNA purification, Colloids Surf., B: Biointerfaces 102 (2013) 243 250. Available from: https://doi.org/10.1016/j.colsurfb.2012.08.020. [93] Z. Li, C. Liu, Y. Yamaguchi, Y. Ni, Q. You, X. Dou, Capillary electrophoresis of a wide range of DNA fragments in a mixed solution of hydroxyethyl cellulose, Anal. Methods 6 (8) (2014) 2473 2477. Available from: https://doi.org/10.1039/ c3ay41965g. [94] C.M. Ongkudon, M.K. Danquah, Anion exchange chromatography of 4.2kbp plasmid based vaccine (pcDNA3F) from alkaline lysed E. coli lysate using amino functionalised polymethacrylate conical monolith, Sep. Purif. Technol. 78 (3) (2011) 303 310. Available from: https://doi.org/10.1016/j.seppur.2011.01.039. [95] M.K. Sinha, M.K. Purkait, Use of CS PAA nanoparticles as an alternative to metal oxide nanoparticles and their effect on fouling mitigation of a PSF ultrafiltration membrane, RSC Adv. 5 (81) (2015) 66109 66121. Available from: https://doi.org/ 10.1039/c5ra08743k. [96] W. Yu, L. Xu, N. Graham, J. Qu, Contribution of Fe3O4 nanoparticles to the fouling of ultrafiltration with coagulation pre-treatment, Sci. Rep. 5 (1) (2015). Available from: https://doi.org/10.1038/srep13067. [97] V. Subramaniam, L. Griffith, A.J. Haes, Varying nanoparticle pseudostationary phase plug length during capillary electrophoresis, Analyst 136 (17) (2011) 3469. Available from: https://doi.org/10.1039/c1an15185a. [98] L.P. Duan, G.S. Ding, A.N. Tang, Preparation of chitosan-modified silica nanoparticles and their applications in the separation of auxins by capillary electrophoresis, J. Sep. Sci. 38 (22) (2015) 3976 3982. Available from: https://doi.org/10.1002/ jssc.201500810. [99] H. Li, Y. Shan, L. Qiao, A. Dou, X. Shi, G. Xu, Facile synthesis of boronatedecorated polyethyleneimine-grafted hybrid magnetic nanoparticles for the highly selective enrichment of modified nucleosides and ribosylated metabolites, Anal. Chem. 85 (23) (2013) 11585 11592. Available from: https://doi.org/10.1021/ ac402979w.

Separation techniques with nanomaterials

147

[100] C. Pan, W. Wang, H. Zhang, L. Xu, X. Chen, In situ synthesis of homochiral metal organic framework in capillary column for capillary electrochromatography enantioseparation, J. Chromatogr. A 1388 (2015) 207 216. Available from: https:// doi.org/10.1016/j.chroma.2015.02.034. [101] G.S. Chirica, V.T. Remcho, Fritless capillary columns for HPLC and CEC prepared by immobilizing the stationary phase in an organic polymer matrix, Anal. Chem. 72 (15) (2000) 3605 3610. Available from: https://doi.org/10.1021/ac000179w. [102] C. Yu, M. Xu, F. Svec, J.M.J. Fre´chet, Preparation of monolithic polymers with controlled porous properties for microfluidic chip applications using photoinitiated freeradical polymerization, J. Polym. Sci., A: Polym. Chem. 40 (6) (2002) 755 769. Available from: https://doi.org/10.1002/pola.10155. [103] K. Salimi, D.D. Usta, ˙I. Koc¸er, E. C¸elik, A. Tuncel, Protein A and protein A/G coupled magnetic SiO2 microspheres for affinity purification of immunoglobulin G, Int. J. Biol. Macromol. 111 (2018) 178 185. Available from: https://doi.org/10.1016/j. ijbiomac.2018.01.019. [104] M. Amoli-Diva, K. Pourghazi, Gold nanoparticles grafted modified silica gel as a new stationary phase for separation and determination of steroid hormones by thin layer chromatography, J. Food Drug Anal. 23 (2) (2015) 279 286. Available from: https:// doi.org/10.1016/j.jfda.2014.11.005. [105] G. Feng, D. Hu, L. Yang, Y. Cui, X. Cui, H. Li, Immobilized-metal affinity chromatography adsorbent with paramagnetism and its application in purification of histidine-tagged proteins, Sep. Purif. Technol. 74 (2) (2010) 253 260. Available from: https://doi.org/10.1016/j.seppur.2010.06.013. [106] J.M. Cintro´n, L.A. Colo´n, Organo-silica nano-particles used in ultrahigh-pressure liquid chromatography, Analyst 127 (6) (2002) 701 704. Available from: https://doi. org/10.1039/b203236h. [107] F.-J. Liu, G.-S. Ding, A.-N. Tang, Simultaneous separation and determination of five organic acids in beverages and fruits by capillary electrophoresis using diamino moiety functionalized silica nanoparticles as pseudostationary phase, Food Chem. 145 (2014) 109 114. Available from: https://doi.org/10.1016/j.foodchem.2013.08.035. [108] S. Dahane, M.D. Gil Garcı´a, A. Ucle´s Moreno, M. Martı´nez Galera, M. del Mar Socı´as Viciana, A. Derdour, Determination of eight pesticides of varying polarity in surface waters using solid phase extraction with multiwalled carbon nanotubes and liquid chromatography-linear ion trap mass spectrometry, Microchim. Acta 182 (1 2) (2014) 95 103. Available from: https://doi.org/10.1007/s00604-014-1290-x. [109] L. Wang, X. Zang, Q. Chang, C. Wang, Z. Wang, A graphene-coated magnetic nanocomposite for the enrichment of fourteen pesticides in tomato and rape samples prior to their determination by gas chromatography-mass spectrometry, Anal. Methods 6 (1) (2014) 253 260. Available from: https://doi.org/10.1039/c3ay41454j. [110] M. Zare, Z. Ramezani, N. Rahbar, Development of zirconia nanoparticles-decorated calcium alginate hydrogel fibers for extraction of organophosphorous pesticides from water and juice samples: facile synthesis and application with elimination of matrix effects, J. Chromatogr. A 1473 (2016) 28 37. Available from: https://doi.org/ 10.1016/j.chroma.2016.10.071. [111] G. Lasarte-Aragone´s, R. Lucena, S. Ca´rdenas, M. Valca´rcel, Effervescence-assisted carbon nanotubes dispersion for the micro-solid-phase extraction of triazine herbicides from environmental waters, Anal. Bioanal. Chem. 405 (10) (2013) 3269 3277. Available from: https://doi.org/10.1007/s00216-013-6718-3.

148

Handbook of Nanomaterials in Analytical Chemistry

[112] Z. He, P. Wang, D. Liu, Z. Zhou, Hydrophilic lipophilic balanced magnetic nanoparticles: preparation and application in magnetic solid-phase extraction of organochlorine pesticides and triazine herbicides in environmental water samples, Talanta 127 (2014) 1 8. Available from: https://doi.org/10.1016/j. talanta.2014.03.074. [113] F. Qiao, K.H. Row, M. Wang, Water-compatible magnetic imprinted microspheres for rapid separation and determination of triazine herbicides in environmental water, J. Chromatogr. B 957 (2014) 84 89. Available from: https://doi.org/10.1016/j. jchromb.2014.02.041. [114] M. Sajid, C. Basheer, M. Mansha, Membrane protected micro-solid-phase extraction of organochlorine pesticides in milk samples using zinc oxide incorporated carbon foam as sorbent, J. Chromatogr. A 1475 (2016) 110 115. Available from: https://doi. org/10.1016/j.chroma.2016.11.008. [115] A. Mehdinia, S. Einollahi, A. Jabbari, Magnetite nanoparticles surface-modified with a zinc(II)-carboxylate Schiff base ligand as a sorbent for solid-phase extraction of organochlorine pesticides from seawater, Microchim. Acta 183 (9) (2016) 2615 2622. Available from: https://doi.org/10.1007/s00604-016-1894-4. [116] Z. Xiong, L. Zhang, R. Zhang, Y. Zhang, J. Chen, W. Zhang, Solid-phase extraction based on magnetic core-shell silica nanoparticles coupled with gas chromatographymass spectrometry for the determination of low concentration pesticides in aqueous samples, J. Sep. Sci. 35 (18) (2012) 2430 2437. Available from: https://doi.org/ 10.1002/jssc.201200260. [117] G. Yang, Z. He, X. Liu, C. Liu, J. Zhan, D. Liu, et al., Polymer-coated magnetic nanospheres for preconcentration of organochlorine and pyrethroid pesticides prior to their determination by gas chromatography with electron capture detection, Microchim. Acta 183 (3) (2016) 1187 1194. Available from: https://doi.org/10.1007/s00604-0151725-z. [118] G. Ma, L. Chen, Development of magnetic molecularly imprinted polymers based on carbon nanotubes application for trace analysis of pyrethroids in fruit matrices, J. Chromatogr. A 1329 (2014) 1 9. Available from: https://doi.org/10.1016/j. chroma.2013.12.079. [119] F.J. Liu, C.T. Liu, W. Li, A.N. Tang, Dispersive solid-phase microextraction and capillary electrophoresis separation of food colorants in beverages using diamino moiety functionalized silica nanoparticles as both extractant and pseudostationary phase, Talanta 132 (2015) 366 372. Available from: https://doi.org/10.1016/j. talanta.2014.09.014. [120] L. Gao, L. Chen, X. Li, Magnetic molecularly imprinted polymers based on carbon nanotubes for extraction of carbamates, Microchim. Acta 182 (3 4) (2014) 781 787. Available from: https://doi.org/10.1007/s00604-014-1388-1. [121] Q. Zhou, Z. Fang, Graphene-modified TiO2 nanotube arrays as an adsorbent in microsolid phase extraction for determination of carbamate pesticides in water samples, Anal. Chim. Acta 869 (2015) 43 49. Available from: https://doi.org/10.1016/j. aca.2015.02.019. [122] Z. Wang, X. Zhang, S. Jiang, X. Guo, Magnetic solid-phase extraction based on magnetic multiwalled carbon nanotubes for the simultaneous enantiomeric analysis of five β-blockers in the environmental samples by chiral liquid chromatography coupled with tandem mass spectrometry, Talanta 180 (2018) 98 107. Available from: https:// doi.org/10.1016/j.talanta.2017.12.034.

Separation techniques with nanomaterials

149

ˇ ´nsky´, [123] M. Ha´kova´, H. Raabova´, L.C. Havlı´kova´, P. Chocholouˇs, J. Chvojka, D. Satı Testing of nylon 6 nanofibers with different surface densities as sorbents for solid phase extraction and their selectivity comparison with commercial sorbent, Talanta 181 (2018) 326 332. Available from: https://doi.org/10.1016/j.talanta.2018.01.043. [124] C. Hu, J. Deng, Y. Zhao, L. Xia, K. Huang, S. Ju, et al., A novel core shell magnetic nano-sorbent with surface molecularly imprinted polymer coating for the selective solid phase extraction of dimetridazole, Food Chem. 158 (2014) 366 373. Available from: https://doi.org/10.1016/j.foodchem.2014.02.143. [125] Q. Zeng, Y.-M. Liu, Y.-W. Jia, L.-H. Wan, X. Liao, PEGylation of magnetic multiwalled carbon nanotubes for enhanced selectivity of dispersive solid phase extraction, Mater. Sci. Eng. C 71 (2017) 186 194. Available from: https://doi.org/10.1016/j. msec.2016.09.082. [126] H. Liu, Y. Guo, X. Wang, X. Liang, X. Liu, S. Jiang, A novel fullerene oxide functionalized silica composite as stationary phase for high performance liquid chromatography, RSC Adv. 4 (34) (2014) 17541 17548. Available from: https://doi.org/10.1039/ c4ra01408a. [127] X. Liu, C. Wang, Q. Wu, Z. Wang, Magnetic porous carbon-based solid-phase extraction of carbamates prior to HPLC analysis, Microchim. Acta 183 (1) (2015) 415 421. [128] J. Cao, P. Li, L. Yi, Ionic liquids coated multi-walled carbon nanotubes as a novel pseudostationary phase in electrokinetic chromatography, J. Chromatogr. A 1218 (52) (2011) 9428 9434. Available from: https://doi.org/10.1016/j.chroma.2011.11.013. [129] J. Cao, W. Dun, H. Qu, Evaluation of the addition of various surfactant-suspended carbon nanotubes in MEEKC with an in situ-synthesized surfactant system, Electrophoresis 32 (3 4) (2011) 408 413. Available from: https://doi.org/10.1002/elps.201000535. [130] H. Shakeel, G.W. Rice, M. Agah, Semipacked columns with atomic layer-deposited alumina as a stationary phase, Sens. Actuators, B: Chem. 203 (2014) 641 646. Available from: https://doi.org/10.1016/j.snb.2014.06.017. [131] K.A. Faneer, R. Rohani, A.W. Mohammad, Polyethersulfone nanofiltration membrane incorporated with silicon dioxide prepared by phase inversion method for xylitol purification, Polym. Polym. Compos. 24 (9) (2016) 803 808. [132] H. Siddique, L.G. Peeva, K. Stoikos, G. Pasparakis, M. Vamvakaki, A.G. Livingston, Membranes for organic solvent nanofiltration based on preassembled nanoparticles, Ind. Eng. Chem. Res. 52 (3) (2012) 1109 1121. Available from: https://doi.org/ 10.1021/ie202999b. [133] Y. Wang, S. Wang, H. Niu, Y. Ma, T. Zeng, Y. Cai, et al., Preparation of polydopamine coated Fe3O4 nanoparticles and their application for enrichment of polycyclic aromatic hydrocarbons from environmental water samples, J. Chromatogr. A 1283 (2013) 20 26. Available from: https://doi.org/10.1016/j.chroma.2013.01.110. [134] X. Zhang, S. Xie, M.C. Paau, B. Zheng, H. Yuan, D. Xiao, et al., Ultrahigh performance liquid chromatographic analysis and magnetic preconcentration of polycyclic aromatic hydrocarbons by Fe3O4-doped polymeric nanoparticles, J. Chromatogr. A 1247 (2012) 1 9. Available from: https://doi.org/10.1016/j.chroma.2012.05.047. [135] M. Rezvani-Eivari, A. Amiri, M. Baghayeri, F. Ghaemi, Magnetized graphene layers synthesized on the carbon nanofibers as novel adsorbent for the extraction of polycyclic aromatic hydrocarbons from environmental water samples, J. Chromatogr. A 1465 (2016) 1 8. Available from: https://doi.org/10.1016/j.chroma.2016.08.034. [136] S. Wang, H. Sun, H.M. Ang, M.O. Tade´, Adsorptive remediation of environmental pollutants using novel graphene-based nanomaterials, Rev. Chem. Eng. J. 226 (2013) 336 347. Available from: https://doi.org/10.1016/j.cej.2013.04.070.

150

Handbook of Nanomaterials in Analytical Chemistry

[137] S.-H. Huo, X.-P. Yan, Facile magnetization of metal organic framework MIL-101 for magnetic solid-phase extraction of polycyclic aromatic hydrocarbons in environmental water samples, Analyst 137 (15) (2012) 3445. Available from: https://doi.org/ 10.1039/c2an35429b. [138] A. Amiri, M. Baghayeri, E. Hamidi, Poly(pyrrole-co-aniline)@graphene oxide/Fe3O4 sorbent for the extraction and preconcentration of polycyclic aromatic hydrocarbons from water samples, New J. Chem. (2018). Available from: https://doi.org/10.1039/ c8nj03936d. [139] H. Li, G.S. Ding, J. Chen, A.N. Tang, Amphiphilic silica nanoparticles as pseudostationary phase for capillary electrophoresis separation, J. Chromatogr. A 1217 (47) (2010) 7448 7454. Available from: https://doi.org/10.1016/j. chroma.2010.09.050. [140] X.-J. Zhou, L.-S. Zhang, W.-F. Song, Y.-P. Huang, Z.-S. Liu, A polymer monolith incorporating stellate mesoporous silica nanospheres for use in capillary electrochromatography and solid phase microextraction of polycyclic aromatic hydrocarbons and organic small molecules, Microchim. Acta 185 (9) (2018). Available from: https://doi. org/10.1007/s00604-018-2964-6. [141] Q. Qu, S. Peng, D. Mangelings, X. Hu, C. Yan, Silica spheres coated with C18modified gold nanoparticles for capillary LC and pressurized CEC separations, Electrophoresis 31 (3) (2010) 556 562. Available from: https://doi.org/10.1002/ elps.200900375. [142] F.G. Ye, J.Y. Lu, Y. Wang, A.Z. Zhang, J.N. Tian, S.L. Zhao, Preparation and characterization of gold nanoparticle-modified silica monolith for capillary electrochromatography, Chin. J. Anal. Chem. 39 (3) (2011) 341 345. Available from: https://doi.org/ 10.1016/s1872-2040(10)60430-6. [143] J. Lu, F. Ye, A. Zhang, X. Chen, Y. Wei, S. Zhao, Preparation and evaluation of ionic liquid-gold nanoparticles functionalized silica monolithic column for capillary electrochromatography, Analyst 137 (24) (2012) 5860. Available from: https://doi.org/ 10.1039/c2an35923e. [144] Y. Xu, X. Niu, Y. Dong, H. Zhang, X. Li, H. Chen, et al., Preparation and characterization of open-tubular capillary column modified with graphene oxide nanosheets for the separation of small organic molecules, J. Chromatogr. A 1284 (2013) 180 187. Available from: https://doi.org/10.1016/j.chroma.2013.01.105. [145] W. Lei, L.Y. Zhang, L. Wan, B.F. Shi, Y.Q. Wang, W.B. Zhang, Hybrid monolithic columns with nanoparticles incorporated for capillary electrochromatography, J. Chromatogr. A 1239 (2012) 64 71. Available from: https://doi.org/10.1016/j. chroma.2012.03.065. [146] H.Y. Huang, C.L. Lin, C.Y. Wu, Y.J. Cheng, C.H. Lin, Metal organic framework organic polymer monolith stationary phases for capillary electrochromatography and nano-liquid chromatography, Anal. Chim. Acta 779 (2013) 96 103. Available from: https://doi.org/10.1016/j.aca.2013.03.071. [147] X. Diao, F. Zhang, B. Yang, X. Liang, Y. Ke, X. Chu, Preparation and evaluation of C10-cationic latex particle coated open-tubular column for capillary electrochromatography, J. Chromatogr. A 1267 (2012) 127 130. Available from: https://doi.org/ 10.1016/j.chroma.2012.10.044. [148] X. Zhang, S. Chen, Q. Han, M. Ding, Preparation and retention mechanism study of graphene and graphene oxide bonded silica microspheres as stationary phases for high performance liquid chromatography, J. Chromatogr. A 1307 (2013) 135 143. Available from: https://doi.org/10.1016/j.chroma.2013.07.106.

Separation techniques with nanomaterials

151

[149] P.F. Fang, Z.R. Zeng, J.H. Fan, Y.Y. Chen, Synthesis and characteristics of fullerene polysiloxane stationary phase for capillary gas chromatography, J. Chromatogr. A 867 (1 2) (2000) 177 185. Available from: https://doi.org/10.1016/s0021-9673(99) 01143-7. [150] Q.S. Qu, X.X. Zhang, Z.Z. Zhao, X.Y. Hu, C. Yan, Gold microspheres modified with octadecanethiol for capillary liquid chromatography, J. Chromatogr. A 1198 1199 (2008) 95 100. Available from: https://doi.org/10.1016/j.chroma.2008.05.036. [151] X. Yang, C. Li, M. Qi, L. Qu, A graphene-based porous carbon material as a stationary phase for gas chromatographic separations, RSC Adv. 7 (51) (2017) 32126 32132. Available from: https://doi.org/10.1039/c7ra04774f. [152] J.R. McGettrick, N.H. Williamson, A.T. Sutton, C.P. Palmer, Performance and selectivity of cationic nanoparticle pseudo-stationary phases in electrokinetic chromatography, Electrophoresis 38 (5) (2016) 730 737. Available from: https://doi.org/10.1002/ elps.201600380. [153] S.D. Chambers, F. Svec, J.M.J. Fre´chet, Incorporation of carbon nanotubes in porous polymer monolithic capillary columns to enhance the chromatographic separation of small molecules, J. Chromatogr. A 1218 (18) (2011) 2546 2552. Available from: https://doi.org/10.1016/j.chroma.2011.02.055. [154] C. Andre´, G. Lenancker, Y.C. Guillaume, Non-covalent functionalisation of monolithic silica for the development of carbon nanotube HPLC stationary phases, Talanta 99 (2012) 580 585. Available from: https://doi.org/10.1016/j.talanta.2012.06.038. [155] X. Wang, X. Lin, Z. Xie, Preparation and evaluation of a sulfoalkylbetaine-based zwitterionic monolithic column for CEC of polar analytes, Electrophoresis 30 (15) (2009) 2702 2710. Available from: https://doi.org/10.1002/elps.200900006. [156] Z. Jiang, N.W. Smith, P.D. Ferguson, M.R. Taylor, Hydrophilic interaction chromatography using methacrylate-based monolithic capillary column for the separation of polar analytes, Anal. Chem. 79 (3) (2007) 1243 1250. Available from: https://doi. org/10.1021/ac061871f. [157] C.Y. Shi, C.H. Deng, Recent advances in inorganic materials for LDI-MS analysis of small molecules, Analyst 141 (10) (2016) 2816 2826. Available from: https://doi.org/ 10.1039/c6an00220j. [158] W. Bragg, S.A. Shamsi, A novel positively charged achiral co-monomer for β-cyclodextrin monolithicstationary phase: improved chiral separation of acidic compounds using capillary electrochromatography coupled to mass spectrometry, J. Chromatogr. A 1267 (2012) 144 155. Available from: https://doi.org/10.1016/j. chroma.2012.08.002. [159] S. Mukdasai, N. Butwong, C. Thomas, S. Srijaranai, S. Srijaranai, A sensitive and selective spectrophotometric method for 2-chlorophenol based on solid phase extraction with mixed hemimicelle magnetic nanoparticles, Arabian J. Chem. 9 (3) (2016) 463 470. Available from: https://doi.org/10.1016/j.arabjc.2014.12.023. [160] A.M. Devasurendra, D.S.W. Palagama, A. Rohanifar, D. Isailovic, J.R. Kirchhoff, J.L. Anderson, Solid-phase extraction, quantification, and selective determination of microcystins in water with a gold-polypyrrole nanocomposite sorbent material, J. Chromatogr. A 1560 (2018) 1 9. Available from: https://doi.org/10.1016/j.chroma.2018.04.027. [161] J. Chen, S. Cao, M. Zhu, C. Xi, L. Zhang, X. Li, et al., Fabrication of a high selectivity magnetic solid phase extraction adsorbent based on β-cyclodextrin and application for recognition of plant growth regulators, J. Chromatogr. A 1547 (2018) 1 13. Available from: https://doi.org/10.1016/j.chroma.2018.03.004.

152

Handbook of Nanomaterials in Analytical Chemistry

[162] N.H.H. Hairom, A.W. Mohammad, A.A.H. Kadhum, Influence of zinc oxide nanoparticles in the nanofiltration of hazardous Congo red dyes, Biochem. Eng. J. 260 (2015) 907 915. Available from: https://doi.org/10.1016/j.cej.2014.08.068. [163] Y. Yu, Q. Zhang, Z. Wang, J. Pu, A graphene oxide nanofiltration membrane intercalated with cellulose nano-crystals, Bioresources 13 (4) (2018) 9116 9131. [164] M. Stadermann, A.D. McBrady, B. Dick, V.R. Reid, A. Noy, R.E. Synovec, et al., Ultrafast gas chromatography on single-wall carbon nanotube stationary phases in microfabricated channels, Anal. Chem. 78 (2006) 5639. [165] H. Shakeel, M. Agah, Self-patterned gold-electroplated multicapillary gas, J. Microelectromech. Syst. 22 (1) (2013) 62 70. [166] J. Vial, D. Thie´baut, F. Marty, P. Guibal, R. Haudebourg, K. Nachef, et al., Silica sputtering as a novel collective stationary phase deposition for microelectromechanical system gas chromatography column: feasibility and first separations, J. Chromatogr. A 1218 (21) (2011) 3262 3266. Available from: https://doi.org/10.1016/j.chroma.2010.12.035. [167] T. Zhao, G. Zhou, Y. Wu, X. Liu, F. Wang, Gold nanomaterials based pseudostationary phases in capillary electrophoresis: a brand-new attempt at chondroitin sulfate isomers separation, Electrophoresis 36 (4) (2015) 588 595. Available from: https://doi. org/10.1002/elps.201400440. [168] D.-Y. Kang, N.A. Brunelli, G.I. Yucelen, A. Venkatasubramanian, J. Zang, J. Leisen, et al., Direct synthesis of single-walled aminoaluminosilicate nanotubes with enhanced molecular adsorption selectivity, Nat. Commun. 5 (1) (2014). Available from: https:// doi.org/10.1038/ncomms4342. [169] W.-F. Chan, H. Chen, A. Surapathi, M.G. Taylor, X. Shao, E. Marand, et al., Zwitterion functionalized carbon nanotube/polyamide nanocomposite membranes for water desalination, ACS Nano 7 (6) (2013) 5308 5319. Available from: https://doi. org/10.1021/nn4011494. [170] R. Mahajan, W.J. Koros, Mixed matrix membrane materials with glassy polymers. Part 1, Polym. Eng. Sci. 42 (7) (2002) 1420 1431. Available from: https://doi.org/ 10.1002/pen.11041. [171] N. Li, J. Chen, Y.-P. Shi, Magnetic graphene solid-phase extraction for the determination of carbamate pesticides in tomatoes coupled with high performance liquid chromatography, Talanta 141 (2015) 212 219. Available from: https://doi.org/10.1016/j. talanta.2015.04.018. [172] Z.S. Gong, L.P. Duan, A.N. Tang, Amino-functionalized silica nanoparticles for improved enantiomeric separation in capillary electrophoresis using carboxymethylβ-cyclodextrin (CM-β-CD) as a chiral selector, Microchim. Acta 182 (7 8) (2015) 1297 1304. Available from: https://doi.org/10.1007/s00604-015-1449-0. [173] L.-M. Li, H.-F. Wang, X.-P. Yan, Metal-organic framework ZIF-8 nanocrystals as pseudostationary phase for capillary electrokinetic chromatography, Electrophoresis 33 (18) (2012) 2896 2902. Available from: https://doi.org/10.1002/elps.201200269. [174] M. Li, X. Liu, F. Jiang, L. Guo, L. Yang, Enantioselective open-tubular capillary electrochromatography using cyclodextrin-modified gold nanoparticles as stationary phase, J. Chromatogr. A 1218 (23) (2011) 3725 3729. Available from: https://doi. org/10.1016/j.chroma.2011.04.045. [175] X. Liu, X. Liu, M. Li, L. Guo, L. Yang, Application of graphene as the stationary phase for open-tubular capillary electrochromatography, J. Chromatogr. A 1277 (2013) 93 97. Available from: https://doi.org/10.1016/j.chroma.2012.12.055.

Separation techniques with nanomaterials

153

[176] B. Preinerstorfer, D. Lubda, A. Mucha, P. Kafarski, W. Lindner, M. L¨ammerhofer, Stereoselective separations of chiral phosphinic acid pseudodipeptides by CEC using silica monoliths modified with an anion-exchange-type chiral selector, Electrophoresis 27 (21) (2006) 4312 4320. Available from: https://doi.org/10.1002/elps.200600253. [177] N. Na, Y. Hu, J. Ouyang, W. Baeyens, J. Delanghe, Y. Taes, et al., On the use of dispersed nanoparticles modified with single layer β-cyclodextrin as chiral selecor to enhance enantioseparation of clenbuterol with capillary electrophoresis, Talanta 69 (4) (2006) 866 872. Available from: https://doi.org/10.1016/j.talanta.2005.11.022. [178] L. Zhao, P. Ai, A.-H. Duan, L.-M. Yuan, Single-walled carbon nanotubes for improved enantioseparations on a chiral ionic liquid stationary phase in GC, Anal. Bioanal. Chem. 399 (1) (2010) 143 147. Available from: https://doi.org/10.1007/s00216-010-4079-8. [179] G.D. Tarigh, F. Shemirani, In situ immobilization of a general resolving agent on the magnetic multi-wall carbon nanotube for the direct enantioenrichment of dl-mandelic acid, Talanta 144 (2015) 899 907. Available from: https://doi.org/10.1016/j. talanta.2015.07.035. [180] M. Ahmed, M.M.A. Yajadda, Z.J. Han, D. Su, G. Wang, K.K. Ostrikov, et al., Singlewalled carbon nanotube-based polymer monoliths for the enantioselective nano-liquid chromatographic separation of racemic pharmaceuticals, J. Chromatogr. A 1360 (2014) 100 109. Available from: https://doi.org/10.1016/j.chroma.2014.07.052. [181] Y. Claude Guillaume, C. Andre´, Fast enantioseparation by HPLC on a modified carbon nanotube monolithic stationary phase with a pyrenyl aminoglycoside derivative, Talanta 115 (2013) 418 421. Available from: https://doi.org/10.1016/j.talanta.2013.05.07. [182] J. Yu, D. Huang, K. Huang, Y. Hong, Preparation of hydroxypropyl-β-cyclodextrin cross-linked multi-walled carbon nanotubes and their application in enantioseparation of clenbuterol, Chin. J. Chem. 29 (5) (2011) 893 897. Available from: https://doi.org/ 10.1002/cjoc.201190185. [183] Q. Hu, E. Marand, S. Dhingra, D. Fritsch, J. Wen, G. Wilkes, Poly(amide-imide)/TiO2 nano-composite gas separation membranes: fabrication and characterization, J. Membr. Sci. 135 (1) (1997) 65 79. Available from: https://doi.org/10.1016/s03767388(97)00120-8. [184] W. Li, G.-S. Ding, A.-N. Tang, Enantiomer separation of propranolol and tryptophan using bovine serum albumin functionalized silica nanoparticles as adsorbents, RSC Adv. 5 (114) (2015) 93850 93857. Available from: https://doi.org/10.1039/c5ra17535f. [185] M. Lewin, N. Carlesso, C.H. Tung, X.W. Tang, D. Cory, D.T. Scadden, et al., Tat peptide-derivatized magnetic nanoparticles allow in vivo tracking and recovery of progenitor cells, Nat. Biotechnol. 18 (4) (2000) 410 414. Available from: https://doi.org/ 10.1038/74464. [186] T.-J. Yoon, K.N. Yu, E. Kim, J.S. Kim, B.G. Kim, S.-H. Yun, et al., Specific targeting, cell sorting, and bioimaging with smart magnetic silica core-shell nanomaterials, Small 2 (2) (2006) 209 215. Available from: https://doi.org/10.1002/smll.200500360. [187] M. Labib, R.M. Mohamadi, M. Poudineh, S.U. Ahmed, I. Ivanov, C.-L. Huang, et al., Single-cell mRNA cytometry via sequence-specific nanoparticle clustering and trapping, Nat. Chem. 10 (5) (2018) 489 495. Available from: https://doi.org/10.1038/ s41557-018-0025-8. [188] A. Nowacek, I. Kadiu, J. McMillan, H.E. Gendelman, Methods for isolation and identification of nanoparticle-containing subcellular compartments, Cell. Subcell. Nanotechnol. (2013) 47 55. Available from: https://doi.org/10.1007/978-1-62703-336-7_6.

154

Handbook of Nanomaterials in Analytical Chemistry

[189] H. Mohamed, L.D. McCurdy, D.H. Szarowski, S. Duva, J.N. Turner, M. Caggana, Development of a rare cell fractionation device: application for cancer detection, IEEE Trans. Nanobiosci. 3 (4) (2004) 251 256. Available from: https://doi.org/ 10.1109/tnb.2004.837903. [190] S.L. Sahoo, C.H. Liu, W.C. Wu, Lymphoma cell isolation using multifunctional magnetic nanoparticles: antibody conjugation and characterization, RSC Adv. 7 (36) (2017) 22468 22478. Available from: https://doi.org/10.1039/c7ra02084h. [191] L. Chen, L.L. Wu, Z.L. Zhang, J. Hu, M. Tang, C.B. Qi, et al., Biofunctionalized magnetic nanospheres-based cell sorting strategy for efficient isolation, detection and subtype analyses of heterogeneous circulating hepatocellular carcinoma cells, Biosens. Bioelectron. 85 (2016) 633 640. Available from: https://doi.org/10.1016/j. bios.2016.05.071. [192] L.Y. Ng, A.W. Mohammad, C.P. Leo, N. Hilal, Polymeric membranes incorporated with metal/metal oxide nanoparticles: a comprehensive review, Desalination 308 (2013) 15 33. Available from: https://doi.org/10.1016/j.desal.2010.11.033. [193] S. Yu, X. Zuo, R. Bao, X. Xu, J. Wang, J. Xu, Effect of Sio2 nanoparticle on the characteristic of a new organic-inorganic hybrid membrane, Polymer 50 (2009) 553 559. [194] L.H. Li, J.C. Deng, H.R. Deng, Z.L. Liu, L. Xin, Synthesis and characterization of chitosan/ZnO nanoparticle composite membranes, Carbohydr. Res. 345 (8) (2010) 994 998. Available from: https://doi.org/10.1016/j.carres.2010.03.019. [195] N. Maximous, G. Nakhla, W. Wan, K. Wong, Effect of the metal oxide particle distributions on modified PES membranes characteristics and performance, J. Membr. Sci. 361 (1 2) (2010) 213 222. Available from: https://doi.org/10.1016/j.memsci.2010.05.051. [196] P.M. Biesheuvel, P. Stroeve, P.A. Barneveld, Effect of protein adsorption and ionic strength on the equilibrium partition coefficient of ionizable macromolecules in charged nanopores, J. Phys. Chem. B 108 (45) (2004) 17660 17665. Available from: https://doi.org/10.1021/jp047913q. [197] A. Sungpet, J.D. Way, P.M. Thoen, J.R. Dorgan, Reactive polymer membranes for ethylene/ethane separation, J. Membr. Sci. 136 (1 2) (1997) 111 120. Available from: https://doi.org/10.1016/s0376-7388(97)00158-0. [198] S.W. Kang, K. Char, Y.S. Kang, Prospects of facilitated olefin transport membrane in solid state, Chem. Mater. 20 (2008) 1308. [199] D. Knopp, D. Tang, R. Niessner, Review: bioanalytical applications of biomoleculefunctionalized nanometer-sized doped silica particles, Anal. Chim. Acta 647 (1) (2009) 14 30. Available from: https://doi.org/10.1016/j.aca.2009.05.037. [200] W. Wang, R. Ma, Q. Wu, C. Wang, Z. Wang, Magnetic microsphere-confined graphene for the extraction of polycyclic aromatic hydrocarbons from environmental water samples coupled with high performance liquid chromatography fluorescence analysis, J. Chromatogr. A 1293 (2013) 20 27. Available from: https://doi.org/ 10.1016/j.chroma.2013.03.071. [201] P.S. Goh, A.F. Ismail, N. Hilal, Nano-enabled membranes technology: sustainable and revolutionary solutions for membrane desalination? Desalination 380 (2016) 100 104. Available from: https://doi.org/10.1016/j.desal.2015.06.002. [202] W. Kim, S. Nair, Membranes from nanoporous 1D and 2D materials: a review of opportunities, developments, and challenges, Chem. Eng. Sci. 104 (2013) 908 924. Available from: https://doi.org/10.1016/j.ces.2013.09.047. [203] J. Zhu, J. Hou, A. Uliana, Y. Zhang, M. Tian, B. Van der Bruggen, The rapid emergence of two-dimensional nanomaterials for high-performance separation membranes, J. Mater. Chem. A 6 (9) (2018) 3773 3792. Available from: https://doi.org/10.1039/c7ta10814a.

Separation techniques with nanomaterials

155

[204] N.L. Le, P.H.H. Duong, S.P. Nunes, 1.6 Advanced polymeric and organic inorganic membranes for pressure-driven processes, Compr. Membr. Sci. Eng. (2017) 120 136. Available from: https://doi.org/10.1016/b978-0-12-409547-2.12275. [205] K. Pyrzynska, Sample preparation for chromatography with nanomaterials, Nanomater. Chromatogr. (2018) 233 252. Available from: https://doi.org/10.1016/ b978-0-12-812792-6.00008-x. [206] S. Dahane, M.D. Gil Garcı´a, M.J. Martı´nez Bueno, A. Ucle´s Moreno, M. Martı´nezGalera, A. Derdour, Determination of drugs in river and wastewaters using solid-phase extraction by packed multi-walled carbon nanotubes and liquid chromatography quadrupole-linear ion trap-mass spectrometry, J. Chromatogr. A 1297 (2013) 17 28. Available from: https://doi.org/10.1016/j.chroma.2013.05.002. [207] P. Kueseng, C. Thammakhet, P. Thavarungkul, P. Kanatharana, Multiwalled carbon nanotubes/cryogel composite, a new sorbent for determination of trace polycyclic aromatic hydrocarbons, Microchem. J. 96 (2) (2010) 317 323. Available from: https:// doi.org/10.1016/j.microc.2010.05.002. [208] Y. Liu, H. Li, J. Lin, Magnetic solid-phase extraction based on octadecyl functionalization of monodisperse magnetic ferrite microspheres for the determination of polycyclic aromatic hydrocarbons in aqueous samples coupled with gas chromatography mass spectrometry, Talanta 77 (3) (2009) 1037 1042. Available from: https://doi.org/10.1016/j.talanta.2008.08.013. [209] S.-W. Xue, M.-Q. Tang, L. Xu, Z. Shi, Magnetic nanoparticles with hydrophobicity and hydrophilicity for solid-phase extraction of polycyclic aromatic hydrocarbons from environmental water samples, J. Chromatogr. A 1411 (2015) 9 16. Available from: https://doi.org/10.1016/j.chroma.2015.07.104. ´. [210] A.V. Herrera-Herrera, J. Herna´ndez-Borges, M.M. Afonso, J.A. Palenzuela, M.A Rodrı´guez-Delgado, Comparison between magnetic and non magnetic multi-walled carbon nanotubes-dispersive solid-phase extraction combined with ultra-high performance liquid chromatography for the determination of sulfonamide antibiotics in water samples, Talanta 116 (2013) 695 703. Available from: https://doi.org/10.1016/ j.talanta.2013.07.060. [211] W. Li, E. Rea´tegui, M.-H. Park, S. Castleberry, J.Z. Deng, B. Hsu, et al., Biodegradable nano-films for capture and non-invasive release of circulating tumor cells, Biomaterials 65 (2015) 93 102. Available from: https://doi.org/10.1016/j.biomaterials.2015.06.036 (109). ´ . Rodrı´guez[212] B. Socas-Rodrı´guez, J. Herna´ndez-Borges, P. Salazar, M. Martı´n, M.A Delgado, Core shell polydopamine magnetic nanoparticles as sorbent in microdispersive solid-phase extraction for the determination of estrogenic compounds in water samples prior to high-performance liquid chromatography mass spectrometry analysis, J. Chromatogr. A 1397 (2015) 1 10. Available from: https://doi.org/ 10.1016/j.chroma.2015.04.010. [213] Q. Li, M.H.W. Lam, R.S.S. Wu, B. Jiang, Rapid magnetic-mediated solid-phase extraction and pre-concentration of selected endocrine disrupting chemicals in natural waters by poly (divinylbenzene-co-methacrylic acid) coated Fe3O4 core-shell magnetite microspheres for their liquid chromatography tandem mass spectrometry determination, J. Chromatogr. A 1217 (8) (2010) 1219 1226. Available from: https://doi.org/10.1016/j.chroma.2009.12.035. [214] R.A. Pe´rez, B. Albero, J.L. Tadeo, E. Molero, C. Sa´nchez-Brunete, Analysis of steroid hormones in water using palmitate-coated magnetite nanoparticles solid-phase extraction and gas chromatography tandem mass spectrometry, Chromatographia 77 (11 12) (2014) 837 843. Available from: https://doi.org/10.1007/s10337-014-2688-7.

156

Handbook of Nanomaterials in Analytical Chemistry

[215] X. Zhao, Y. Cai, F. Wu, Y. Pan, H. Liao, B. Xu, Determination of perfluorinated compounds in environmental water samples by high-performance liquid chromatography-electrospray tandem mass spectrometry using surfactant-coated Fe3O4 magnetic nanoparticles as adsorbents, Microchem. J. 98 (2) (2011) 207 214. Available from: https://doi.org/10.1016/j.microc.2011.01.011. [216] X. Liang, Y. Zou, S. Liu, C. Chen, J. Wang, H. Hu, et al., Facile and robust dual interaction modification of hexadecyldimethyl amine magnetic nanoparticles for the ultrasensitive analysis of perfluorinated compounds in environmental water, J. Sep. Sci. 38 (8) (2015) 1394 1401. Available from: https://doi.org/10.1002/jssc.201401119. [217] Z. Es’haghi, E. Esmaeili-Shahri, Sol gel-derived magnetic SiO2/TiO2 nanocomposite reinforced hollow fiber-solid phase microextraction for enrichment of non-steroidal anti-inflammatory drugs from human hair prior to high performance liquid chromatography, J. Chromatogr. B 973 (2014) 142 151. Available from: https://doi.org/ 10.1016/j.jchromb.2014.09.030. [218] I. Ma´rquez-Sillero, E. Aguilera-Herrador, S. Ca´rdenas, M. Valca´rcel, Determination of parabens in cosmetic products using multi-walled carbon nanotubes as solid phase extraction sorbent and corona-charged aerosol detection system, J. Chromatogr. A 1217 (1) (2010) 1 6. Available from: https://doi.org/10.1016/j.chroma.2009.11.005. [219] L. Li, Y. Huang, Y. Wang, W. Wang, Hemimicelle capped functionalized carbon nanotubes-based nanosized solid-phase extraction of arsenic from environmental water samples, Anal. Chim. Acta 631 (2) (2009) 182 188. Available from: https://doi.org/ 10.1016/j.aca.2008.10.043. [220] K. Pyrzynska, Carbon nanostructures for separation, preconcentration and speciation of metal ions, TrAC, Trends Anal. Chem. 29 (7) (2010) 718 727. Available from: https://doi.org/10.1016/j.trac.2010.03.013. [221] B. Zawisza, A. Baranik, E. Malicka, E. Talik, R. Sitko, Preconcentration of Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Pb(II) with ethylenediamine-modified graphene oxide, Microchim. Acta 183 (1) (2015) 231 240. Available from: https://doi.org/ 10.1007/s00604-015-1629-y. [222] Capillary electrophoresis, ,https://chem.libretexts.org/Bookshelves/Analytical_Chemistry/ Supplemental_Modules_(Analytical_Chemistry)/Instrumental_Analysis/ Capillary_Electrophoresis., 2019. [223] Y. Moliner-Martı´nez, S. Ca´rdenas, B.M. Simonet, M. Valca´rcel, Recent developments in capillary EKC based on carbon nanoparticles, Electrophoresis 30 (1) (2009) 169 175. Available from: https://doi.org/10.1002/elps.200800314. ´ . Gonza´lez-Curbelo, D.A. Varela-Martı´nez, B. Socas-Rodrı´guez, J. Herna´ndez[224] M.A Borges, Recent applications of nanomaterials in capillary electrophoresis, Electrophoresis 38 (19) (2017) 2431 2446. Available from: https://doi.org/10.1002/elps.201700178. [225] Y.-J. Lin, J.-Y. Yang, T.-Y. Shu, T.-Y. Lin, Y.-Y. Chen, M.-Y. Su, et al., Detection of C-reactive protein based on magnetic nanoparticles and capillary zone electrophoresis with laser-induced fluorescence detection, J. Chromatogr. A 1315 (2013) 188 194. Available from: https://doi.org/10.1016/j.chroma.2013.09.042. [226] K. Zhang, M. Cao, C. Lou, S. Wu, P. Zhang, M. Zhi, et al., Graphene-coated polymeric anion exchangers for ion chromatography, Anal. Chim. Acta 970 (2017) 73 81. Available from: https://doi.org/10.1016/j.aca.2017.03.015. [227] I.N. Savina, C.J. English, R.L.D. Whitby, Y. Zheng, A. Leistner, S.V. Mikhalovsky, et al., High efficiency removal of dissolved As(III) using iron nanoparticle-embedded macroporous polymer composites, J. Hazard. Mater. 192 (3) (2011) 1002 1008. Available from: https://doi.org/10.1016/j.jhazmat.2011.06.003.

Separation techniques with nanomaterials

157

[228] K. Yao, S. Shen, J. Yun, L. Wang, F. Chen, X. Yu, Protein adsorption in supermacroporouscryo gels with embedded nanoparticles, Biochem. Eng. J. 36 (2) (2007) 139 146. Available from: https://doi.org/10.1016/j.bej.2007.02.009. [229] A. Aqel, K. Yusuf, Z.A. Al-Othman, A.Y. Badjah-Hadj-Ahmed, A.A. Alwarthan, Effect of multi-walled carbon nanotubes incorporation into benzyl methacrylate monolithic columns in capillary liquid chromatography, Analyst 137 (18) (2012) 4309. Available from: https://doi.org/10.1039/c2an35518c. [230] F. Ramezani, Protein bands detection by nanoparticles after paper chromatography, Int. J. Nanosci. Nanotechnol 8 (3) (2012) 181 184. [231] Y. Zhong, W. Zhou, P. Zhang, Y. Zhu, Preparation, characterization, and analytical applications of a novel polymer stationary phase with embedded or grafted carbon fibers, Talanta 82 (4) (2010) 1439 1447. Available from: https://doi.org/10.1016/j. talanta.2010.07.01. [232] B. Alfeeli, M.A. Zareian-Jahromi, M. Agah, Micro preconcentrator with seedless electroplated gold as self-heating adsorbent, in: Eighth IEEE Conference on Sensors, Christchurch, New Zealand, 2009, pp. 1947 1950. [233] R. Haudebourg, J. Vial, D. Thiebaut, K. Danaie, J. Breviere, P. Sassiat, et al., Temperature-programmed sputtered micromachined gas chromatography columns: an approach to fast separations in oilfield applications, Anal. Chem. 85 (1) (2012) 114 120. Available from: https://doi.org/10.1021/ac3022136. [234] Q. Li, D. Yuan, Evaluation of multi-walled carbon nanotubes as gas chromatographic column packing, J. Chromatogr. A 1003 (1 2) (2003) 203 209. Available from: https://doi.org/10.1016/s0021-9673(03)00848-3. [235] N. Na, X. Cui, T. De Beer, T. Liu, T. Tang, M. Sajid, et al., The use of silica nanoparticles for gas chromatographic separation, J. Chromatogr. A 1218 (28) (2011) 4552 4558. Available from: https://doi.org/10.1016/j.chroma.2011.05.043. [236] J. Fan, M. Qi, R. Fu, L. Qu, Performance of graphene sheets as stationary phase for capillary gas chromatographic separations, J. Chromatogr. A 1399 (2015) 74 79. Available from: https://doi.org/10.1016/j.chroma.2015.04.030. [237] Q. Qu, Y. Shen, C. Gu, Z. Gu, Q. Gu, C. Wang, et al., Capillary column coated with graphene oxide as stationary phase for gas chromatography, Anal. Chim. Acta 757 (2012) 83 87. Available from: https://doi.org/10.1016/j.aca.2012.10.032. [238] K. Scholten, W.R. Collin, X. Fan, E.T. Zellers, Nanoparticle-coated micro-optofluidic ring resonator as a detector for microscale gas chromatographic vapor analysis, Nanoscale 7 (20) (2015) 9282 9289. Available from: https://doi.org/10.1039/c5nr01780g. [239] F.Y. Chen, W.C. Chang, R.S. Jian, C.J. Lu, Novel gas chromatographic detector utilizing the localized surface plasmon resonance of a gold nanoparticle monolayer inside a glass capillary, Anal. Chem. 86 (11) (2014) 5257 5264. Available from: https://doi. org/10.1021/ac4031829. [240] P.-Y. Lin, G.-Y. Le, W.-I. Chiu, R.-S. Jian, C.-J. Lu, A single light spot GC detector employing localized surface plasmon resonance of porous Au@SiO2 nanoparticle multilayer, Analyst (2019). Available from: https://doi.org/10.1039/c8an01921e. [241] E.L. Laura, Gold Nanoparticle Chemiresistor Arrays for Micro-Gas Chromatography Applications (Ph.D. thesis), The University of Michigan, 2012. [242] F. Xiang, Y. Lin, J. Wen, D.W. Matson, R.D. Smith, An integrated microfabricated device for dual microdialysis and on-line ESI-ion trap mass spectrometry for analysis of complex biological samples, Anal. Chem. 71 (8) (1999) 1485 1490. Available from: https://doi.org/10.1021/ac981400w.

158

Handbook of Nanomaterials in Analytical Chemistry

[243] J.J. Lee, K.J. Jeong, M. Hashimoto, A.H. Kwon, A. Rwei, S.A. Shankarappa, et al., Synthetic ligand-coated magnetic nanoparticles for microfluidic bacterial separation from blood, Nano Lett. 14 (1) (2013) 1 5. Available from: https://doi.org/10.1021/ nl3047305. [244] W. Lee, D. Kwon, W. Choi, G.Y. Jung, A.K. Au, A. Folch, et al., 3D-printed microfluidic device for the detection of pathogenic bacteria using size-based separation in helical channel with trapezoid cross-section, Sci. Rep. 5 (1) (2015). Available from: https://doi.org/10.1038/srep07717. [245] A. Bahadorimehr, Z. Rashemi, B.Y. Majlis, The influence of magnetic nanoparticles’ size on trapping efficiency in a microfluidic device, IJBBB 5 (2) (2015) 132 139. Available from: https://doi.org/10.17706/ijbbb.2015.5.2.132-139. [246] J. Hu, M. Xie, C.Y. Wen, Z.L. Zhang, H.Y. Xie, A.A. Liu, et al., A multicomponent recognition and separation system established via fluorescent, magnetic, dual encoded multifunctional bioprobes, Biomaterials 32 (4) (2011) 1177 1184. Available from: https://doi.org/10.1016/j.biomaterials.2010.10.015. [247] H. Xu, Z.P. Aguilar, L. Yang, M. Kuang, H. Duan, Y. Xiong, et al., Antibody conjugated magnetic iron oxide nanoparticles for cancer cell separation in fresh whole blood, Biomaterials 32 (36) (2011) 9758 9765. Available from: https://doi.org/ 10.1016/j.biomaterials.2011.08.076. [248] W. Hong, S. Lee, H.J. Chang, E.S. Lee, Y. Cho, Multifunctional magnetic nanowires: a novel breakthrough for ultrasensitive detection and isolation of rare cancer cells from non-metastatic early breast cancer patients using small volumes of blood, Biomaterials 106 (2016) 78 86. Available from: https://doi.org/10.1016/j. biomaterials.2016.08.020. [249] J. Bu, Y.J. Kim, Y.T. Kang, T.H. Lee, J. Kim, Y.H. Cho, et al., Polyester fabric sheet layers functionalized with graphene oxide for sensitive isolation of circulating tumor cells, Biomaterials 125 (2017) 1 11. Available from: https://doi.org/10.1016/j. biomaterials.2017.02.009. [250] K.H. Cheong, D.K. Yi, J.-G. Lee, J.-M. Park, M.J. Kim, J.B. Edel, et al., Gold nanoparticles for one step DNA extraction and real-time PCR of pathogens in a single chamber, Lab Chip 8 (5) (2008) 810. Available from: https://doi.org/10.1039/ b717382b. [251] B. Zhang, M. Xie, L. Bruschweiler-Li, R. Bru¨schweiler, Nanoparticle-assisted metabolomics, Metabolites 8 (1) (2018) 21. Available from: https://doi.org/10.3390/ metabo8010021.

Further reading J.J. Lai, J.M. Hoffman, M. Ebara, A.S. Hoffman, C. Estourne`s, A. Wattiaux, et al., Dual magnetic-/temperature-responsive nanoparticles for microfluidic separations and assays, Langmuir 23 (13) (2007) 7385 7391. Available from: https://doi.org/10.1021/ la062527g. G. Saini, D.S. Jensen, L.A. Wiest, M.A. Vail, A. Dadson, M.L. Lee, et al., Core shell diamond as a support for solid-phase extraction and high-performance liquid chromatography, Anal. Chem. 82 (11) (2010) 4448 4456. Available from: https://doi.org/10.1021/ ac1002068.

Membrane applications of nanomaterials

7

Ru¨stem Kec¸ili1, Sibel Bu¨yu¨ktiryaki1 and Chaudhery Mustansar Hussain2 1 Yunus Emre Vocational School of Health Services, Department of Medical Services and Techniques, Anadolu University, Eski¸sehir, Turkey, 2Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, NJ, United States

7.1

Introduction

Membrane technology is widely applied in different separation processes such as treatment of wastewater, gas separation, and desalination [1 9]. Membrane separation is generally performed on the basis of selective transport of the target compound across the membrane structure [10]. Nanofiltration and reverse osmosis membranes are commonly used for the treatment of wastewater samples. However, thick separating layer restricts their water flux behavior. This drawback can be overcome by incorporating nanomaterials (i.e., graphene, fullerenes, carbon nanotubes, and nanoparticles) into the membrane structure. The combination of membranes with excellent features of nanomaterials provides excellent physical and chemical stability, and also high rejection toward the target compound to be separated from the sample. Nanomaterials have gained great attention from many researchers as they display unique properties such as high physical and chemical stability, versatile chemistry for the functionalization, and high surface area [11 15]. The chemical features of nanomaterials in the scale between 1 and 100 nm are completely different compared to the materials in micro- and macroscale. If the size of a material decreases, its surface area increases. This feature is crucial for the binding processes. More binding sites exist on the nanomaterial surface. This chapter provides an overview of the latest progresses and examples of new nanomaterial-based membranes. It starts with brief information about the traditional membrane materials. Then, carbon nanomaterial-based membranes including graphene-based, carbon nanotube-based, and fullerene-based membranes are described. In the final sections, nanoparticle-based and molecularly imprinted polymer (MIP)-based membranes and their applications are demonstrated.

7.2

Traditional membranes

The design and development of new generation membrane materials has received great interest by the researchers in the past decades. However, the industrial Handbook of Nanomaterials in Analytical Chemistry. DOI: https://doi.org/10.1016/B978-0-12-816699-4.00007-4 Copyright © 2020 Elsevier Inc. All rights reserved.

160

Handbook of Nanomaterials in Analytical Chemistry

applications of nanotechnology-based novel membranes are still under development. Most of the traditional membranes are still prepared by using polymers and inorganic materials, and are applied for the separation processes in industry. A type of these traditional membranes is ceramic membranes, which are commonly produced by using metal hydroxides (e.g., ZnO and Al2O3) on the surface of porous supporting materials [16,17]. These kind of membranes are widely applied for the industrial separation processes. In addition to their increased chemical stability and mechanical resistance, they can easily be recovered after fouling [18]. However, ceramic membranes have some disadvantages such as high operation costs and their brittle structure, which limit their applications in large scale [19 21]. Polymer-based membranes are also promising materials in separation processes, as they are low-cost materials and show high performance. Polymer-based porous membranes are generally prepared by using mechanical stretching and phaseinversion process. Although this type of membranes show great separation performance toward the target compound, they have some drawbacks such as stability under extreme operational conditions, for example, corrosive environments, organic solvents, high pressure and temperature values. Recently, the thin film-based membranes, which are the major breakthrough in the membrane science, have received a great interest for the separation applications. These composite membrane materials with selective thin layers and the supporting layers are highly flexible for the separation medium [22]. However, the thin-filmbased membranes exhibit some limitations such as compaction effects caused by multilayer structure under pressure. At higher pressure values, the polymeric structure is reorganized to the tighter fitting structure, which leads to lower porosity and lower efficiency in separation process [23].

7.3

Carbon nanomaterial-based membranes

As the carbon nanomaterials have unique features such as excellent mechanical, chemical, and thermal stabilities, large surface area, great optical features, and lower density, they are extensively used in the fabrication of novel nanocomposite membranes. The incorporation of carbon nanomaterials such as graphene, carbon nanotubes, and fullerenes into the membrane structure is commonly applied in the development of nanocomposite membranes [24]. The combination of nanomaterials with the membranes not only provides high physical and chemical stability, also high rejection, and flux behaviors of the developed nanocomposite membranes, but also introduces various features such as catalytic and antibacterial properties [25,26].

7.3.1 Graphene-based membranes Graphene was discovered by Geim and Novoselov in 2004 [27]. Since then, so much efforts were put into the design and development of new graphene-based

Membrane applications of nanomaterials

161

functional materials. Owing to the excellent hydrophobic feature of graphene, it was widely used in the preparation of functional materials with superhydrophobic features. Recently, these superhydrophobic functional materials were efficiently applied for the separation of water oil mixture [28,29]. Graphene oxide (GO), which is the oxidation state of graphene, is a promising candidate as it has various functional groups such as carboxylic acid, hydroxyl, and epoxide that provide good compatibility with other materials such as polymeric composite membranes. When GO is incorporated in the polymeric membrane structure, the mechanical features of the polymer are significantly improved [30]. The horizontal orientation of the GO in the polymeric membrane structure provides a barrier of GO nanolayers, as the nanolayers hinder the diffusion of permeating molecules of the target compound. Prince et al. [31] proposed a facile method to improve the hydrophilic feature of the polyethersulfone hollow fiber ultrafiltration membrane. For this purpose, graphene-attached polyacrylonitrile-co-maleimide having hydroxyl, carboxyl, and amine functional groups was prepared. The characterization of the prepared graphene-based nanocomposite membranes was performed by using scanning electron microscope (SEM), energy-dispersive X-ray analyses, pore size, and contact angle measurements. The results showed that the incorporation of grapheneattached polyacrylonitrile-co-maleimide into the polyethersulfone hollow fiber membrane leads to a decrease of water contact angle (64.5% decrease). On the other hand, oil contact angle increased from 43.6 degrees to 112.5 degrees compared to the control membrane. The water permeability of the prepared graphenebased nanocomposite membrane was enhanced by 43% and the efficient removal of oil was successfully achieved with a rate of 99%. In another research carried out by Nasseri et al. [32], GO/polysulfone nanocomposite membrane was prepared for the efficient removal of bisphenol A from water samples. For this purpose, three different membranes were prepared by using phase-inversion technique. The obtained results indicated that incorporation of GO into the membrane structure considerably increased the permeate flux of the prepared nanocomposite membranes. The maximum bisphenol A (BPA) removal was achieved by using the GO (0.4%)/polysulfone nanocomposite membrane which has the highest negative zeta potential value (210.46 mV). The optimum process conditions for BPA removal such as time, initial BPA concentration, pressure, and pH were determined as 10.6 min, 7.5 mg L21, 1.02 bar, and 5.5, respectively. Under optimum conditions, the removal efficiency of the target pollutant BPA by using the prepared GO (0.4 %)/polysulfone membrane was obtained as 93%. Zhang and coworkers developed a GO-based polyacrylonitrile fiber nanocomposite membrane for the filtration of water oil emulsion [33]. In their study, polyacrylonitrile nanofibers were produced by electrospinning technique and GO was assembled on the surface of nanofibers. The prepared GO-based polyacrylonitrile nanocomposite membrane exhibited superhydrophilic feature and low oil-adhesion behavior. The developed nanocomposite membrane exhibited great rejection value ($98%) and antifouling performance.

162

Handbook of Nanomaterials in Analytical Chemistry

Zhu and colleagues developed a nanocomposite membrane composed of porous reduced GO (RGO) and halloysite nanotubes (HNTs) the removal of salts and dye compounds from water sa [34]. HNTs were used to increase the interlayer spacing of GO (Fig. 7.1). After characterization studies by using transmission electron microscopy (TEM), X-Ray diffraction (XRD) spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, Raman, and energy-dispersive spectroscopy (EDS), the prepared sandwich-like nanocomposite membrane was successfully applied for the removal of MgCl2, NaCl, MgSO4, Na2SO4, and Reactive Black 5 dye from water samples. In another interesting study, Hu and colleagues developed a GO-based nanocomposite membrane [35]. The prepared nanocomposite membrane was effectively used for the treatment of water oil emulsion. The obtained values for water flux of the prepared nanocomposite membrane having GO and control membrane without GO were 677 and 522 L h21 m2 bar21, respectively after 2.5 h filtration time. On the other hand, the achieved oil rejections of the prepared GO-based nanocomposite membrane and unmodified control membrane were found as 98.7% and 98.1%, respectively after 2 h filtration time. It has been reported that incorporation of GO into the membrane structure has significantly increased the performance of the membranes for the separation of water oil emulsions. Ho and coworkers reported the design and preparation of novel GO-multiwalled carbon nanotubes (MWCNTs)-based polyvinylidene fluoride nanocomposite membrane for the treatment of palm oil mill effluent [36]. The nanocomposite membrane was prepared by using in situ colloidal precipitation technique. The rejection

Figure 7.1 The schematic demonstration of the fabrication of GO-based nanocomposite membrane. Source: Reproduced with permission from L. Zhu, H. Wang, J. Bai, J. Liu, Y. Zhang, A porous graphene composite membrane intercalated by halloysite nanotubes for efficient dye desalination, Desalination 420 (2017) 145 157.

Membrane applications of nanomaterials

163

ability of the prepared GO-MWCNTs-based nanocomposite membrane was investigated using palm oil mill effluent. The obtained results indicated that the developed nanocomposite membrane can be successfully used for the treatment of palm oil mill effluent. The rejection values of phosphorus, chemical oxygen demand, total dissolved solids, hardness, turbidity, total suspended solids, chlorine, and color were enhanced by 6.55%, 75.5%, 1.51%, 21.79%, 81.94%, 100%, 76%, and 86.3%, respectively using GO-MWCNTs-based nanocomposite membrane compared to the control membrane without GO and MWCNTs.

7.3.2 Carbon nanotubes-based membranes Since the discovery of CNTs in 1991 [37], many researchers focused on the use of CNTs in different applications. CNTs are cylindrical structures that consist of rolled graphene sheets and categorized as MWCNTs and single-walled carbon nanotubes. CNTs have many superiorities such as excellent oleophobicity and hydrophilicity [38], high mechanical [39], electrical [40], and thermal features [41]. The combination of these unique features with the membrane systems can be successfully carried out for the design and preparation of novel nanocomposite membranes. In another work published by Zhang et al. [42], a novel MWCNT GO-based nanocomposite membrane was designed and prepared for the filtration of Sr21 ions from wastewater. For this purpose, the preparation of GO membranes that are interlinked with MWCNTs on the surface of polyacrylonitrile support was carried out. Then, the prepared nanocomposite membrane was effectively used for the removal of Sr21 ions from wastewater. The results showed that the prepared nanocomposite membrane displayed excellent water flux behavior (four times higher) compared to the conventional membranes. The rejection value for Sr21 EDTA chelate was obtained as 93.4%. In another research [43], Mahdavi and his colleagues developed MWCNT-based piperazine/polyamide nanocomposite membranes for the salt removal from water samples. In their study, oxidized and raw MWCNTs were used in the preparation of different nanocomposite membranes. The antifouling features, permeation and salt rejection behaviors of the prepared raw and oxidized MWCNT-embedded nanocomposite membranes and unmodified piperazine/polyamide membranes were investigated in detail. The results showed that the incorporation of oxidized and raw MWCNTs into the membrane structure significantly increased the salt removal performance of the piperazine/polyamide membranes. Hudaib et al. prepared MWCNT-based polyaniline-poly(vinylidene fluoride) nanocomposite membranes for the humic acid removal from water [44]. For this purpose, the polymerization of aniline with various amounts of MWCNTs (in the range between 0.25 wt.% and 2.0 wt.%) was carried out by using in situ polymerization technique (Fig. 7.2). Then, MWCNT-based polyaniline-poly(vinylidene fluoride) nanocomposite membranes were prepared. The results indicated that the prepared polyaniline-poly(vinylidene fluoride) nanocomposite membrane having 1.5 wt.% MWCNTs displayed the maximum permeability. In addition, the

164

Handbook of Nanomaterials in Analytical Chemistry

Figure 7.2 The synthesis of MWCNT-polyaniline (PANI). Source: Reproduced with permission from B. Hudaib, V. Gomes, J. Shi, C. Zhou, Z. Liu, Poly (vinylidene fluoride)/polyaniline/MWCNT nanocomposite ultrafiltration membrane for natural organic matter removal, Sep. Purif. Technol. 190 (2018) 143 155.

MWCNT-based nanocomposite membrane successfully removed humic acid from water samples with a rejection value of 79%. Shahzad and coworkers reported the fabrication of MWCNTs-Al2O3-based nanocomposite membranes for the effective removal of Cd21 ions from aqueous solutions [45]. The effects of various paramaters such as sintering temperature and initial compaction load on the water flux behavior, strength, and porosity of the MWCNT-Al2O3-based nanocomposite membranes were investigated. In the final step, the prepared nanocomposite membranes were used for Cd21 removal from aqueous solutions in batch mode. The results confirmed that 93% of Cd21 ions in aqueous solutions were successfully removed by using the prepared nanocomposite membranes. In an interesting study reported by Saadati and Pakizeh [46], MWCNT-based Pebax-poly(sulfone) nanocomposite membrane was prepared for the separation of water oil emulsion. In this study, different amounts of MWCNTs in the range from 0.5 wt.% to 2.0 wt.% were incorporated into the membrane structure. Thermal stability and hydrophilicity of the prepared nanocomposite membrane increased at higher loading of MWCNTs into the membrane structure. The maximum rejection of oil was achieved using the nanocomposite membrane having 2.0 wt.% MWCNTs.

Membrane applications of nanomaterials

165

Zhang et al. developed CNT-based nanocomposite membranes for the efficient separation of oil water and catalytic decomposition [38]. For this purpose, polystyerene (PS) microspheres were modified with 3-aminopropyl triethoxysilane and Au nanoparticles (Au NPs) were attached to the modified PS microsphere membrane. Then, CNTs layer was deposited on the surface of Au NPs-PS microsphere membrane (Fig. 7.3). The obtained CNT-based nanocomposite membrane was successfully used for the catalytic decomposition of nitrophenol (92.6% decomposition) from oil contaminated water samples and efficient separation of oil water emulsion. In another important research [47], CNT-based nanocomposite membranes for the treatment of water oil emulsions were prepared by Gu and colleagues. In their study, polyacrylic acid was grafted on the CNTs and Ag nanoparticles were then immobilized. The results confirmed that the obtained CNT-based nanocomposite membranes exhibited excellent superoleophobic features toward different organic solvents such as carbon tetrachloride and dichloromethane. In addition, CNT-based nanocomposite membranes showed high superhydrophilicity. The results also indicated that the prepared nanocomposite membranes can be efficiently used for the separation of of water oil emulsions. It was reported that incorporation of Ag

Figure 7.3 The schematic demonstration of the preparation of CNT-based Au NPs-PS nanocomposite membrane. Source: Reproduced with permission from L. Zhang, J. Gu, L. Song, L. Chen, Y. Huang, J. Zhang, et al., Underwater superoleophobic carbon nanotubes/core-shell polystyrene@Au nanoparticles composite membrane for flow-through catalytic decomposition and oil/water separation, J. Mater. Chem. A 4(28) (2016) 10810 10815.

166

Handbook of Nanomaterials in Analytical Chemistry

nanoparticles into the nanocomposite membrane structure provides high antibacterial feature that may open a new perspective for the design and development of multifunctional membranes for the separation processes. Maphutha et al. developed a CNT-based nanocomposite membrane having polyvinyl alcohol layer for the separation of oil from contaminated wastewater [48]. For this purpose, chemical vapor-deposition technique was used for the synthesis of CNTs. Then, CNTs were incorporated into the membrane structure. The prepared CNT-based nanocomposite membrane displayed high water flux behavior with excellent rejection of oil from wastewater (over 95%). Gu and coworkers reported the preparation of CNT-based nanocomposite membranes with superhydrophobic feature for the efficient removal of oil from water samples [49]. In this study, CNTs were first immobilized on the surface of Al2O3 membrane. Then, covalent attachment of PS to the membrane surface was carried out. Fig. 7.4 shows the schematic demonstration of the fabrication of CNT-PS nanocomposite membrane. The prepared nanocomposite membrane was successfully applied for the separation of oil water emulsion. The efficiency of separation and water flux value was obtained as 99.94% and 5000 L m22 h21 bar21.

7.3.3 Fullerene-based membranes Fullerenes are a class of carbon allotropes that consists of 60 C atoms organized in hexagons and pentagons. The main difference between fullerenes and CNTs is their shape. Fullerenes are cage-like structures while the CNTs are tube-like structures in nanoscale [50,51]. Fullerenes as effective nanomaterials were also incorporated into membrane structures and the developed fullerene-based nanocomposite membranes were successfully used for the treatment of environmental samples such as wastewater. For example, Chen and coworkers developed a nanocomposite membrane composed of polyvinyl butyral/polyvinylidene fluoride and fullerene coated with F-127 [52].

Figure 7.4 The schematic demonstration of the fabrication of CNT-PS nanocomposite membrane for water oil separation. Source: Reproduced with permission from J. Gu, P. Xiao, J. Chen, F. Liu, Y. Huang, G. Li, et al., Robust preparation of superhydrophobic polymer/carbon nanotube hybrid membranes for highly effective removal of oils and separation of water-in-oil emulsions, J. Mater. Chem. A 2(37) (2014) 15268-15272.

Membrane applications of nanomaterials

167

The characterization studies of the prepared nanocomposite membrane were performed by using FT-IR, SEM, XPS, atomic force microscope (AFM), and thermal gravimetric analysis (TGA). Then, the prepared nanocomposite membrane was successfully used for the separation of bovine serum albumin, ovalbumin, and bromelain from wastewater samples. The obtained highest rejection value for the target proteins was B98.6%. In another interesting study, a fullerene-based sulfonated polyvinyl alcohol nanocomposite membrane for the removal of Cu21 ions from wastewater was developed by Rikame et al. [53]. The developed fullerene-based nanocomposite membrane showed high removal performance toward Cu21 ions in wastewater and the highest removal degree was found as 73.2%. Jin et al. reported the preparation of fullerene-based composite membranes for the estrone removal from aqueous samples [54]. In this research, poly(2, 6-dimethyl-1, 4-phenylene oxide) was modified with fullerene. Two types of nanocomposite membrane were prepared by using different amounts of fullerene (2% and 10%). The results confirmed that the prepared nanocomposite membrane having 10% fullerene exhibited great binding behavior toward the target compound estrone (B95% binding). Another fullerene-based nanocomposite membranes were developed by Saga and colleagues [55]. In their study, fullerene and sulfonated polystyrene were used for the preparation of nanocomposite membranes. The incorporation of the fullerene into the membrane structure significantly improved the oxidation resistance and decreased the methanol permeability while the mechanical strength of the membrane was not affected. The results showed that the prepared fullerene-based nanocomposite membranes displayed 30% and 50% lower methanol permeability values than Nafion 117 membrane and polystyrene membrane, respectively.

7.4

Nanoparticle-based membranes

Nanoparticle-based membranes are also popular materials, which are commonly used for separation processes. For example, Yu et al. prepared yttrium nanoparticlebased polysulfone membrane modified with polyvinyl alcohol for the efficient separation of arsenate from water [56]. In this study, yttrium nanoparticles were embedded into the structure of polysulfone membrane having polyvinyl alcohol layer. The developed yttrium nanoparticle-based membrane displayed high removal performance for arsenate in water. The obtained maximum binding capacity of the membrane was 35.56 mg g21 at pH 7.0. In another interesting study [57], gold nanoparticle-based polydopamine (pDA)polyethyleneimine nanocomposite membranes were developed for the efficient removal of salts from water samples. For this purpose, codeposition of pDA and polyethyleneimine in the presence of gold nanoparticles was carried out. The prepared nanocomposite membranes successfully removed bivalent cations such as ZnCl2, BaCl2, NiCl2, and CdCl2, where the obtained rejection values were 88.3%,

168

Handbook of Nanomaterials in Analytical Chemistry

90.6%, 90.4%, and 86.8%, respectively. The results also showed that the prepared gold nanoparticle-based composite membranes exhibited excellent antibacterial activity toward Escherichia coli and Staphylococcus aureus. Akbari and colleagues reported the preparation of polyethylene nanocomposite membranes having silica nanoparticles for humic acid removal from water samples [58]. In their study, the synthesis of poly(ethylene glycol)-grafted silica nanoparticles was carried out by using sol gel technique and used for the preparation of high-density polyethylene nanocomposite membranes by using thermally induced phase-separation technique. The prepared silica nanoparticle-based polyethylene membranes efficiently removed humic acid from water samples. The prepared nanocomposite membranes also exhibited great water flux behavior, which is B7.45 times higher than the polyethylene membranes without silica nanoparticles.

Figure 7.5 The schematic demonstration of the removal of target dye compounds using chitosan-based nanocomposite membranes having cellulose nanocrystals (A) nanocomposite membrane, (B) methyl violet 2B removal from water samples, (C) rhodamine 6G removal from water samples, and (D) Victoria 2B removal from water samples. Source: Reproduced with permission from Z. Karim, A.P. Mathewa, M. Grahn, J. Mouzon, K. Oksman, Nanoporous membranes with cellulose nanocrystals as functional entity in chitosan: removal of dyes from water, Carbohydr. Polym. 112 (2014) 668 676.

Membrane applications of nanomaterials

169

Karim and colleagues developed chitosan-based nanocomposite membranes having cellulose nanocrystals for the efficient removal of various dye compounds such as methyl violet 2B, victoria blue 2B, and rhodamine 6G from water samples [59]. For this purpose, cellulose nanocrystals were embedded into the polymeric structure of chitosan. The chitosan-based nanocomposite membranes effectively removed the target dye compounds from water samples (Fig. 7.5). The achieved removal efficiencies of rhodamine 6G, methyl violet 2B, and Victoria blue 2B were 70%, 84%, and 98%, respectively.

7.5

Molecularly imprinted polymer-based membranes

MIPs are tailor-made materials having specific binding sites toward the desired compound [60 63]. MIPs are prepared by polymerization of appropriate functional monomers in the presence of a cross-linker and the desired compound also called “template” (Fig. 7.6). The design and preparation of novel membranes that exhibit high selectivity and permeation behavior toward the target compound/s are still a crucial and challenging issue. The recent studies showed that the combination of membrane technology and molecular imprinting technology is an excellent approach for the development of composite membranes. These composite membranes can efficiently be applied for the separation of target compounds [65,66]. In an important research reported by Roy and coworkers [67], molecularly imprinted composite membranes bearing ZnS nanoparticles modified with cysteine functional groups were prepared for the removal of As31 and As51 ions from water

Figure 7.6 The schematic demonstration of the molecular imprinting technology. Source: Reproduced with permission from T. Kubo, K. Otsuka, Recent progress for the selective pharmaceutical analyses using molecularly imprinted adsorbents and their related techniques: a review, J. Pharm. Biomed. Anal. 130 (2016) 68 80.

170

Handbook of Nanomaterials in Analytical Chemistry

samples. The obtained results confirmed that the prepared MIP-based nanocomposite membranes exhibited excellent removal behavior toward the target ions. The highest removal capacity values of the composite membrane for the target ions As31 and As51 were found as 151 and 130 mg g21, respectively. Zhu et al. developed an electrochemical sensor having MIP-based magnetic nanocomposite membrane for the sensitive recognition of glutathione in blood samples [68]. For this purpose, they first synthesized magnetic polyaniline (Fe3O4@PANI) and incorporated into the RGO layers as schematically demonstrated in Fig. 7.7. After preassembly step in the presence of template compound glutathione, electropolymerization was carried out on the surface of glassy carbon electrode. The prepared MIP-based magnetic nanocomposite membrane was characterized by using SEM, AFM, cyclic voltammetry, and EDS. The obtaned results indicated that the prepared electrochemical sensor exhibited great response toward glutathione in blood samples with a detection limit of 3 nmol L21.

Figure 7.7 The fabrication of electrochemical sensor having MIP-based magnetic composite membrane. Source: Reproduced with permission from W. Zhu, G. Jiang, L. Xu, B. Li, Q. Cai, H. Jiang, et al., Facile and controllable one-step fabrication of molecularly imprinted polymer membrane by magnetic field directed self-assembly for electrochemical sensing of glutathione, Anal. Chim. Acta 886 (2015) 37 47.

Membrane applications of nanomaterials

171

In another study [69], Gao and colleagues developed MWCNTs/MIP-based nanocomposite membranes for the efficient separation of enoxacin from wastewater samples. In their study, MWCNTs were first modified with pDA and then the target compound enoxacin was imprinted into the pDA/MWCNTs structure. In the final step, pDA/MWCNTs/polyvinylidene fluoride membrane was prepared by using immersion phase-inversion technique. Fig. 7.8 shows the schematic demonstration of the preparation of MWCNT-based enoxacin-imprinted nanocomposite membrane. The results showed that the prepared MWCNTs/MIP-based nanocomposite membrane displayed great removal performance toward the target compound enoxacin from wastewater samples. The binding capacity of the imprinted membranes for enoxacin was achieved as 31.56 mg g21. Lu and colleagues developed thermosensitive GO-based ion-imprinted nanocomposite membranes for the selective separation of Eu31 ions [70]. The grafting of silver nanoparticles on the surface of nanocomposite membranes to enhance the antifouling feature was also carried out. Thermosensitive recognition and binding sites of the imprinted membranes were created by using functional monomers acrylamide and N-isopropylacrylamide. The prepared GO-based ion-imprinted nanocomposite membranes were successfully applied for the selective separation of

Figure 7.8 The schematic demonstration of the preparation of MWCNT-based enoxacinimprinted nanocomposite membrane. Source: Reproduced with permission from J. Gao, Y. Wu, J. Cui, X. Wu, M. Meng, C. Li, et al., Bioinspired synthesis of multi-walled carbon nanotubes based enoxacin-imprinted nanocomposite membranes with excellent antifouling and selective separation properties, J. Taiwan Inst. Chem. Eng. 2018 (in press).

172

Handbook of Nanomaterials in Analytical Chemistry

Eu31 ions in the existence of Gd31, La31, and Sm31. The binding capacity of the prepared GO-based ion-imprinted nanocomposite membranes toward Eu31 ions was obtained as 101.14 mg g21. In another interesting research conducted by Zhao et al. [71], MIP-based GO/ polyvinylidene fluoride nanocomposite membranes toward norfloxacin were prepared. Titaniumdioxide nanoparticles were embedded into the nanocomposite membrane structure to improve the antifouling feature of the membrane. The schematic depiction of the selective binding performance of the imprinted GO/polyvinylidene fluoride nanocomposite membrane toward norfloxacin is shown in Fig. 7.9. The results showed that the prepared imprinted nanocomposite membrane exhibited great affinity and selectivity for the target compound norfloxacin. The maximum norfloxacin binding capacity was achieved as 44.81 mg g21. Some recent studies on the applications of nanomaterial-based composite membranes are given in Table 7.1.

Figure 7.9 The schematic depiction of the selective binding performance of the imprinted GO/polyvinylidene fluoride nanocomposite membrane toward norfloxacin. Source: Reproduced with permission from J. Zhao, Y. Wu, S. Zhou, L. Yan, H. Dong, L. Chen, et al., Molecularly imprinted nanocomposite membranes based on GO/PVDF blended membranes with an organic-inorganic structure for selective separation of norfloxacin, New J. Chem. 41 (2017) 14966 14976.

Membrane applications of nanomaterials

173

Table 7.1 Recent applications of nanomaterial-based composite membranes. Composition of nanomaterial-based membranes

Target compound

Sample

Reference

MWCNT modified with Fe and Ag nanoparticles/ polyether sulfone nanocomposite membrane CNT/polyvinyl alcohol composite membrane MWCNT/graphene oxidebased nanocomposite membrane MWCNT modified with tetraethylene pentamine/ polyurethane nanocomposite membrane SiO2 nanoparticle/MIPbased nanocomposite membrane MIP-based nanomembrane using nylon 6 MIP/CNT-based nanocomposite membrane Magnetic Fe3O4 nanoparticles/ polyvinylidene fluoride nanocomposite membrane Polyaniline/graphene oxide nanoparticle-based nanocomposite membrane Zinc oxide/graphene oxide nanoparticle-based nanocomposite membrane MIP/graphene oxide nanoparticle-based nanocomposite membrane Magnetic Fe3O4 nanoparticles/chitosan/ polyvinyl alcohol nanofiber-based polyethersulfone nanocomposite membrane MIP nanofiber membrane MIP-based polysulfone nanocomposite membrane

Cr(VI)

Water

[72]

Oil

Wastewater

[73]

Acid red B, methyl blue, and light blue A

Water

[74]

CO2/CH4

Gas

[75]

Ferulic acid

Water

[76]

Acesulfame

[77]

Sodium chloride

Beverage samples Beverage samples Water

Pb(II)

Water

[80]

Sodium chloride and sodium sulfate

Water

[81]

Polycyclic aromatic hydrocarbons

Water

[82]

Pb(II) and Cr(VI)

Water

[83]

Bisphenol A Paclitaxel

Wastewater Plant extract

[84] [85]

Tartrazine

[78] [79]

(Continued)

174

Handbook of Nanomaterials in Analytical Chemistry

Table 7.1 (Continued) Composition of nanomaterial-based membranes

Target compound

Sample

Reference

MIP/TiO2 nanoparticlebased polysulfone nanocomposite membrane MIP-based polyvinylidene fluoride nanocomposite membrane Zinc oxide nanoparticles/1butyl-3methylimidazolium tetrafluoroborate nanocomposite membrane MIP-based alumina nanocomposite membrane

Methyl orange and methylene blue

Water

[86]

Artemisinin

Water

[87]

CO2

Gas

[88]

Phenol

[89]

MWCNT-based polysulfone hollow fiber nanocomposite membrane Graphene oxide-based polyamide nanocomposite membrane Graphene oxide/ polyethylene imine nanocomposite membrane MWCNT-based and carbon fiber-based ethyleneoctene nanocomposite membranes

Humic acid and procion red

Salicylic acid effluent Water

Sodium chloride and sodium sulfate

Water

[91]

Phenanthrene, bovine serum albumin and lysozyme Helium, oxygen, hydrogen, nitrogen, methane, and carbon dioxide for the gas-separation studies Toluene, hexane, and ethanol for the vaporseparation studies Water vapor

Water

[92]

Gas and water

[93]

Water

[94]

Cr(VI)

Water

[95]

Bisphenol A

Water

[96]

Graphene oxide/polyether block amide (Pebax1657) nanocomposite membrane TiO2 nanoparticle-based polysulfone nanocomposite membrane TiO2 nanoparticle-based polysulfone nanocomposite membrane doped with Fe

[90]

(Continued)

Membrane applications of nanomaterials

175

Table 7.1 (Continued) Composition of nanomaterial-based membranes

Target compound

Sample

Reference

Fluorinated-TiO2 nanoparticle-based polyvinylidene fluoride nanocomposite hollow fiber membrane Nano silica-based ceramic membrane TiO2 nanoparticle-based polyvinylidene difluoride and polyacrylonitrile nanocomposite membranes TiO2 nanoparticle-based polysulfone nanocomposite membrane TiO2/ZrO2-based ceramic nanocomposite membranes

CO2

Gas liquid

[97]

Methylene blue

[98]

Phage F2 as the model virus

Aqueous solutions Drinking water

Eosin yellow

Water

[100]

NaCl, CaCl2, MgCl2, and Na2SO4

Water

[101]

7.6

[99]

Conclusions and future trends

The increasing number of research, in which membrane technology based on nanomaterials was applied for the separation processes, showed that these nanocomposite materials can be efficiently used for the selective separation of target compound/s from environmental samples. The demonstrated examples in this chapter highlight the recent progresses in the design and fabrication of composite membranes on the basis of nanomaterials such as graphenes, fullerenes, carbon nanotubes, and nanoparticles. The combination of membranes with the unique features of nanomaterials provides great physical and chemical stability and also high rejection toward the target compound to be separated from the sample. In addition, the combination of nanotechnology with the membrane technology provides new ways to design and fabrication of novel nanocomposite membrane platforms in many application areas. In spite of the many succesful examples of nanomaterial-based composite membranes in the literature, the technologies applied for the fabrication of nanomaterialincorporated membrane platforms are still under development and more efforts are needed to produce low-cost, efficient, selective, and reusable membrane platforms before these nanocomposite membrane platforms are commercially available in the market.

176

Handbook of Nanomaterials in Analytical Chemistry

References [1] Y. Lan, K. Groenen-Serrano, C. Coetsier, C. Causserand, Nanofiltration performances after membrane bioreactor for hospital wastewater treatment: Fouling mechanisms and the quantitative link between stable fluxes and the water matrix, Water Res. (2018) (In press). [2] B.-J. Shi, Y. Wang, Y.-K. Geng, R.-D. Liu, X.-R. Pan, W.-W. Li, et al., Application of membrane bioreactor for sulfamethazine-contained wastewater treatment, Chemosphere 193 (2018) 840 846. [3] R. Ben-Mansour, H. Li, M.A. Habib, Thin film membrane for CO2 separation with sweeping gas method, Energy 144 (2018) 619 626. [4] M.B. Karimi, G. Khanbabaei, G.M.M. Sadeghi, Vegetable oil-based polyurethane membrane for gas separation, J. Membr. Sci. 527 (2017) 198 206. [5] M.S. AlQahtani, K. Mezghani, Thermally rearranged polypyrrolone membranes for high-pressure natural gas separation applications, J. Nat. Gas Sci. Eng. 51 (2018) 262 270. [6] J.B. James, Y.S. Lin, Thermal stability of ZIF-8 membranes for gas separations, J. Membr. Sci. 532 (2017) 9 19. [7] P.S. Goh, A.F. Ismail, A review on inorganic membranes for desalination and wastewater treatment, Desalination 434 (2018) 60 80. [8] M. Shokri Doodeji, M.M. Zerafat, M.H. Yousefi, S. Sabbaghi, Effect of OH-treatment of PDMS on rejection in hybrid nanofiltration membranes for desalination, Desalination 426 (2018) 60 68. [9] P. Chen, X. Ma, Z. Zhong, F. Zhang, W. Xing, Y. Fan, Performance of ceramic nanofiltration membrane for desalination of dye solutions containing NaCl and Na2SO4, Desalination 404 (2017) 102 111. [10] A. Kubaczka, Prediction of Maxwell Stefan diffusion coefficients in polymer multicomponent fluid systems, J. Memb. Sci. 470 (2014) 389 398. [11] M. Ahmadi, H. Elmongy, T. Madrakian, M. Abdel-Rehim, Nanomaterials as sorbents for sample preparation in bioanalysis: A review, Anal. Chim. Acta 958 (2017) 1 21. [12] C.M. Hussain, Magnetic nanomaterials for environmental analysis, in: C.M. Hussain, B. Kharisov (Eds.), Advanced Environmental Analysis-Application of Nanomaterials, The Royal Society of Chemistry, London, UK, 2017. [13] R. Kec¸ili, C.M. Hussain, Recent progress of ımprinted nanomaterials in analytical chemistry, Int. J. Anal. Chem. (2018). Article ID8503853. [14] S. Bu¨yu¨ktiryaki, Y. Su¨mbelli, R. Kec¸ili, C.M. Hussain, Lab-on-chip platforms for environmental analysis, in: Paul Worsfold, Colin Poole, Alan Townshend, Manuel Miro´ (Eds.), Encyclopedia of Analytical Science, Third Edition, Academic Press, Cambridge, Massachusetts, USA, 2019, pp. 267 273. [15] R. Kec¸ili, S. Bu¨yu¨ktiryaki, C.M. Hussain, Advancement in bioanalytical science through nanotechnology: past, present and future, TrAC Trend Anal. Chem. 110 (2019) 259 276. [16] S. Vercauteren, K. Keizer, E. Vansant, J. Luyten, R. Leysen, Porous ceramic membranes: preparation, transport properties and applications, J. Porous Mater. 5 (1988) 241 258. [17] R. Sondhi, R. Bhave, G. Jung, Applications and benefits of ceramic membranes, Membr. Technol. 2003 (11) (2003) 5 8.

Membrane applications of nanomaterials

177

[18] R.S. Faibish, Y. Cohen, Fouling-resistant ceramic-supported polymer membranes for ultrafiltration of oil-in-water microemulsions, J. Membr. Sci. 185 (2001) 129 143. [19] T. Tsuru, Nano/subnano-tuning of porous ceramic membranes for molecular separation, J. Sol-Gel Sci. Technol. 46 (2008) 349 361. [20] P. Wu, Y.Z. Xu, Z.X. Huang, J.C. Zhang, A review of preparation techniques of porous ceramic membranes, J. Ceram. Process Res. 16 (2015) 102 106. [21] M.M. Pendergast, E.M.V. Hoek, A review of water treatment membrane nanotechnologies, Energ. Environ. Sci. 4 (2011) 1946 1971. [22] A.P. Rao, N. Desai, R. Rangarajan, Interfacially synthesized thin film composite RO membranes for sea water desalination, J. Membr. Sci. 124 (1997) 263 272. [23] M.S. Oak, T. Kobayashi, H.Y. Wang, T. Fukaya, N. Fujii, pH effect on molecular size exclusion of polyacrylonitrile ultrafiltration membranes having carboxylic acid groups, J. Membr. Sci. 123 (1997) 185 195. [24] K. Goh, H.E. Karahan, L. Wei, T.-H. Bae, A.G. Fane, R. Wang, et al., Carbon nanomaterials for advancing separation membranes: a strategic perspective, Carbon 109 (2016) 694 710. [25] S. Liu, T.H. Zeng, M. Hofmann, E. Burcombe, J. Wei, R. Jiang, et al., Antibacterial activity of graphite, graphite oxide, graphene oxide, and reduced graphene oxide: membrane and oxidative stress, ACS Nano 5 (9) (2011) 6971 6980. [26] Q. Zhang, X. Fan, H. Wang, S. Chen, X. Quan, Fabrication of Au/CNT hollow fiber membrane for 4-nitrophenol reduction, RSC Adv. 6 (2016) 41114 41121. [27] K.S. Novoselov, A.K. Geim, S.V. Morozov, D. Jiang, Y. Zhang, S.V Dubonos, I.V. Grigorieva, A.A. Firsov, Electric field effect in atomically thin carbon films, Science 306 (2004) 666 669. [28] K. Jayaramulu, K.K.R. Datta, C. Ro¨sler, M. Petr, M. Otyepka, R. Zboril, et al., Biomimetic superhydrophobic/superoleophilic highly fluorinated graphene oxide and ZIF-8 composites for oil-water separation, Angew Chem. Int. Ed. 55 (3) (2016) 1178 1182. [29] B. Li, X. Liu, X. Zhang, J. Zou, W. Chai, J. Xu, Oil-absorbent polyurethane sponge coated with KH-570-modified graphene, J. Appl. Polym. Sci. 132 (16) (2015) 41821 41828. [30] N.L. Le, P.H.H. Duong, S.P. Nunes, Advanced polymeric and organic_inorganic membranes for pressuredriven processes, Reference Module in Chemistry, Molecular Sciences and Chemical Engineering., Elsevier, Amsterdam, Netherlands, 2017. [31] J.A. Prince, S. Bhuvana, V. Anbharasi, N. Ayyanar, K.V.K. Boodhoo, G. Singh, Ultrawetting graphene-based PES ultrafiltration membrane-a novel approach for successful oil-water separation, Water Res. 103 (2016) 311 318. [32] S. Nasseri, S. Ebrahimi, M. Abtahi, R. Saeedi, Synthesis and characterization of polysulfone/graphene oxide nanocomposite membranes for removal of bisphenol A from water, J. Environ. Manage. 205 (2018) 174 182. [33] J. Zhang, Q. Xue, X. Pan, Y. Jin, W. Lu, D. Ding, et al., Graphene oxide/polyacrylonitrile fiber hierarchical-structured membrane for ultra-fast microfiltration of oil-water emulsion, Chem. Eng. J. 307 (2017) 643 649. [34] L. Zhu, H. Wang, J. Bai, J. Liu, Y. Zhang, A porous graphene composite membrane intercalated by halloysite nanotubes for efficient dye desalination, Desalination 420 (2017) 145 157. [35] X. Hu, Y. Yu, J. Zhou, Y. Wang, J. Liang, X. Zhang, et al., The improved oil/water separation performance of graphene oxide modified Al2O3 microfiltration membrane, J. Membr. Sci. 476 (2015) 200 204.

178

Handbook of Nanomaterials in Analytical Chemistry

[36] K.C. Ho, Y.H. Teow, W.L. Ang, A.W. Mohammad, Novel GO/OMWCNTs mixedmatrix membrane with enhanced antifouling property for palm oil mill effluent treatment, Sep. Purif. Technol. 177 (2017) 337 349. [37] S. Iijima, Helical microtubules of graphitic carbon, Nature 354 (1991) 56 58. [38] L. Zhang, J. Gu, L. Song, L. Chen, Y. Huang, J. Zhang, et al., Underwater superoleophobic carbon nanotubes/core-shell polystyrene@Au nanoparticles composite membrane for flow-through catalytic decomposition and oil/water separation, J. Mater. Chem. A 4 (28) (2016) 10810 10815. [39] L. Bai, N. Bossa, F. Qu, J. Winglee, G. Li, K. Sun, et al., Comparison of hydrophilicity and mechanical properties of nanocomposite membranes with cellulose nanocrystals and carbon nanotubes, Environ. Sci. Technol. 51 (1) (2017) 253 262. [40] M. Sarno, A. Tamburrano, L. Arurault, S. Fontorbes, R. Pantani, L. Datas, et al., Electrical conductivity of carbon nanotubes grown inside a mesoporous anodic aluminium oxide membrane, Carbon 55 (2013) 10 22. [41] M. Namasivayam, J. Shapter, Factors affecting carbon nanotube fillers towards enhancement of thermal conductivity in polymer nanocomposites: a review, J Compos. Mater. 51 (26) (2017) 3657 3668. [42] L. Zhang, Y. Lu, Y.-L. Liu, M. Li, H.-Y. Zhao, L.-A. Hou, High flux MWCNTsinterlinked GO hybrid membranes survived incross-flow filtration for the treatment of strontium-containing wastewater, J. Hazard. Mater. 320 (2016) 187 193. [43] M.R. Mahdavi, M. Delnavaz, V. Vatanpour, Fabrication and water desalination performance of piperazine polyamide nanocomposite nanofiltration membranes embedded with raw and oxidized MWCNTs, J. Taiwan Inst. Chem. Eng. 75 (2017) 189 198. [44] B. Hudaib, V. Gomes, J. Shi, C. Zhou, Z. Liu, Poly (vinylidene fluoride)/polyaniline/ MWCNT nanocomposite ultrafiltration membrane for natural organic matter removal, Sep. Purif. Technol. 190 (2018) 143 155. [45] H.K. Shahzad, M.A. Hussein, F. Patel, N. Al-Aqeeli, M.A. Atieh, T. Laoui, Synthesis and characterization of alumina-CNT membrane for cadmium removal from aqueous solution, Ceram. Int. 44 (14) (2018) 17189 17198. [46] J. Saadati, M. Pakizeh, Separation of oil/water emulsion using a new PSf/pebax/FMWCNT nanocomposite membrane, J Taiwan Inst. Chem. Eng. 71 (2017) 265 276. [47] J. Gu, P. Xiao, L. Zhang, W. Lu, G. Zhang, Y. Huang, et al., Construction of superhydrophilic and underwater superoleophobic carbon-based membranes for water purification, RSC Adv. 6 (77) (2016) 73399 73403. [48] S. Maphutha, K. Moothi, M. Meyyappan, S.E. Iyuke, A carbon nanotube-infused polysulfone membrane with polyvinyl alcohol layer for treating oil-containing waste water, Sci. Report. 3 (2013) 1509. [49] J. Gu, P. Xiao, J. Chen, F. Liu, Y. Huang, G. Li, et al., Robust preparation of superhydrophobic polymer/carbon nanotube hybrid membranes for highly effective removal of oils and separation of water-in-oilemulsions, J. Mater. Chem. A 2 (37) (2014) 15268 15272. [50] R.K. Thines, N.M. Mubarak, S. Nizamuddin, J.N. Sahu, E.C. Abdullah, P. Ganesan, Application potential of carbon nanomaterials in water and wastewater treatment: a review, J. Taiwan Inst. Chem. Eng. 72 (2017) 116 133. [51] H. Wang, R. DeSousa, J. Gasa, K. Tasaki, G. Stucky, B. Jousselme, et al., Fabrication of new fullerene composite membranes and their application in proton exchange membrane fuel cells, J. Memb. Sci. 289 (2007) 277 283.

Membrane applications of nanomaterials

179

[52] G.-E. Chen, W.-W. Zhu, S.-J. Xu, Z.-L. Xu, Q. Shen, W.-G. Sun, et al., A PVDF/PVB composite UF membrane improved by F-127-wrapped fullerene for protein waste-water separation, RSC Adv. 6 (2016) 83510 83519. [53] S.S. Rikame, A.A. Mungray, A.K. Mungray, Synthesis, characterization and application of phosphorylated fullerene/sulfonated polyvinyl alcohol (PFSP) composite cation exchange membrane for copper removal, Sep. Purif. Technol. 177 (2017) 29 39. [54] X. Jin, J.Y. Hu, M.L. Tint, S.L. Ong, Y. Biryulin, G. Polotskaya, Estrogenic compounds removal by fullerene-containing membranes, Desalination 214 (2007) 83 90. [55] S. Saga, H. Matsumoto, K. Saito, M. Minagawa, A. Tanioka, Polyelectrolyte membranes based on hydrocarbon polymer containing fullerene, J. Power Sources 176 (2008) 16 22. [56] Y. Yu, L. Yu, C. Wang, J.P. Chen, An innovative yttrium nanoparticles/PVA modified PSF membrane aiming at decontamination of arsenate, J. Colloid Interface Sci. 530 (2018) 658 666. [57] Y. Lv, Y. Du, Z.-X. Chen, W.-Z. Qiu, Z.K. Xu, Nanocomposite membranes of polydopamine/electropositive nanoparticles/polyethyleneimine for nanofiltration, J. Memb. Sci. 545 (2018) 99 106. [58] A. Akbari, R. Yegani, B. Pourabbas, A. Behboudi, Fabrication and study of fouling characteristics of HDPE/PEG grafted silica nanoparticles composite membrane for filtration of humic acid, Chem. Eng. Res. Des. 109 (2016) 282 296. [59] Z. Karim, A.P. Mathewa, M. Grahn, J. Mouzon, K. Oksman, Nanoporous membranes with cellulose nanocrystals as functional entity in chitosan: removal of dyes from water, Carbohydr. Polym. 112 (2014) 668 676. [60] R. Kec¸ili, Selective recognition of myoglobin in biological samples using molecularly imprinted polymer-based affinity traps, Int. J. Anal. Chem. (2018). Article ID: 4359892. [61] J. Kupai, M. Razali, S. Bu¨yu¨ktiryaki, R. Kec¸ili, G. Szekely, Long-term stability and reusability of molecularly imprinted polymers, Polym. Chem 8 (2017) 666 673. [62] S. Emir Diltemiz, R. Kec¸ili, A. Erso¨z, R. Say, Molecular imprinting technology in quartz crystal microbalance (QCM) sensors, Sensors 17 (3) (2017) 454. ¨ zcan, A. Erso¨z, D. Hu¨r, A. Denizli, R. Say, Superparamagnetic [63] R. Kec¸ili, A. Atilir O nanotraps containing MIP based mimic lipase for biotransformations uses, J. Nanopart. Res. 13 (5) (2011) 2073 2079. [64] T. Kubo, K. Otsuka, Recent progress for the selective pharmaceutical analyses using molecularly imprinted adsorbents and their related techniques: a review, J. Pharm. Biomed. Anal. 130 (2016) 68 80. [65] Y.L. Wu, M.J. Meng, X.L. Liu, C.X. Li, M. Zhang, Y.J. Ji, et al., Efficient one-pot synthesis of artemisinin-imprinted membrane by direct surface-initiated AGET-ATRP, Sep. Purif. Technol. 131 (2014) 117 125. [66] Y.L. Wu, M. Yan, Y.S. Yan, X.L. Liu, M.J. Meng, P. Lv, et al., Fabrication and Evaluation of artemisinin-ımprinted composite membranes by developing a surface functional monomer-directing prepolymerization system, Langmuir 30 (2014) 14789 14796. [67] E. Roy, S. Patra, R. Madhuri, P.K. Sharma, A single solution for arsenite and arsenate removal from drinking water using cysteine@ZnS:TiO2 nanoparticle modified molecularly imprinted biofouling-resistant filtration membrane, Chem. Eng. J. 304 (2016) 259 270. [68] W. Zhu, G. Jiang, L. Xu, B. Li, Q. Cai, H. Jiang, et al., Facile and controllable onestep fabrication of molecularly imprinted polymer membrane by magnetic field directed

180

[69]

[70]

[71]

[72]

[73]

[74]

[75]

[76]

[77]

[78]

[79]

[80]

[81]

[82]

Handbook of Nanomaterials in Analytical Chemistry

self-assembly for electrochemical sensing of glutathione, Anal. Chim. Acta 886 (2015) 37 47. J. Gao, Y. Wu, J. Cui, X. Wu, M. Meng, C. Li, et al., Bioinspired synthesis of multiwalled carbon nanotubes based enoxacin-imprinted nanocomposite membranes with excellent antifouling and selective separation properties, J. Taiwan Inst. Chem. Eng. (2018) (In press). J. Lu, Y. Wu, X. Lin, J. Gao, H. Dong, L. Chen, et al., Anti-fouling and thermosensitive ion-imprinted nanocomposite membranes based on grapheme oxide and silicon dioxide for selectively separating europium ions, J. Hazard. Mater. 353 (2018) 244 253. J. Zhao, Y. Wu, S. Zhou, L. Yan, H. Dong, L. Chen, et al., Molecularly imprinted nanocomposite membranes based on GO/PVDF blended membranes with an organicinorganic structure for selective separation of norfloxacin, New J. Chem. 41 (2017) 14966 14976. M.L. Masheane, L.N. Nthunya, S.P. Malinga, E.N. Nxumalo, B.B. Mamba, S.D. Mhlanga, Synthesis of Fe-Ag/f-MWCNT/PES nanostructured-hybrid membranes for removal of Cr(VI) from water, Sep. Purif. Technol. 184 (2017) 79 87. G. Yi, S. Chen, X. Quan, G. Wei, X. Fan, H. Yu, Enhanced separation performance of carbon nanotube polyvinyl alcohol composite membranes for emulsified oily wastewater treatment under electrical assistance, Sep. Purif. Technol. 197 (2018) 107 115. H. Kang, J. Shi, L. Liu, M. Shan, Z. Xu, N. Li, et al., Sandwich morphology and superior dye-removal performances for nanofiltration membranes self-assemblied via graphene oxide and carbon nanotubes, Appl. Surf. Sci. 428 (2018) 990 999. K.M. Gheimasi, O. Bakhtiaria, M. Ahmadi, Preparation and characterization of MWCNT-TEPA/polyurethane nanocompositemembranes for CO2/CH4separation: Experimentaland modeling, Chem. Eng. Res. Des. 133 (2018) 222 234. M.H. Wei, H.-Y. Chen, S. Wang, W.-Y. Jiang, Y. Wang, Z.-F. Wu, Synthesis and characterization of hybrid molecularly imprinted membrane with blending SiO2 nanoparticles for ferulic acid, J. Inorg. Organomet. Polym. 27 (2017) 586 597. M.M. Moein, M. Javanbakht, M. Karimi, B. Akbari-Adergani, Fabrication of a novel electrospun molecularly imprinted nanomembrane coupled with high-performance liquid chromatography for the selective separation and determination of acesulfame, J. Sep. Sci. 38 (2015) 1372 1379. S. Yaripour, A. Mohammadi, S. Nojavan, Electromembrane extraction of tartrazine from food samples: Effects of nano-sorbents on membrane performance, J. Sep. Sci. 39 (2016) 2642 2651. T.A. Agbaje, S. Al-Gharabli, M.O. Mavukkandy, J. Kujawa, H.A. Arafat, PVDF/magnetite blend membranes for enhanced flux and salt rejection in membrane distillation, Desalination 436 (2018) 69 80. N. Ghaemi, S. Zereshki, S. Heidari, Removal of lead ions from water using PES based nanocomposite membrane incorporated with polyaniline modified GO nanoparticles: performance optimization by central composite design, Process Saf. Environ. Prot. 111 (2017) 475 490. A. Al Mayyahi, Thin-film composite (TFC) membrane modified by hybrid ZnOgraphene nanoparticles (ZnO-Gr NPs) for water desalination, J. Environ. Chem. Eng. 6 (2018) 1109 1117. R.W. Kibechu, D.T. Ndinteh, T.A.M. Msagati, B.B. Mamba, S. Sampath, Effect of incorporating graphene oxide and surface imprinting on polysulfone membranes on

Membrane applications of nanomaterials

[83]

[84]

[85]

[86]

[87]

[88]

[89]

[90]

[91]

[92]

[93]

[94] [95]

[96]

[97]

181

flux, hydrophilicity and rejection of salt and polycyclic aromatic hydrocarbons from water, Phys. Chem. Earth 100 (2017) 126 134. S. Koushkbaghi, A. Zakialamdari, M. Pishnamazi, H.F. Ramandi, M. Aliabadi, M. Irani, Aminated-Fe3O4 nanoparticles filled chitosan/PVA/PES dual layers nanofibrous membrane for the removal of Cr(VI) and Pb(II) ions from aqueous solutions in adsorption and membrane processes, Chem. Eng. J. 337 (2018) 169 182. F. Liu, Q. Liu, Y. Zhang, Y. Liu, Y. Wan, K. Gao, et al., Molecularly imprinted nanofiber membranes enhanced biodegradation of trace bisphenol A by Pseudomonas aeruginosa, Chem. Eng. J. 262 (2015) 989 998. S. Ghasemi, A. Nematollahzadeh, Molecularly imprinted ultrafiltration polysulfone membrane with specificnano-cavities for selective separation and enrichment of paclitaxel from plant extract, React. Funct. Polym. 126 (2018) 9 19. H.K. Melvin, C.P. Leo, A.Z. Abdullah, Selective removal of dyes by molecular imprinted TiO2 nanoparticles in polysulfone ultrafiltration membrane, J. Environ. Chem. Eng. 5 (2017) 3991 3998. J. Cui, Y. Wu, M. Meng, J. Lu, C. Wang, J. Zhao, et al., Bio-inspired synthesis of molecularly imprinted nanocomposite membrane for selective recognition and separation of artemisinin, J. Appl. Polym. Sci. 103 (2016) 43405. K.W. Yoon, H. Kim, Y.S. Kang, S.W. Kang, 1-Butyl-3-methylimidazolium tetrafluoroborate/zinc oxide composite membrane for high CO2 separation performance, Chem. Eng. J. 320 (2017) 50 54. Y. Liu, M. Meng, J. Yao, Z. Da, Y. Feng, Y. Yan, et al., Selective separation of phenol from salicylic acid effluent over molecularly imprinted polystyrene nanospheres composite alumina membranes, Chem. Eng. J. 286 (2016) 622 631. J. Yin, G. Zhu, B. Deng, Multi-walled carbon nanotubes (MWNTs)/polysulfone (PSU) mixed matrix hollow fiber membranes for enhanced water treatment, J. Memb. Sci. 437 (2013) 237 248. J. Yin, G. Zhu, B. Deng, Graphene oxide (GO) enhanced polyamide (PA) thin-film nanocomposite (TFN) membrane for water purification, Desalination 379 (2016) 93 101. L. Zhang, B. Chen, A. Ghaffar, X. Zhu, Nanocomposite membrane with polyethylenimine-grafted graphene oxide as a novel additive to enhance pollutant filtration performance, Environ. Sci. Technol. 52 (2018) 5920 5930. Z. Sedla´kova´, G. Clarizia, P. Bernardo, J.C. Jansen, P. Slobodian, P. Svoboda, et al., Carbon nanotube- and carbon fiber-reinforcement of ethylene-octene copolymer membranes for gas and vapor separation, Membranes 4 (2014) 20 39. F.H. Akhtar, M. Kumar, K.V. Peinemann, Pebaxs1657/Graphene oxide composite membranes for improved water vapor separation, J. Memb. Sci. 525 (2017) 187 194. M.S. Jyothi, V. Nayak, M. Padaki, R. Geetha Balakrishna, K. Soontarapa, Aminated polysulfone/TiO2 composite membranes for an effective removal of Cr(VI), Chem. Eng. J. 283 (2016) 1494 1505. Q. Wang, C. Yang, G. Zhang, L. Hu, P. Wang, Photocatalytic Fe-doped TiO2/PSF composite UF membranes: characterization and performance on BPA removal under visible-light irradiation, Chem. Eng. J. 319 (2017) 39 47. Y. Lin, Y. Xu, C.H. Loh, R. Wang, Development of robust fluorinated TiO2/PVDF composite hollow fiber membrane for CO2 capture in gas-liquid membrane contactor, Appl. Surf. Sci. 436 (2018) 670 681.

182

Handbook of Nanomaterials in Analytical Chemistry

[98] G.M.K. Tolba, A.M. Bastaweesy, E.A. Ashour, W. Abdelmoez, K.A. Khalil, N.A.M. Barakat, Effective and highly recyclable ceramic membrane based on amorphous nanosilica for dye removal from the aqueous solutions, Arab. J. Chem. 9 (2016) 287 296. [99] Z. Xiang, C. Di, W. Zhiwei, L. Yang, C. Rong, Nano-TiO2 membrane adsorption reactor (MAR) for virus removal in drinking water, Chem. Eng. J. 230 (2013) 180 187. [100] A.T. Kuvarega, N. Khumalo, D. Dlamini, B.B. Mamba, Polysulfone/N, Pd co-doped TiO2 composite membranes for photocatalytic dye degradation, Sep. Purif. Technol. 191 (2018) 122 133. [101] H. Guo, S. Zhao, X. Wu, H. Qi, Fabrication and characterization of TiO2/ZrO2 ceramic membranes for nanofiltration, Micropor. Mesopor. Mater. 260 (2018) 125 131.

Micro total analysis systems with nanomaterials

8

Ru¨stem Kec¸ili1, Sibel Bu¨yu¨ktiryaki1 and Chaudhery Mustansar Hussain2 1 Yunus Emre Vocational School of Health Services, Department of Medical Services and Techniques, Anadolu University, Eski¸sehir, Turkey, 2Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, NJ, United States

8.1

Introduction

Micro total analysis systems (µTAS) can be defined as a miniature chemistry laboratory that is processing through specific reactions on a chip [1,2]. The roots of µTAS applications rely on the discovery of the techniques that provide a possibility for the experiments without the need of a fully functioning laboratory and usage of small amounts (from a few picoliters to a few tens of microliters) of reactants. µTAS combine several analytical steps including sampling, preparation, preconcentration, filtration, derivatization, reaction, isolation, and detection in a single chip of only millimeters to a few square centimeters in size with high-throughput analysis. Recently, µTAS-based devices have become very attractive because of the development of personalized devices for point-of-care (POC) testing. On the other hand, nanomaterials have gained great attention from many researchers, as they display unique properties such as high physical and chemical stability, versatile chemistry for the functionalization, and high surface area [3 5]. The progress of µTAS is related to the fabrication of integrated circuit systems that was invented by Kilby who is the Nobel Prize winner in Physics in 2000 [6]. After this invention, miniaturization and integration efforts have gained great importance in the design and development of electronic and nonelectronic devices. Miniaturization of analytical systems has a wide range of applications in microelectronics, chemistry, biology, physics, pharmaceutical, environmental, clinical diagnosis, and food analysis. Miniaturization reduces the process costs by decreasing the consumption of expensive chemicals and the sample by increasing throughput and automation and also reduces waste generation and energy consumption. The first demonstration of µTAS application on the preparation of silicon wafer that was used as a gas analysis system in terms of gas chromatography (GC) with a thermal conductivity detector was carried out by Terry and colleagues [7]. The system was prepared by applying photolithography technique and chemical etching, and it was consisted of a 1.5-m-long spiral capillary column and an injection valve on a 5-cm-diameter wafer. Being able to use the device as efficient as an oldfashioned and as a generally accepted GC device meant that the requirement of big equipment was cleared out. Although the system showed the possibility, researchers Handbook of Nanomaterials in Analytical Chemistry. DOI: https://doi.org/10.1016/B978-0-12-816699-4.00008-6 Copyright © 2020 Elsevier Inc. All rights reserved.

186

Handbook of Nanomaterials in Analytical Chemistry

were not very keen to use the technology until the beginning of 1990s when Manz and coworkers defined the miniaturized total chemical analysis systems [8]. According to Manz’s proposed µTAS term, the injection, separation, and detection systems were consisting in the same interface. This research was not only defining the µTAS, but it was also a realization at the same time for scientists to use the technique in life sciences. The produced systems were used for different applications since then, such as separation [9 11], detection [12 14], or used as a reactor [15 18].

8.2

The components of micro total analysis systems

Although µTAS may consist of a variety of units depending on the experimental setup, they all contain four main components (Fig. 8.1). G

G

G

G

Inlet unit: The unit where the sample(s) is/are injected into the system. Reactor unit: The unit where the reaction occurs (depending on the experimental setup, it may be a separation reaction, detection, screening, and cell culturing) Analyze unit: The unit where the results are collected by sensors. Data process unit: The unit where the results are converted into output signal.

Besides these units, there may be other components on the µTAS device like a conditioning unit for GC applications, amplification unit for polymerase chain reaction (PCR) applications or a valve unit when there is a need for simultaneous injection. µTAS devices may also contain valves, microfluidic mixers, microelectrodes, thermal elements, or optical apparatuses. Photolithography, soft lithography, micro manufacturing, ink-print technology, polymerization-based prototyping, hot embossing, microinjection molding, microcontact printing, microtransfer molding, micromilling, and 3D printing can be used

Figure 8.1 The components of a µTAS.

Micro total analysis systems with nanomaterials

187

for chip fabrication. Elastomeric materials such as poly[(3-mercaptopropyl)-methylsiloxane] can be efficiently used in soft lithography technique. A cutting tool is used for micro manufacturing, but this fabrication technique has a dissadvantage because of the size obtained from this method. A substrate and a patterned elastomeric master should be in contact in molding procedure. Polymerization-based fabrication and microtransfer molding techniques could create three dimensions and they are layer-by-layer fabrication techniques [19]. Silicon, glass, paper, polymers such as polymethyl methacrylate (PMMA), polyimide, polyethylene terephthalate, and polyethylene can be used as substrate materials for the fabrication µTAS. Poly(dimethylsiloxane) (PDMS) is the most widely used silicone-based organic polymer in the fabrication of µTAS. It has many advantages that are briefly described in the following points: G

G

G

G

PDMS is considered to be a biocompatible material within certain limits. Biocompatibility is a preferred feature in various applications where tissue and cells are used. It is easy to connect PDMS with different layers made of glass or the same material. This makes PDMS an advantage for different technological applications. It also allows for complex systems to be separated into simpler layers and easily combined. PDMS is a visco-elastic material. In other words, it behaves like a viscous liquid at high temperatures or when left alone for a long time. PDMS also covers the surface when left on its own in the same way. It is possible to fill the nanolevel gaps on the surface with PDMS. Therefore it is very easy to give the desired shape by using a mold compared to other materials. On the other hand, the PDMS behaves like an elastic solid in low temperatures or short-term contact with the surface like a rubber ball. It can be easily separated from the molds as it acts as an elastic layer. Owing to its gas permeability, it makes its use in miniature laboratory chips produced for cell culture applications. In addition, air bubbles that remain in the channels when the liquid is filled to be analyzed in the microchannels can be passed out through the PDMS.

On the other hand, glass is optical transparan, biocompatible, and chemical and thermal compatible material. Owing to its optical transparency, glass-based µTAS platforms can be efficiently used for the optical detection. In addition, the modification and functionalization of glass surface are easy and electro-osmotic flow occurs easily. Silicon has remarkable chemical resistance and good mechanical properties. When silicon is used, microfluidic channels are easly patterned. Some of polymers have optical transparency, for that reason its usage increases related analytical techniques and its molding flexibility is quite good for the fabrication of complex geometries. Polymers are also relativey cheap materials. Micromachining, hot embossing, 3D printing, soft lithography, and rapid prototyping could be used for polymer fabrication method. PDMS is a widely used polymer, because it is cheap, hydrophobic, clear elastomeric polymer and it is a combination of mechanical, optical, and electrical properties. Cyclic olefin copolymers are extensively used for µTAS substrate because of its unique properties of biocompatibility, high optical transparency, and very low cost. On the other hand, paper-based µTAS platforms also known as microfluidic paper-based analytical platforms (µPAD) are promising. Wax patterning, flexographic printing, shaping, and cutting can be used for the fabrication of µPAD [20].

188

Handbook of Nanomaterials in Analytical Chemistry

A µTAS platform contains microchannels and the liquid samples flow within the microchannel in the chip. µTAS operations can be combined in different flow types, such as pressure-driven flow, electroosmatic flow (EOF), lateral flow tests (capillary), centrifugal, and surface acoustic waves. Pressure-driven flow is the most widely used flow type. Syringe micropumps (piezoelectric, magnetohydrodynamic, or centrifugal) can control the liquid flow. Because pressure-driven flow has a parabolic velocity flow profile, sample plug dispersion, and peak-broadening occurs. For that reason, this method is less attractive for the separation application. Another widely used flow type is EOF that occurs by applying high voltage. The charged molecules are manipulated in the presence of electric field and a double layer of electric charge is occurred.

8.3

Advantages and disadvantages of micro total analysis systems

The advantages of µTAS concept can be explained in the following three main groups: G

G

G

Ease of use: One of the main downsides of using a specially equipped laboratory is the necessity of highly skilled personnel to be able to use the complex analysis apparatus. By using lab-on-a-chip concept, this problem was ruled out thanks to their user-friendly characteristics. Size: Before the discovery of µTAS concept, the samples themselves needed to be transferred to the laboratory for the sample analysis. Thanks to their small size, µTAS platforms are a perfect option to be used in field and spot-on analyze. The smaller diameter of the channel requires less consumption of sample, allows a better separation, and also shorter channel length allows shorter transport time or faster reaction times. Cost: The cost for the production of a µTAS platform cannot even be compared to the cost of an analyzer device in a laboratory. Small amounts of expensive reagents are used.

Because of these advantages of µTAS over the conventional approaches and devices, µTAS are highly preferred in many applications. However, the µTAS technology is still under development and there are still some problems to be solved in the fabrication steps (i.e., the material used for the device may have undesired effects on the sample which causes negative results for the analyses, the fabrication methods are generally not as precise as engineered devices).

8.4

Applications of micro total analysis systems

Since nearly all the chemical experiments and clinical test methods need detection and quantification of molecules, µTAS platforms are convenient for these fields. The need of rapid and cheap analysis techniques in order to be able to reach as many people as possible in clinical applications and the aim of reducing the cost of

Micro total analysis systems with nanomaterials

189

biotechnological applications were the main reasons why lab-on-a-chip applications were focused mostly on these subjects. Like pregnancy tests or blood glucose level tests, the easy-to-use characteristics and stability were two main alluring features of lab on a chip concept both for end-users and scientists. In addition, lab-on-a-chip devices are also being used in more specific experimental practices too, for example, cell culture, PCR applications, immunoassays, biomolecule purification, protein detection, and drug development. Besides of these, there is an exponential interest on POC testing and spot-on environmental monitoring by using µTAS platforms.

8.4.1 Analysis of environmental samples Starting from early millennium years, dealing with environmental problems (e.g., global warming, undrinkable dirty water, air pollution, and marine debris) has gained more and more importance. The need of small amount of sample and fast analysis possibility of µTAS platforms have made the spot-on analysis and simultaneous monitoring of environmental problems easier more than ever. As can be seen in Table 8.1, µTAS technology could be adopted with most analytical chemistry methods, such as thermal detection, ultrasound waves, mass spectrometry, electrochemical sensing, capillary electrophoresis, electrochromatography, and optical methods such as absorbance, fluorescence, infrared and Raman spectroscopy, scattering, refractive index, and surface plasmon resonance. In a reported study, researchers from the University of Cincinnati have succeeded in continuous heavy metal detection in environmental samples by using a µTAS [48]. The developed micromachined polycarbonate-based disposable chip was successfully used for the sensitive detection of Cd(II) ions in ground water samples and soil. In another study for water-quality testing, researchers developed a lab-on-a-disc device in order to monitor the pH and turbidity changes in samples [49]. By using a combination of poly- (methyl methacrylate) discs and pressuresensitive adhesive films, a multilayered disc structure is used as a lab-on-a-chip device. The possibility of in situ monitoring of pH and the degree of turbidity offers a new sight for POC optical detector applications. Apart from water monitoring, water purification studies by using µTAS concept have also gained interest in environmental monitoring applications. In 2012, a group of researchers from China and Switzerland developed a µTAS reactor that has solved the recombination of photo-excited electrons and holes problem in photocatalytic water purification applications [50]. The problem of oxygen deficiency was also eliminated under bias potential with water electrolysis by using the developed µTAS-based reactor. In a more end-user alluring way, Lee and Yang developed a smartphone-based µTAS [51]. The system used ambient illumination without the need of a dedicated light source and functioning as an imaging device for the mobile healthcare and environmental monitoring. Beside the health-related applications, the system was able to show various types of green algae in water samples. Although the system

Table 8.1 The recent examples of µTAS systems in environmental applications. Analyte

Material

Fabrication

Limit of detection (LOD)

Technique

Reference

Atrazine

PDMS microfluidic platforms, boron-doped diamond electrodes with platinum nanoparticles PDMS microchips

Photolithography

3.5 pM

Chronoamperometry

[21]

Photolithography

1.0 µM for AP, 0.6 µM for PCP, 0.7 µM for DNOC, 1.8 µM for NP, 1.2 µM for VA, 1.8 µM for HBA

Pulsed amperometry

[22]

Cyclic olefin copolymer, Ag/ AgCl electroplating for sensor chip

Photolithography microfabrication and screen-printing techniques Laser micromachined gaskets

9.3 ppb for Cd21 and 8 ppb for Pb21

Square-wave anodic stripping voltammetry

[23]

5 3 1028 M for phenol and 0.2 ppb for Pb

[24]

Powder blasting fabrication involving lithography

Nanomolar concentration levels

Amperometric detection for phenol and square-wave anodic stripping voltammetry for lead Fluorescence detection

Surface-enhanced Raman scattering (SERS) Electrochemical impedance spectroscopy

[26]

o-Aminophenol (AP), Pentachlorophenol (PCP), 4,6dinitro-o-cresol (DNOC), 2nitrophenol (NP), vanillic acid (VA), and 4-hydroxybenzoic acid (HBA) Cd21 and Pb21 in the soil pore and ground water

Chlorophenol for environmental monitoring and lead in saliva

Polycarbonate

Diuron, Atrazine, and Simazine, pH, and oxygen sensors

Glass

Dipicolinic acid (DPA) and malachite green (MG)

PDMS

E. coli bacteria

Silicon, PDMS smart phonebased sensing platform

200 ppb for DPA and 500 ppb for MG Photolithography

10 cfu mL21

[25]

[27]

E. coli bacteria

PMMA

Hg21in water

Paper based PtNPs as a signal amplification probe for enzymatic oxidation of TMB PDMS

Hg21in water

Mold fabrication, hot embossing Paper-based colorimetric device

6 cfu mL21

qPCR

[28]

0.01 µM

Colorimetric

[29]

10 pM

Surface-enhanced Raman scattering Anodic stripping voltammetry and differential pulse voltammetry Absorbance

[30]

Fluorescence measurement

[33]

Surface-enhanced Raman spectroscopy Confocal surfaceenhanced Raman spectroscopy Anodic stripping voltammetry

[34]

Cyclic voltammetry

[37]

Hg21

PDMS molding, Au Ag Au three-electrode system

Photolithography, phototyping technique

3 ppb

Hg21 and Pb21

PDMS chip, photonic lab-ona-chip PDMS

Photolithography

Malachite green

PDMS

Pattern replication from master mold

2.59 µM for Hg21, 4.19 µM for Pb21 0.6 µg L21 for Hg 21 and 16 µg L21 for dithiocarbamate pesticide ziram 1 2 ppb

Methyl Parathion

PDMS (alligator-teeth-shaped microfluidic channel)

Pattern replication from master molds

0.1 ppm

Mn21, Zn21, Cd21, and Pb21 in blood

PDMS microfluidic layer

Electrodeposition, soft lithography

Nitrate in water

Glass substrate PDMS-based microfluidics Glass substrate mobile phonesensing platform PMMA

Photolithography

20 µM for Mn21, 15 µM for Zn21, 9 µM for Cd21, 5 µM for Pb21 25 ppb

Photolithography

0.2 ppm for nitrate

Cyclic voltammetry

[38]

Two-step embossing and solvent welding technique

Not stated

CE and microchip electrophoresis

[39]

Hg21 and dithiocarbamate pesticide ziram

Nitrate in water Parabens and nonsteroidal antiinflammatory drugs

Direct laser micromilling

[31]

[32]

[35]

[36]

(Continued)

Table 8.1 (Continued) Analyte

Material

Fabrication

Limit of detection (LOD)

Technique

Reference

Pb21

Graphene Oxide -PDMS chips, PDMS microfluidic chip, Screen printed carbon electrode printed on polycarbonate sheet PDMS microfluidic chip, 11mercaptoundecanoic acidmodified AuNPs PDMS microchips

Photolithography

0.5 ppb

Electrochemical detection

[40]

Photolithography

10 µM

Colorimetric

[41]

Oxygen plasma treatment Micro electromechanical systems Micromilling Photolithography, top anodic bonding

30 ppb for Pb21 and 89 ppb for Al31 8 ppb

Colorimetric

[42]

Square-wave anodic stripping voltammetry Colorimetric HPLC-FLD analysis

[43]

Photolithography

0.018 ppb

[46]

Not defined

1 nM

Square-wave anodic stripping voltammetry Electrochemical detection

Pb21

Pb21 and Al31 in water Pb21

Cyclic olefin copolymer polycarbonate

Phosphate Polycyclic aromatic hydrocarbons from water

Polymethyl methacrylate Silicon/glass chips functionalization with PDMS and nanoporous organosilicate PDMS microfluidic chip, polycarbonate screenprinted electrode Polymethylmethacrylate (PMMA) and polycarbonate for screen printed electrode

Polybrominated diphenyl ethers in seawater Sarin

0.3 ppm Not stated

[44] [45]

[47]

Micro total analysis systems with nanomaterials

193

was not convenient for the practical use and analysis, it was a very strong proof-ofconcept demonstration for the possible future applications of µTAS in daily life. In another interesting study reported in 2018, Martinez-Cisneros and colleagues reported the analysis of nitrate and nitrite ions by using a µTAS, which is composed of integrated microfluidics, electronics, photometric detection, and pretreatment units [52]. The tested concentration range between 0.1 and 25 mg L21 for nitrite ions and 0.5 and 25 mg L21 for nitrate ions was a proof for the sensitivity of the developed µTAS. In the µTAS technology, analyte could be measured with most analytical chemistry methods such as mass spectrometry, amperometry, conductivity, and optical methods like absorbance, fluorescence, laser-induced flouorescence, infrared and Raman spectroscopy, scattering, refractive index, and surface plasmon resonance. The electrochemical detection ensures that the low detection limit is achieved and also provides low power requirements. Table 8.1 shows the recent examples of µTAS systems in environmental applications.

8.4.2 Analysis of food samples Many µTAS used in the detection of microorganisms include sample preparation (i.e., condensation, extraction, and purification) and biochemical reactions (i.e., immunological reactions, enzymatic reactions, DNA analysis, etc.). In the detection of microorganisms in food samples (except aqueous and nonviscous samples), it is not possible to apply the food sample directly to the µTAS. Sample preparation step including food homogenate preparation, pre-enrichment, and enrichment should be applied before the loading of sample to the µTAS [53]. Thus, the necessary equipment for the sample preparation step is integrated with the µTAS, which is crucial in food microbiology applications. Target microorganisms, especially pathogens, are sometimes found in very small amounts in foods. In such cases, it is necessary to use large volumes of samples to determine the presence of these microorganisms. This problem is attempted to be solved by the condensation step consisting membrane filtration and specific cell capture in µTAS [54]. In a study in which µTAS and PCR system were used together [55], multiple bead-based fluidic system was developed for fast, easy, and simultaneous detection of pathogens in food samples (egg, pork, chicken and mollusk meat, fish, ice cream, and milk powder). The target pathogens were Staphylococcus aureus, Listeria monocytogenes, Vibrio parahemolyticus, Shigella sonnei, Enterobacter sakazakii, E. coli O157: H7, Camplyobacter jejuni, and Salmonella enterica serovar Typhi. In this study, the beads immobilized with the specific oligonucleotide probe in the system were placed in microchannels. Before the analyses of food samples, homogenate was prepared, pre-enriched, and then DNA was isolated and loaded on µTAS. Fluorescence-labeled PCR products from pathogenic microorganisms were pumped into microchannels. Hybridization was performed with oligonucleotide immobilized beads and the resulting hybridization signal (fluorescence signal) was measured. The detection of target pathogens was performed in ,30 min with high sensitivity

194

Handbook of Nanomaterials in Analytical Chemistry

and specificity. The detection limit for bacterial species was determined to be between 5 3 102 and 6 3 103 cfu mL21. In the study, it has been observed that the developed PCR µTAS hybrid system can be effectively used in the detection of multiple pathogens in different food samples. In another study conducted by Sayad and coworkers [56], the loop-mediated isothermal amplification integrated disk-shaped µTAS was designed and prepared for the detection of Salmonella in tomato samples contaminated with Salmonella enteritidis. In their study, DNA was isolated from homogenization prepared from tomato samples and the obtained isolate was loaded into µTAS. The detection of target pathogen was successfully carried out by using the developed µTAS. The detection limit of the µTAS was found to be 5 3 103 ng µL21. It was reported that the entire analysis, including the sample preparation step, was completed in 70 min. Po¨hlmann et al. [57] investigated the feasibility of µTAS combined with electrochemical biosensor in the detection of foodborne bacteria. In this study, Amperometric detector was used for the detection of E. coli. The detection limit for E. coli was found to be 5.5 3 102 cfu mL21. In addition, it has been shown that the differentiation and detection of two Gram-positive (E. coli and Hafnia alvei) and two Gram-negative (Listeria innocua and Bacillus subtilis) bacteria can be performed by using messenger enzyme in this system. In a study reported by Morant-Mi´nana [58], a µTAS was designed and developed for the sensitive detection of Camplyobacter spp. For this purpose, a thin-film gold electrode-based electrochemical sensor having nucleic acid as the recognition element on a surface of cyclo-olefin polymer substrate was used for the preparation of µTAS system. The obtained results confirmed that the concentration of PCR products is linearly correlated in the range between 1 and 25 nM and the detection limit was found as 90 pM. In another study, a carcinogenic compound that is commonly used in food products, Sudan I, was successfully detected by a µTAS [59]. The developed chip was based on thin-layer chromatography and surface-enhanced Raman scattering spectroscopy in the aim of sensitive detection. The obtained low detection level (1 ppm) gives the opportunity of using a low-cost and reliable device for food-screening applications. Garcia-Aljaro and colleagues [60] developed an immunosensor having carbon nanotube (CNT) for the sensitive detection of T7 bacteriophage (virus) and E. coli O157:H7 (bacterium). The transduction materials consisted of specific antibody functionalized CNTs aligned in parallel bridging two Au electrodes to function as a chemiresistive biosensor. The limit of detection values for were obtained as 103 PFU mL21 and 103 105 cfu mL21 for T7 bacteriophage and E. coli O157:H7, respectively. In another interesting work [61], the combination of CNTs, increased chemiluminescence feature and a cooled charge-coupled device detector to enhance the sensitive detection of Staphylococcal enterotoxin B in food samples was carried out by Yang et al. For this purpose, anti-Staphylococcal enterotoxin B antibody was immobilized on the surface of CNTs and the CNT/antibody was conjugated to the polycarbonate surface. Then, ELISA technique was applied for the detection of

Micro total analysis systems with nanomaterials

195

Staphylococcal enterotoxin B in meat baby food, soy milk, and apple juice samples. The obtained detection limit was 0.01 ng mL21 that was lower than traditional ELISA assays.

8.5

Conclusions

This chapter demonstrates and highlights the recent progresses of µTAS as unique concept in the sensitive detection of target compound/s in food and environmental samples. The need of cheap, fast, and environmentally friendly approaches has become a “must” in modern world’s biotechnological applications. As µTAS meets functional abilities of laboratories in a small-sized, easy-to-use, and cost-efficient approach, the concept has a high potential in the analysis of food and environmental samples. In the past years, there has been gradually increasing attention in the design and fabrication of µTAS. The number of reported research showed that µTAS having excellent features (quick response in the target analysis, no requirement for skilled researcher, and small sample volume needed) are efficient and promising platforms for the sensitive analysis of food and environmental samples.

References [1] M.L. Kovarik, D.M. Ornoff, A.T. Melvin, N.C. Dobes, Y. Wang, A.J. Dickinson, et al., Micro total analysis systems: fundamental advances and applications in the laboratory, clinic, and field, Anal. Chem. 85 (2) (2013) 451 472. [2] S. Bu¨yu¨ktiryaki, Y. Su¨mbelli, R. Kec¸ili, C.M. Hussain, Lab-on-chip platforms for environmental analysis, in: Paul Worsfold, Colin Poole, Alan Townshend, Manuel Miro´ (Eds.), Encyclopedia of Analytical Science, Third Edition, Academic Press, Massachusetts, USA, 2019, pp. 267 273. [3] C.M. Hussain, Magnetic nanomaterials for environmental analysis, in: C.M. Hussain, B. Kharisov (Eds.), Advanced Environmental Analysis-Application of Nanomaterials, The Royal Society of Chemistry, London, UK, 2017. [4] R. Kec¸ili, C.M. Hussain, Recent progress of ımprinted nanomaterials in analytical chemistry, Int. J. Anal. Chem. (2018). Article ID8503853. [5] R. Kec¸ili, S. Bu¨yu¨ktiryaki, C.M. Hussain, Advancement in bioanalytical science through nanotechnology: past, present and future, TrAC Trend Anal. Chem. 110 (2019) 259 276. [6] J.S. Kilby, The integrated circuit’s early history, Pro. IEEE 88 (1) (2000) 109 111. [7] S.C. Terry, J.H. Hermanand, J.B. Angell, A gas chromatographic air analyzer fabricated on a silicon wafer, IEEE Trans. Electron Dev. 26 (12) (1979) 1880 1886. [8] A. Manz, N. Graber, H.M. Widmer, Miniaturized total chemical analysis systems: a novel concept for chemical sensing, Sensor Actuat. B Chem. 1 (1 6) (1990) 244 248. [9] K. Seiler, D.J. Harrison, A. Manz, Planar glass chips for capillary electrophoresis : repetitive sample injection, quantitation, and separation efficiency, Anal. Chem. 15 (1993) 1481 1488.

196

Handbook of Nanomaterials in Analytical Chemistry

[10] A.T. Woolley, R.A. Mathies, Ultra-high-speed DNA fragment separations using microfabricated capillary array electrophoresis chips, Proc. Natl. Acad. Sci. USA 91 (1994) 11348 11352. [11] K. Adamski, W. Kubicki, R. Walczak, 3D printed electrophoretic lab-on-chip for dna separation, Procedia Eng. 168 (2016) 1454 1457. [12] D. Figeys, Y. Ning, R. Aebersold, A microfabricated device for rapid protein identification by microelectrospray ion trap mass spectrometry, Anal. Chem. 69 (16) (1997) 3153 3160. [13] B.H. Weigl, P. Yager, Silicon-microfabricated diffusion-based optical chemical sensor, Sensor Actuat. B Chem. 38 39 (1997) 452 457. [14] P. Xie, X. Cao, Z. Lin, M. Javanmard, Top-down fabrication meets bottom-up synthesis for nanoelectronic barcoding of microparticles, Lab Chip 17 (11) (2017) 1939 1947. [15] D.J. Harrison, K. Fluri, N. Chiem, T. Tang, Z. Fan, Micromachinng chemical and biochemical analysis and reaction systems on glass substrates, Sensor Actuat. B Chem 33 (1 3) (1996) 105 109. [16] J.H. Daniel, S. Iqbal, R.B. Millingston, D.F. Moore, C.R. Lowe, D.L. Leslie, et al., Sensor Actuat. A Phys. 81 (1998) 81 88. [17] X. Pang, A.C. Lewis, M. Ro´denas-Garcı´a, Microfluidic lab-on-a-chip derivatization for gaseous carbonyl analysis, J. Chromatogr. A 1296 (2013) 93 103. [18] D. Hu¨r, M.G. Say, S. Diltemiz, F. Duman, A. Erso¨z, R. Say, 3D micropatterned allflexible microfluidic platform for microwave-assisted flow organic synthesis, ChemPlusChem 83 (1) (2018) 42 46. [19] M. Medina-Sa´nchez, A. Merkoc¸i, Micro- and nanomaterials based detection systems applied in lab-on-a-chip technology, Handbook of Green Analytical Chemistry, John Wiley & Sons, Ltd, Chichester, UK, 2012, pp. 85 102. [20] M. Pumera, A. Merkoc¸i, S. Alegret, New materials for electrochemical sensing VII. Microfluidic chip platforms, TrAC Trend Anal. Chem. 25 (3) (2006) 219 235. [21] M. Medina-Sa´nchez, C.C. Mayorga-Martinez, T. Watanabe, T.A. Ivandini, Y. Honda, F. Pino, et al., Microfluidic platform for environmental contaminants sensing and degradation based on boron-doped diamond electrodes, Biosens. Bioelectron. 75 (2016) 365 374. [22] Y. Ding, M.F. Mora, G.N. Merrill, C.D. Garcia, The effects of alkyl sulfates on the analysis of phenolic compounds by microchip capillary electrophoresis with pulsed amperometric detection, Analyst 132 (10) (2007) 997 1004. [23] Z. Zou, A. Jang, E. MacKnight, P.-M. Wu, J. Do, P.L. Bishop, et al., Environmentally friendly disposable sensors with microfabricated on-chip planar bismuth electrode for in situ heavy metal ions measurement, Sensor Actuat. B Chem. 134 (1) (2008) 18 24. [24] Y. Lin, C.A. Timchalk, D.W. Matson, H. Wu, K.D. Thrall, Integrated microfluidics/ electrochemical sensor system for monitoring of environmental exposures to lead and chlorophenols, Biomed. Microdev. 3 (4) (2001) 331 338. [25] I.B. Tahirbegi, J. Ehgartner, P. Sulzer, S. Zieger, A. Kasjanow, M. Paradiso, et al., Fast pesticide detection inside microfluidic device with integrated optical pH, oxygen sensors and algal fluorescence, Biosens. Bioelectron. 88 (2017) 188 195. [26] L.X. Quang, C. Lim, G.-H. Seong, J. Choo, K.-J. Do, S.-K. Yoo, A portable surfaceenhanced Raman scattering sensor integrated with a lab-on-a-chip for field analysis, Lab Chip 8 (12) (2008) 2214 2219. [27] J. Jiang, X. Wang, R. Chao, Y. Ren, C. Hu, Z. Xu, et al., Smartphone based portable bacteria pre-concentrating microfluidic sensor and impedance sensing system, Sensor Actuat. B Chem. 193 (2014) 653 659.

Micro total analysis systems with nanomaterials

197

[28] U. Dharmasiri, M.A. Witek, A.A. Adams, J.K. Osiri, M.L. Hupert, T.S. Bianchi, et al., Enrichment and detection of Escherichia coli O157: H7 from water samples using an antibody modified microfluidic chip, Anal. Chem. 82 (7) (2010) 2844 2849. [29] W. Chen, X. Fang, H. Cao, J. Kong, A simple paper-based colorimetric device for rapid mercury(ii) assay, Sci Rep. 6 (1) (2016) 31948. [30] E. Chung, R. Gao, J. Ko, N. Choi, D.-W. Lim, E.-K. Lee, et al., Trace analysis of mercury(II) ions using aptamer-modified Au/Ag core-shell nanoparticles and SERS spectroscopy in a microdroplet channel, Lab Chip 13 (2) (2013) 260 266. [31] C. Chen, J. Zhang, Y. Du, X. Yang, E. Wang, Microfabricated on-chip integrated AuAg-Au three-electrode system for in situ mercury ion determination, Analyst 135 (5) (2010) 1010 1014. [32] B. Ibarlucea, C. Dı´ez-Gil, I. Ratera, J. Veciana, A. Caballero, F. Zapata, et al., PDMS based photonic lab-on-a-chip for the selective optical detection of heavy metal ions, Analyst 138 (3) (2013) 839 844. [33] J.P. Lafleur, S. Senkbeil, T.G. Jensen, J.P. Kutter, Gold nanoparticle-based optical microfluidic sensors for analysis of environmental pollutants, Lab Chip 12 (22) (2012) 4651 4656. [34] S. Lee, J. Choi, L. Chen, B. Park, J.B. Kyong, G.H. Seong, et al., Fast and sensitive trace analysis of malachite green using a surface-enhanced Raman microfluidic sensor, Anal. Chim. Acta 590 (2) (2007) 139 144. [35] D. Lee, S. Lee, G.H. Seong, J. Choo, E.K. Lee, D.G. Gweon, et al., Quantitative analysis of methyl parathion pesticides in a polydimethylsiloxane microfluidic channel using confocal surface-enhanced raman spectroscopy, Appl. Spectrosc. 60 (4) (2006) 373 377. [36] P. Jothimuthu, R.A. Wilson, J. Herren, E.N. Haynes, W.R. Heineman, I. Papautsky, Lab-on-a-chip sensor for detection of highly electronegative heavy metals by anodic stripping voltammetry, Biomed Microdev. 13 (2011) 695 703. [37] M.R. Gartia, B. Braunschweig, T.W. Chang, P. Moinzadeh, B.S. Minsker, G. Agha, et al., The microelectronic wireless nitrate sensor network for environmental water monitoring, J. Environ. Monit. 14 (12) (2012) 3068 3075. [38] X. Wang, M.R. Gartia, J. Jiang, T.-W. Chang, J. Quian, Y. Liu, et al., Audio jack based miniaturized mobile phone electrochemical sensing platform, Sens. Actuators B Chem. 209 (2015) 677 685. [39] Y.H. Tennico, V.T. Remcho, In-line extraction employing functionalized magnetic particles for capillary and microchip electrophoresis, Electrophoresis 31 (15) (2010) 2548 2557. [40] A. Chałupniak, A. Merkoc¸i, Graphene oxide-poly(dimethylsiloxane)-based lab-on-achip platform for heavy-metals preconcentration and electrochemical detection, ACS Appl. Mater Interfaces 9 (51) (2017) 44766 44775. [41] C. Fan, S. He, G. Liu, L. Wang, S. Song, A portable and power-free microfluidic device for rapid and sensitive lead (Pb21) detection, Sensors 12 (7) (2012) 9467 9475. [42] C. Zhao, G. Zhong, D.-E. Kim, J. Liu, X. Liu, A portable lab-on-a-chip system for gold-nanoparticle-based colorimetric detection of metal ions in water, Biomicrofluidics 8 (5) (2014) 052107. [43] A. Jang, Z. Zou, E. MacKnight, P.M. Wu, I.S. Kim, C.H. Ahn, et al., Development of a portable analyzer with polymer lab-on-a-chip (LOC) for continuous sampling and monitoring of Pb(II), Wat. Sci. Tech. 60 (11) (2009) 2889 2896. [44] C.M. McGraw, S.E. Stitzel, J. Cleary, C. Slater, D. Diamond, Autonomous microfluidic system for phosphate detection, Talanta 71 (3) (2007) 1180 1185.

198

Handbook of Nanomaterials in Analytical Chemistry

[45] L. Foan, J. El Sabahy, F. Ricoul, B. Bourlon, S. Vignoud, Development of a new phase for lab-on-a-chip extraction of polycyclic aromatic hydrocarbons from water, Sens. Actuators B Chem. 255 (2018) 1039 1047. [46] A. Chałupniak, A. Merkoc¸i, Toward integrated detection and graphene-based removal of contaminants in a lab-on-a-chip platform, Nano Res. 10 (7) (2017) 2296 2310. [47] H.Y. Tan, Lab-on-a-chip for rapid electrochemical detection of nerve agent Sarin, Biomed Microdev. 16 (2) (2014) 269 275. [48] Z. Zou, A. Jang, E.T. MacKnight, P.-M. Wu, J. Do, J.S. Dhim, et al., An on-site heavy metal analyzer with polymer lab-on-a-chips for continuous sampling and monitoring, IEEE Sens. J. 9 (5) (2009) 586 594. [49] M. Czugala, R. Gorkin, T. Phelan, J. Gaughran, V. Fabio Curto, J. Ducre´e, et al., Optical sensing system based on wireless paired emitter detector diode device and ionogels for lab-on-a-disc water quality analysis, Lab Chip 12 (23) (2012) 5069 5078. [50] N. Wang, X. Zhang, B. Chen, W. Song, N.Y. Chan, H.L.W. Chan, Microfluidic photoelectrocatalytic reactors for water purification with an integrated visible-light source, Lab Chip 12 (20) (2012) 3983 3990. [51] S.A. Lee, C. Yang, A smartphone-based chip-scale microscope using ambient illumination, Lab Chip 14 (16) (2014) 3056 3063. [52] C. Martinez-Cisneros, Z. da Rocha, A. Seabra, F. Valdes, J. Alonso-Chamarro, Highly integrated autonomous lab-on-a-chip device for on-line and in situ determination of environmental chemical parameters, Lab Chip 18 (2018) 1884 1890. [53] C. Sakamoto, N. Yamaguchi, M. Yamada, H. Nagase, M. Seki, M. Nasu, Rapid quantification of bacterial cells in potable water using a simplified microfluidic device, J. Microbiol. Meth. 68 (2007) 643 647. [54] W. Liu, L. Zhu, Environmental microbiology-on-a-chip and its feature impacts, Trends Biotechnol. 23 (4) (2005) 174 179. [55] S. Jin, B. Yin, B. Ye, Multiplexed bead- based mesofluidic system for detection of food-borne pathogenic bacteria, Appl. Environ. Microbiol. 75 (21) (2009) 6647 6654. [56] A.A. Sayad, F. Ibrahim, S.M. Uddin, K.X. Pei, M.S. Mohktar, M. Madou, et al., A microfluidic lab-on-a-disc integrated loop mediated isothermal amplification of foodborne pathogen detection, Sens. Actuator. B Chem. 227 (2016) 600 609. [57] C. Po¨hlmann, Y. Wang, M. Humenik, B. Heidenreich, M. Gareis, M. Sprinzl, Rapid, specific and sensitive electrochemical detection of foodborne bacteria, Biosens. Bioelectron. 24 (2009) 2766 2771. [58] M.C. Morant-Mi´nana, J. Elizalde, Microscale electrodes integrated on COP for real sample Camplyobacter spp. detection, Biosens. Bioelectron. 70 (2015) 491 497. [59] X. Kong, K. Squire, X. Chong, A.X. Wang, Ultra-sensitive lab-on-a-chip detection of Sudan I in food using plasmonics-enhanced diatomaceous thin film, Food Control 79 (2017) 258 265. [60] C. Garcia-Aljaro, L.N. Cella, D.J. Shirale, M. Park, F. Javier Munoz, M.V. Yates, et al., Carbon nanotubes-based chemiresistive biosensors for detection of microorganisms, Biosens. Bioelectron. 26 (2010) 1437 1441. [61] M. Yang, Y. Kostov, H.A. Bruck, A. Rasooly, Carbon nanotubes with enhanced chemiluminescence immunoassay for CCD-based detection of Staphylococcal enterotoxin B in food, Anal. Chem. 80 (2008) 8532 8537.

Electrochemically engineered nanoporous photonic crystal structures for optical sensing and biosensing

9

Cheryl Suwen Law1,2,3, Lluı´s F. Marsal4 and Abel Santos1,2,3 1 School of Chemical Engineering and Advanced Materials, The University of Adelaide, Adelaide, SA, Australia, 2Institute for Photonics and Advanced Sensing (IPAS), The University of Adelaide, Adelaide, SA, Australia, 3ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP), The University of Adelaide, Adelaide, SA, Australia, 4Department of Electronic, Electric, and Automatics Engineering, Universitat Rovira i Virgili, Tarragona, Tarragona, Spain

9.1

Introduction

Optical sensors are a class of devices that use various forms of light matter (i.e., photon atom) interactions to detect, interrogate, and quantify molecules for multiple applications. An optical sensor is composed of a light source that generates electromagnetic waves, a sensing platform in which light matter interactions occur, and a detector that identifies and quantifies spectral shifts in electromagnetic waves upon interaction with targeted analytes [1 3]. The sensing principle of an optical sensor is based on shifts in the characteristic optical signal of an optical platform resulting from interactions with analyte molecules, which are then translated into quantitative and/or qualitative measurements. As the sensing platform characterizes the light matter interaction, its design and engineering is crucial. Recent advances in nanotechnology now make possible the development of optical sensing platforms with outstanding optical properties [4,5]. These nanoplatforms can be coupled with various spectroscopic techniques such as surface plasmon resonance spectroscopy (SPR) [4 7], localized SPR (LSPR) [8,9], surface-enhanced Raman spectroscopy [10 12], photoluminescence (PL) spectroscopy [13,14], and reflectometric interference spectroscopy (RIfS) to develop state-of-the-art sensing systems [15,16]. Photonic crystals (PCs) are a type of optical materials that mold the flow of electromagnetic waves by multiple Bragg scattered interferences defined by Bloch modes, which can be controlled by structural engineering of PCs in a multidimensional manner (i.e., 1D, 2D, or 3D) [17 19] (Fig. 9.1A). Nanoporous PCs have

Handbook of Nanomaterials in Analytical Chemistry. DOI: https://doi.org/10.1016/B978-0-12-816699-4.00009-8 Copyright © 2020 Elsevier Inc. All rights reserved.

202

Handbook of Nanomaterials in Analytical Chemistry

Figure 9.1 Structural engineering of nanoporous photonic crystals. (A) Schematics showing the basic structure of 1D, 2D, and 3D photonic crystals with distributions of high and low refractive index. (B) Schematic comparison between high and low refractive index distribution in 1D nonnanoporous and nanoporous photonic crystals.

emerged as promising ultra-sensitive optical sensing platforms due to their lightmodulating capabilities within the broadband spectral regions (i.e., from UV to IR), nanoporous structure that facilitates mass transport of molecular species involved in binding events, and high specific surface area that provides large number of functional binding sites available on the platform [20]. In addition, the production of nanoporous PCs by self-organization approaches is not only fully scalable and cost competitive, but also allows a precise control over the structures of PCs at the nanoscale and it is compatible with conventional micro- and nanofabrication approaches for integration into fully functional devices (Fig. 9.1B). A distinct example of nanoporous PC platform material is porous silicon (pSi), which is produced by electrochemical etching of silicon in hydrofluoric acid-based electrolytes [21 23]. Despite the excellent optoelectronic properties of pSi as a sensing platform, it requires additional passivation steps to improve the chemical stability due to its low mechanical strength and hazardous fabrication process [24,25]. As an alternative platform material, nanoporous anodic alumina photonic crystals (NAA-PCs) produced by nonabrasive electrochemical oxidation has been utilized in the development of optical sensing systems in combination with a broad

Electrochemically engineered nanoporous photonic crystal structures

203

range of photonic technologies due to their chemical, physical, and optical stability [26]. This well-established nanofabrication method is able to engineer the nanoporous structure of NAA-PCs by means of anodization, producing a set of unique libraries of PC structures with finely tuned structural and optical properties across the spectral region. Furthermore, the chemical selectivity of NAA-PCs toward targeted analytes can be achieved by surface chemistry modifications with a wide variety of functional molecules [27]. Various anodization approaches have been explored to achieve precise structural engineering of NAA-PCs for controllable optical properties, paving the way for advanced NAA-PC-based sensing systems with high performance and broad applicability. This chapter provides a comprehensive review on the fundamentals of NAA-PC technology, encompassing the fabrication process and properties of this singular PC platform material that make it suitable for optical chemo- and biosensing systems. The most significant advances in the development of NAA-PC-based optical sensing systems with representative examples of applicability are compiled, concluding with a general overview and a prospective outlook on the future trends in this field.

9.2

Fabrication and properties: nanoporous anodic alumina as effective medium

9.2.1 Fabrication of nanoporous anodic alumina Nanoporous anodic alumina (NAA) is a thin film composed of a matrix of alumina (aluminum oxide—Al2O3) featuring arrays of straight cylindrical nanopores with closed hemispherical bottom tips that grow at the center of the hexagonal cells aligned perpendicularly to the underlying aluminum substrate [26] (Fig. 9.2A). NAA is fabricated by anodization of aluminum, an electrochemical process where both electrodes (i.e., aluminum as anode and platinum as cathode) are partially immersed in aqueous acid electrolytes under applied voltage or current density [28,29]. The application of an external electric field drives the flow of ionic species (i.e., Al31, O22, OH2, H1) involved in the competing formation and dissolution of oxide at the interfaces of the oxide barrier layer, promoting the growth of NAA [26,30] (Fig. 9.2B). With the versatility in the nanoporous structure of NAA that allows precise modulation of light propagation, it can be readily utilized as an effective medium platform to develop unique PC structures [27]. NAA is a binary composite matrix formed by air (i.e., 1 RIU) and alumina (i.e., B1.70 RIU), where the spatial distribution of these two components at the micro/nanoscale establishes the macroscopic optical properties of this nanomaterial (Fig. 9.2C). The optical properties of NAA-PCs such as effective refractive index and effective dielectric constant can be estimated by averaging the properties of individual constituents (i.e., air and alumina), depending on the spatial distribution (i.e., PC structure, e.g., distributed

204

Handbook of Nanomaterials in Analytical Chemistry

Figure 9.2 Fabrication and optical properties of nanoporous anodic alumina photonic crystals. (A) Schematic illustration of an electrochemical reactor used to fabricate NAA-PCs by anodization (left) and details of the oxide barrier layer located at the bottom tip of the nanopores where the electrochemical reactions occur. (B) Structure and geometric features of NAA produced by two-step anodization with tilted 3D view of NAA structure (left) (Lp—nanopore length) and top view of NAA structure (right) (dint—interpore distance and dp—nanopore diameter). (C) Structural engineering of effective medium of NAA-PCs with details of the intrinsic relationship between nanoporous geometry and effective medium approximation.

Bragg reflector, and gradient-index filter) and the intrinsic properties of constituting components (i.e., refractive indices/dielectric constant). Depending on the spatial distribution and the intrinsic properties of constituting components, various

Electrochemically engineered nanoporous photonic crystal structures

205

effective medium approximation models, for instances, Maxwell-Garnett, Bruggeman, Lorentz-Lorenz, Monecke, Drude, Looyenga-Landau-Lifshitz, can be used to describe the effective medium of NAA-PCs [31]. The nanopores of NAA can be further modified by filling or coating its inner nanoporous structure with other materials, using different deposition techniques (e.g., electrodeposition, atomic layer deposition, and infiltration) to produce composite PCs with distinctive and finely tuned optical properties across the spectral regions [32 34]. Pioneering studies on NAA-PCs focused on the light matter interactions in NAA-PC platforms featuring hexagonally arranged straight cylindrical nanopores produced by a combination of nanoimprint lithography and one-step anodization or self-organized NAA-PCs produced by two-step anodization [35 38]. The modulation of light within these structures is achieved when the photons flow transversally across the nanoporous structure of NAA-PCs. The seminal studies by Masuda and coworkers and Go¨sele and coworkers reported the presence of a characteristic photonic stopband (PSB) in the optical spectrum of organized NAA-PCs, the position of which can be tuned by modifying lattice constant (i.e., interpore distance—distance between the centers of adjacent nanopores) and porosity (i.e., pore diameter) of the NAA-PC platform. Significant research effort has been dedicated to the fabrication of NAA-PCs featuring longer interpore distances using different acid electrolytes (i.e., oxalic, sulfuric, phosphoric, malonic, selenic, phosphonic, tartaric, citiric, phosphonoacetic, etidronic) [39 53]. Nonetheless, the versatility of NAA-PCs to control light across the spectral regions is limited by the range of available interpore distances. It is worth noting that the photonic band structure of NAA that arises from its nanopore periodicity has yet to be utilized in optical sensing applications. This inherent limitation can be addressed by the introduction of in-depth and multidimensional engineering of the effective medium of NAA by pulse-like anodization approaches to attain effective light control in the different regions of the spectrum.

9.2.2 Structural engineering of nanoporous anodic alumina Based on the linear correlation between anodization voltage and nanopore diameter, as established by O’Sullivan and Wood, nanopores of NAA can be modulated following a pulse-like dynamic modifications of anodization voltage during the growth of NAA [54,55]. However, the translation of this variation in anodizing voltage/current density into nanopore diameter modulations is limited by the presence of an oxide barrier layer located at the nanopores bottom tips that acts as an electrical and ionic insulator. When the external electric field experiences a sudden change during anodization, the flow of ionic species across the barrier layer is altered, undergoing a recovery process that it is influenced by the electric field modification and the thickness of oxide barrier layer [56 58]. To overcome the limitations imposed by the oxide barrier layer, seminal works by Lee and coworkers demonstrated the utilization of anodization strategies based on various combinations of voltage or current density pulses switched between different anodization regimes (i.e., hard and mild anodization) to engineer the inner

206

Handbook of Nanomaterials in Analytical Chemistry

porosity of NAA with precision [59 62]. These pulse-like anodization approaches are able to modulate the inner nanoporous structure of NAA with precision and versatility according to the difference in the porosity obtained from mild and hard regimes. With an optimal design of anodization conditions, for example, level of anodizing voltage or current, temperature, acid electrolyte, variations in electric field can be effectively translated into nanopore modulations. Although this approach can overcome the limitations imposed by the oxide barrier layer and prevent nanopore branching, challenges exist due to the limited controllability during hard anodization regime in terms of NAA growth rate, porosity level, and Joule’s heat generation [56 58]. Alternatively, pulse-like anodization under mild conditions provides a more controllable means to engineer the effective medium of NAA with precision. Despite the slow oxide growth rate in mild regime (i.e., 3 8 μm h21), these approaches enable the fine tuning the optical properties of NAA-PCs across the spectral regions with a better controllability. In recent years, numerous studies have realized and developed different NAAPC architectures based on rationally designed pulse-like anodization strategies. Some representative examples of NAA-PCs are optical microcavities (NAA-μCVs), distributed Bragg reflectors (NAA-DBRs), gradient-index filters (NAA-GIFs), apodized DBRs and GIFs (Apo-NAA-DBRs and Apo-NAA-GIFs), bandpass filters (NAA-BPFs) and linear variable bandpass filters (NAA-LVBPFs). Some excellent review articles have recently described the fundamental concepts and realization of NAA-PCs [27,32]. To generate NAA-PCs with modulated nanopores, rationally designed complex profiles are implemented into pulse-like anodization. For instances, a stepwise pulse anodization (STPA) profile is utilized in the fabrication of NAA-DBRs in order to in-depth modulate the nanopores following a stepwise manner. As a result of their stepwise-modulated effective medium, NAA-DBRs have a characteristically broad PSB in their transmission spectra, the position and features of which can be readily tuned by different anodization parameters [63,64]. On the other hand, NAA-GIFs are fabricated by sinusoidal pulse anodization (SPA) in which the anodization voltage or current density is pulsed between high and low values in a sinusoidal manner [65]. The resulting NAA-PCs are featured with a smooth sinusoidally modulated porosity, giving rise to a characteristically narrow and well-resolved PSB in its transmission spectra. These anodization profiles (i.e., STPA and SPA) can be modified with truncating functions such as Kaiser windows, Gaussian and apodization. [66] Apo-NAA-DBRs and Apo-NAA-GIFs are produced by apodizing STPA and SPA anodization profiles, respectively [67 70]. The characteristic PSB of these NAA-PCs is similar to that of their nonapodized counterparts but with a narrower width due to the apodization of their effective medium. Several studies have demonstrated the application of different apodization functions to STPA and SPA to engineer the photonic features of NAA-DBRs and NAA-GIFs. NAA-μCVs, a type of PC structure that is capable of confining light to small volumes by resonant recirculation of electromagnetic waves, usually have a physical cavity layer featuring straight cylindrical nanopores sandwiched between two highly reflective mirrors (e.g., NAA-DBRs, NAA-GIFs) [71 73]. NAA-μCVs with different nanoporous architecture have been realized [74]. Similar to other

Electrochemically engineered nanoporous photonic crystal structures

207

NAA-PCs, NAA-μCVs possess a characteristic PSB at those wavelengths where constructive light interference occurs in the PC structure, denoting a maximum of light reflection by the mirrors. The introduction of a cavity section between the mirrors causes destructive interferences, creating a resonance band within the characteristic PSB. The characteristics of the cavity layer and the mirrors determine the conditions where light confinement is at a maximum. NAA-BPFs are a class of PC structures with light-filtering ability by allowing the transmission of photons with certain energy level while inhibiting the pass of light of all other wavelengths [68,75]. Based on their range of allowed wavelengths, they are categorized into (1) longpass filters, which allow the pass of light of long wavelength; (2) shortpass filters, which allow the pass of light with short wavelength; and (3) bandpass filters, which allow the transmission of a band of wavelengths while forbidding light of other wavelengths. Other types of NAA-BPFs with complex transmission bands (i.e., several transmission bands located at different sections of UV-visibleNIR spectrum) can be produced by rationally designed anodization strategies. NAA-LVBPFs can be produced by combining anodization and chemical etching to engineer their effective medium perpendicularly to the growth direction of nanopores [76]. They have a PSB with variable central wavelength, the position of which is shifted across the surface of the filter linearly. A summary of the characteristics and optical properties of the aforementioned NAA-PCs is provided in Table 9.1.

9.3

Nanoporous anodic alumina photonic crystals as optical sensing platforms

NAA-PCs have great potential as advanced optical sensing platforms as their unique and versatile physical, chemical, and optical properties can be engineered to enhance their sensing capabilities in terms of selectivity, sensitivity, and specificity. The surface chemistry of NAA-PCs can be modified with different desirable functionalities in order to achieve chemical selectivity toward target molecules and analytes for specific sensing applications. As NAA-PCs have a high specific-areato-volume ratio, the large area provides a large number of binding functional sites for targeted molecules. There are well-established protocols that can be used to modify the surface chemistry inside the nanopores in a controlled manner, depending on the type of functionalizing molecules. Organic molecules and biomolecules can be readily deposited onto the inner surface of NAA-PCs by wet chemical techniques [15,87 90] or layer-by-layer deposition (LbL) [91 93]; inorganics (i.e., metals, metal oxides, semiconductors) can be deposited on the inner surface of nanopores by LbL [94], atomic layer deposition [95,96], electrochemical deposition [97 99], or physical vapor deposition [100,101], while the modification of NAA with polymers can be done by plasma polymer deposition [102,103] or polymer grafting [104,105]. There are also other surface modification methodologies available such as chemical vapor deposition (CVD) [106,107], sol gel chemistry

208

Handbook of Nanomaterials in Analytical Chemistry

Table 9.1 Characteristics and optical properties of representative NAA-PCs. NAA-PC

Anodizationa

NAA-DBR

G

G

NAA-GIF

G

G

Apo-NAA-DBR Apo-NAA-GIF NAA-μCV

G

G

G

G

G

G

3D NAA-PC (DBR) NAA-BPFs

G

G

G

G

NAA-LBPFs

G

STPA PSTPA SPA PSTPA ASTPA ASPA STPA with constant step between mirrors SPA with constant step between mirrors SATPA with constant step between mirrors PSTPA with constant step, progressive variation of electrolyte temperature, or phase shift between mirrors SPA with final etching STPA PSTPA STPA 1 SPA SPA with asymmetric etching

Photonic features

Refs.b

G

Broad PSB

[63,70,77 82]

G

Narrow PSB

[65,69,83 85]

Narrow PSB Ultra-narrow PSB Resonance band within PSB

[69,74,86] [67 70] [71 74]

Broad PSB (inplane and out-ofplane) Versatile PSB or PSB across the spectral regions Narrow PSB with position variable across the surface

[63,64]

G

G

G

G

G

G

[68,75]

[76]

a

STPA, Stepwise pulse anodization; SPA, sinusoidal pulse anodization; SATPA, sawtooth pulse anodization; PSTPA, pseudo-stepwise pulse anodization; ASTPA, apodized stepwise pulse anodization; ASPA, apodized sinusoidal pulse anodization. b Representative references.

deposition [107,108], electroless deposition [109,110], which can be used not only to impart surface functionalities, but also to alter the surface properties of NAA-PCs (i.e., hydrophobicity, surface charge, wettability) for further functionalization. This flexibility broadens the use of NAA-PCs as sensing platforms for various chemical and biosensing applications. Some excellent review articles covering surface chemistry modifications of NAA are given in References [33,34]. NAA-PCs are optically active platforms that can be engineered to confine, guide, reflect, emit, and transmit incident light, generating stable optical signals (i.e., reflectivity, transmittance, absorbance, PL, waveguiding, and color change) for different sensing applications based on spectral shifts upon exposure to analyte molecules. Thus, NAA with various PC structures (e.g., NAA-DBRs, NAA-GIFs,

Electrochemically engineered nanoporous photonic crystal structures

209

and NAA-μCVs) can be integrated with a broad range of optical techniques such as RIfS, reflection and transmission spectroscopy, and PL spectroscopy [32,111]. This section compiles the most representative examples of chemical and biosensing systems using NAA-PCs as sensing platforms.

9.3.1 Nanoporous anodic alumina distributed Bragg reflectors NAA-DBRs are composed of stacks of NAA layers of alternating porosity that follows the stepwise pulsing of anodization voltage or current density between high and low values during STPA (Fig. 9.3). NAA-DBRs featuring a stepwise modulated porosity have a broad PSB, which shifts its position when the effective medium of NAA-DBRs is modified upon interaction with analytes of interest. The shift in the position of PSB can be used as a sensing parameter to develop optical chemical and biosensing systems. Chen et al. fabricated NAA-DBRs by galvanostatic pulse anodization using sulfuric acid under mild conditions [77]. The structural and optical properties of these NAA-DBRs were tuned across the spectral region by means of anodization parameters such as anodization period (Tp) and number of pulses (Np). The sensing performance of these NAA-DBRs was systemically assessed in terms of sensitivity (S), low limit of detection (LLoD), and linearity (R2) using RIfS. The effective medium of these NAA-DBRs was modified by infiltrating their nanopores with different solutions (i.e., D-glucose, ethanol, and isopropanol). The contrast in the refractive index of the medium filling the nanopores was translated into quantifiable changes in the effective optical thickness (ΔOTeff) of NAA-DBRs by RIfS. NAA-DBRs produced with Tp 5 1035 s and Np 5 150 pulses were most sensitive to effective medium modifications as indicated by S 5 37,931 nm RIU21, LLoD 5 0.352 RIU, and R2 5 0.9876. These optimal NAA-DBRs were integrated into a RIfS sensing system as sensing platforms for the detection of gold(III) ions (Au31). To endow NAA-DBRs with chemical selectivity toward Au31, the inner surface of nanopores was modified with 3-(mercaptopropyl)-trimethoxysilane (MPTMS) by CVD. As described by the linear relationship between ΔOTeff and concentration of Au31 ([Au31]), the sensing performance of the proposed sensing system was S 5 22.2 nm μM21, LLoD 5 0.16 μM, and R2 5 0.9983. Using galvanostatic pulse-like anodization, Chen et al. also produced a library of NAA-DBRs with different geometric and optical properties by manipulating Tp, anodization

Figure 9.3 Characteristic nanoporous geometry, anodization profile, and optical properties of NAA-DBRs.

210

Handbook of Nanomaterials in Analytical Chemistry

Figure 9.4 Examples of NAA-DBRs integrated optical sensing systems. (A-i) Illustration of the effective medium distribution of high and low refractive indices in NAA-DBRs, (A-ii) (Continued)

Electrochemically engineered nanoporous photonic crystal structures

211

L

temperature (Tan), and time ratio of high and low current density values (Rt) in the STPA profile [78]. The effective medium of these NAA-DBRs was assessed by infiltrating their nanoporous network with a mixture of ethanol and isopropanol in various ratios. The highest sensitivity (S 5 27553 nm RIU21) was achieved by NAA-DBRs fabricated with Tp 5 675 s, Tan 5 3 C, and Rt 5 6:1, as determined by RIfS. These optimized NAA-DBRs were then combined with RIfS to develop an optical sensing system to detect vitamin C molecules. They were functionalized with (3-aminopropyl)-trimethoxysilane (APTES) to achieve chemical specificity toward vitamin C molecules. ΔOTeff of these NAA-DBRs upon exposure to different concentrations of vitamin C solutions was measured in real-time using RIfS. The sensing performance of this system was determined to be S 5 227 nm μM21, LLoD 5 20 nM, and R2 5 0.9985. Another interesting feature of these NAA-DBRs was their interferometric colors, which were demonstrated to be tunable by means of fabrication parameters (i.e., anodization temperature, anodization period, ratio between time at high and low current density). In order to utilize the color change of NAA-DBRs for colorimetric sensing, these PC films were broken down into nanoporous microparticles and infiltrated with media of different refractive index such as air and isopropanol. Owing to the modifications of the effective medium of NAA-DBRs, these PC platforms underwent sharp color changes, which were quantified in terms of RGB values. The proposed visual sensing system based on NAA-DBR-microsized particles opens new opportunities for producing innovative analytical tools such as self-reporting nanocarriers and microsensors. Law et al. produced Apo-NAA-DBRs by applying apodization functions to STPA profiles under galvanostatic conditions [86] (Fig. 9.4A). The structural and optical properties of these NAA-DBRs were tuned through a systematic modification of Tp and pore-widening time (tpw). In order to assess the sensitivity of the

Representative RIfS spectra of apodized NAA-DBR under different nanopore-infiltrating mediums (i.e., air, ethanol, and water), and (A-iii) Bar chart describing the sensitivity of apodized NAA-DBRs produced as a function of anodization periods and pore-widening time. (B-i) Cross-section SEM images showing the photonic structure of NAA-DBRs with schematic illustration of representative geometric features (left) and the effective medium distribution (right). (B-ii) Optical assessment of NAA-DBRs under nonspecific adsorption conditions by measuring spectral shift in terms of refractive index of glucose solution and pore-widening time (left) as well as sensitivity as a function of fabrication parameters, and (B-iii) Calibration curves compare the sensing performance of NAA with straight pores (NAA-ST) and NAA-DBRs with modified surface chemistry (see right scheme) for the detection of mercury ions. Source: (A) Reproduced from C.S. Law, S.Y. Lim, A. Santos, On the precise tuning of optical filtering features in nanoporous anodic alumina distributed Bragg reflectors, Sci. Rep. 8 (2018) 4642, with copyright permission from Scientific Reports, 2018. (B) Reproduced from T. Kumeria, A. Santos, M.M. Rahman, J. Ferre´-Borrull, L.F. Marsal, D. Losic, Advanced structural engineering of nanoporous photonic structures: tailoring nanopore architecture to enhance sensing properties, ACS Photonics 1 (2014) 1298 1306, with copyright permission from American Chemical Society, 2014.

212

Handbook of Nanomaterials in Analytical Chemistry

effective medium of these NAA-DBRs, their nanoporous matrix was infiltrated with mediums of different refractive index (i.e., air, ethanol, and water). Shifts in the position of the characteristic PSB of these NAA-DBRs upon infiltration of nanopores were monitored in real-time using RIfS. Apodized NAA-DBRs were demonstrated to be B16% more sensitive (S 5 392 nm RIU21) than their nonapodized counterpart (S 5 339 nm RIU21), as established by the linear correlation between shifts in the position of PSB and refractive index of infiltrating medium. A longer Tp (1700 s) and a moderate tpw (4 min) were also shown to have an enhancing effect on the sensitivity of Apo-NAA-DBRs as optical sensing platforms. Kumeria et al. fabricated NAA-DBRs by pseudosinusoidal anodization profiles, modulating the effective refractive index in-depth following the level of anodization voltage [79] (Fig. 9.4B). These NAA-DBRs were used as sensing platforms in combination with RIfS to develop an optical sensing system under both nonspecific and specific adsorption conditions. The optical assessment of NAA-DBRs under nonspecific adsorption was performed by modifying the effective medium of these nanoporous structures through infiltration with glucose solutions. As the infiltrating glucose solutions were of different concentrations, there was a change in the effective refractive index of NAA-DBRs, thus red-shifting the position of characteristic PSB in the RIfS spectra. To demonstrate the sensing performance of these NAA-DBRs under specific adsorption conditions, NAA-DBRs were used in combination with RIfS to detect mercury ions (Hg21). The chemical selectivity of NAA-DBR platforms toward Hg21 was imparted by thiol-silane molecules (i.e., MPTMS) functionalized on the inner surface of nanopores. The performance of this sensing system was characterized by the correlation between the concentration of Hg21 and spectral shifts in the characteristic PSB, from which S, LLoD, and R2 were established to be 0.0115% μM21, 4.20 μM, and 0.994, respectively. The detection of Hg21 by NAA-DBRs can also be carried out based on visual sensing, as demonstrated by Chen et al. [80]. A palette of structurally colored NAADBRs was produced as a function of Tp (from 675 to 1170 s) and Tan (from 21 C to 3 C). As the effective medium of NAA-DBRs was altered by infiltration of ethanol, its characteristic interferometric color red-shifted. Based on the analysis of color changes and ΔOTeff measured before and after infiltration with ethanol by RIfS, it was determined that NAA-DBRs produced with Tp 5 1035 s and Tan 5 21 C gave the most intense color change and greatest ΔOTeff. These NAA-DBRs were then further explored as chemically selective visual sensing platforms for the detection of Hg21. Each sensing stage (i.e., functionalization of MPTMS and exposure to Hg21) was denoted by characteristic interferometric color changes. When chemically functionalized NAA-DBRs were exposed to different concentrations of Hg21, these NAA-DBRs underwent color changes measureable by RGB values. RGB values of NAA-DBRs as a function of the concentration of Hg21 ([Hg21]) revealed a linear correlation between the intensity of the blue and green channels in the RGB color and [Hg21] from 10 to 100 mM. The performance of this visual sensing tool for Hg21 detection was established to be a sensitivity and a low limit of detection of 0.81 a.u. μM21 and 1.25 μM for the blue channel and of 29.4 a.u. μM21 and 37.3 μM for the green channel, respectively.

Electrochemically engineered nanoporous photonic crystal structures

213

Ruiz-Clavijo et al. further explored the use of NAA-DBRs with periodic composition of high-porosity and low-porosity layers as colorimetric sensors [81]. The colorimetric sensing properties of these NAA-DBRs were assessed in terms of interferometric color shifts upon infiltration of nanopores with water and the background substrate. The color variations in NAA-DBRs were quantified by the CIE color space chromaticity diagram. The utilization of NAA-DBRs as visual sensing platform was also reported by Guo et al., where the exposure of these NAA-DBRs to ethanol induced a color change from blue to green [82]. These NAA-based Bragg stacks were also used as chemical sensors for in situ monitoring of organics with varied refractive indices by measuring their transmission spectra upon exposure to a series of alkanes (i.e., n-hexane, n-octane, and n-decane) and alcohols (i.e., anhydrous ethanol, 2-propanol, 1-butanol, and 1-hexanol). The resulting spectral shifts in the characteristic PSB in the transmission spectra of NAA-DBRs were correlated to the refractive index of media filling the nanopores and the sensitivity of the proposed NAA-DBR-based chemical sensor to alcohols and alkanes were 71.4 and 61.9 nm RIU21, respectively.

9.3.2 Nanoporous anodic alumina gradient-index filters The prominent structural feature of NAA-GIFs is the sinusoidal distribution of effective refractive index in depth, which can be produced by SPA (Fig. 9.5). As a result of the smooth variation of effective refractive index, the PSB of NAA-GIFs is well resolved and narrow-width, enhancing the sensitivity toward a change in the effective refractive index of these NAA-PC platforms [66,112]. Kumeria et al. fabricated NAA-GIFs by a two-step anodization process modified with pseudosinusoidal voltage profiles controlled by total charge (i.e., integration throughout time of current density) under potentiostatic conditions [83]. The sensitivity of these NAA-GIFs toward changes in their effective refractive index upon infiltration with D-glucose solutions was assessed by RIfS. As these NAA-GIFs were exposed to different concentrations of D-glucose solution (i.e., from 0.01 to 1.00 M), which is equivalent to a modification of refractive index from 1.333 to 1.363 RIU, the position of the characteristic PSB was red-shifted in the RIfS spectra. Described by the linear relationship between the spectral shift and the refractive index of media filling the nanopores, these NAA-GIF sensing platforms displayed a sensitivity for glucose of 4.93 nm M21 (i.e., 164 nm RIU21), with a LLoD of 0.01 M and a R2 of 0.998.

Figure 9.5 Characteristic nanoporous geometry, anodization profile, and optical properties of NAA-GIFs.

214

Handbook of Nanomaterials in Analytical Chemistry

Figure 9.6 Examples of the utilization of NAA-GIFs for optical sensing. (A-i) Representative RIfS spectrum of NAA-GIFs showing the spectral area to assess the sensing performance associated with drug-protein binding. (A-ii) Depiction of the sensing concept based on the adsorption and desorption of drug molecules to and from proteins. (A-iii) Real-time monitoring of effective optical thickness changes as a function of time (left) and drug concentrations (right). (A-iv) The sensing performance of protein-modified NAA-GIFs (Continued)

Electrochemically engineered nanoporous photonic crystal structures

215

L

These NAA-GIFs were suitable to be developed as visual sensing platforms as they displayed tunable interferometric colors by means of the anodization parameters and pore-widening time. The capability of these NAA-GIFs as colorimetric platforms was also demonstrated through the intense color change (i.e., green to red) resulted from the infiltration of nanopores with acetone. These NAA-GIFs produced by a modified two-step anodization were also utilized as chemically selective sensing platforms combined with RIfS for the detection of Hg21 in aqueous solutions, as demonstrated by Kumeria et al. [84] The chemical selectivity of these NAA-GIFs toward Hg21 was endowed by functionalization with MPTMS onto the inner surface of nanopores, as proven by a series of selectivity tests using analytical solutions containing interfering metal ions (i.e., Cu21, Pb21, Fe31). Upon exposure to various concentrations of Hg21, ranging from 1 to 750 μM, the position of the characteristic PSB of thiol-modified NAA-GIFs underwent red-shifts. This sensing system had a S of 0.072 nm μM21, a LLoD of 1 μM, a R2 of 0.992, and a linear working range from 1 to 100 μM, characterized by the linear fitting between the spectral shift and [Hg21]. The capability of the proposed sensing system for selective detection of Hg21 in real-life applications was also demonstrated through the exposure of NAA-GIF platforms to environmental samples such as tap and river water. Santos et al. produced NAA-GIFs by galvanostatic sinusoidal pulse anodization under mild conditions using sulfuric acid electrolyte to develop an optical sensing system for the study of drug pharmacokinetic profiles [65]. These NAA-GIFs were chemically functionalized with silane molecules and human serum albumin (HSA) molecules, which were immobilized onto the surface of APTES-modified NAA-GIFs via glutaraldehyde activation. HSA-modified NAA-GIFs were exposed to indomethacin, a model drug, and the binding events between immobilized HSA molecules and free indomethacin molecules were assessed in real-time by RIfS. The position of the characteristic PSB of HSA-modified NAA-GIFs was revealed to red-shift linearly with the concentration of drug molecules. The performance of this sensing system was characterized with S 5 0.63 nm mM21, LLoD 5 0.065 mM, and a R2 5 0.9935. As an extension of this study, Nemati et al. performed a systematic assessment of the binding affinity of HSA molecules to a set of drug molecules using optimized NAA-GIFs as sensing platforms in combination with RIfS [85] (Fig. 9.6A). These HSA-modified NAA-GIFs were exposed to various drug

exposed to different drug molecules characterized by spectral shift (left) and effective optical thickness change (right). (B-i) Apodized SPA profile used to produce NAA-GIFs, (B-ii) reflection and transmission spectra of NAA-GIFs as a function of pore-widening time. Source: (A) Reproduced from M. Nemati, A. Santos, C.S. Law, D. Losic, Assessment of binding affinity between drugs and human serum albumin using nanoporous anodic alumina photonic crystals. Anal. Chem. 88 (2016) 5971 5980, with copyright permission from American Chemical Society, 2016. (B) Reproduced from G. Macias, J. Ferre´-Borrull, J. Pallare`s, L.F. Marsal, 1-D nanoporous anodic alumina rugate filters by means of small current variations for real-time sensing applications, Nanoscale Res. Lett. 9 (2014) 315, with copyright permission from Springer, 2014.

216

Handbook of Nanomaterials in Analytical Chemistry

molecules (i.e., sulfadymethoxine, coumarin, warfarin, indomethacin, and salicylic acid) and the binding events were monitored in real time by RIfS. Spectral shifts in the characteristic PSB and ΔOTeff due to HSA drug interactions were linearly correlated to the concentration of drugs, where the slope of the linear fitting between the sensing parameters (i.e., PSB shift and ΔOTeff) and the concentration of drugs revealed that the drug affinity of HSA-modified NAA-GIFs was dependent on the sensing parameters. Marcias et al. also explored the sensing capabilities of NAA-GIFs by effective medium assessment using reflection spectroscopy [70] (Fig. 9.6B). These NAA-GIFs were produced by apodized sinusoidal pulse anodization with small current variation. The sinusoidally modulated effective medium of these NAA-GIFs was altered upon infiltration of nanopores with media of different refractive indices (i.e., air, ethanol, and deionized water), which resulted in a shift in the reflection band. This sensing system was able to detect small changes in refractive index, with a sensitivity of 48.8 nm RIU21.

9.3.3 Nanoporous anodic alumina optical microcavities NAA-μCVs are typically composed of two highly reflective mirrors (e.g., NAADBRs and NAA-GIFs), between which a physical cavity layer featuring straight cylindrical nanopores is sandwiched (Fig. 9.7). The cavity layer acts as a confinement element of electromagnetic waves by resonant recirculation of light within the NAA-PC structure. Wang et al. developed a humidity sensor using NAA-μCVs as sensing platforms [72]. NAA-μCVs were produced by insertion of a sandwiched layer of constant porosity as well as introduction of a phase shift into a stepwise pulse anodization profile. Spectral shifts upon exposure to water vapor were monitored as a function of time using UV-visible-NIR spectroscopy. Condensation of water vapor in the nanopores of NAA-μCVs modified the effective medium of these NAA-PC platforms, inducing a red-shift in the resonance band positon of 2.58 nm. This study established the foundation for the use of NAA-μCVs in gas sensing applications. Law et al. fabricated NAA-μCVs with a cavity layer featuring straight nanopores, which was sandwiched between two NAA-GIFs with sinusoidally modulated porosity in depth [73] (Fig. 9.8A). The transmission spectra of these NAA-μCVs presented PSBs with well-resolved and narrow resonance bands, which were precisely

Figure 9.7 Characteristic nanoporous geometry, anodization profile, and optical properties of NAA-μCVs.

Figure 9.8 Examples of sensing systems using NAA-μCVs as sensing platforms. (A-i) Fabrication of NAA-μCVs following a modified sinusoidal pulse anodization with a constant current density step to obtain illustrated nanoporous structure (right), (A-ii) cross-section SEM images showing the presence of cavity layer in between two NAA-GIFs, (A-iii) digital images showing the interferometric colors of NAA-μCVs as a function of anodization parameters, and (A-iv) transmission spectra of NAA-μCVs indicating the blue-shift of PSB as a function of pore-widening time. (B-i) The anodization profile used to engineer the nanoporous structure of defective NAA-PCs as shown by SEM image (right), (B-ii) the transmission spectra of defective NAA-PCs as a function of anodization parameter, and (Biii) the spectra of defective NAA-PCs modified with rhodamine B in terms of photoluminescence intensity and transmittance. Source: (A) Reproduced from C.S. Law, S.Y. Lim, A.D. Abell, L.F. Marsal, A. Santos, Structural tailoring of nanoporous anodic alumina optical microcavities for enhanced resonant recirculation of light, Nanoscale 10 (2018) 14139 14152, with copyright permission from The Royal Society of Chemistry, 2018. (B) Reproduced from Y.-Y. An, J. Wang, W.-M. Zhou, H.-X. Jin, J.-F. Li, C.-W. Wang, The preparation of high quality alumina defective photonic crystals and their application of photoluminescence enhancement, Superlattice Microst. 119 (2018) 1 8, with copyright permission from Elsevier, 2018.

218

Handbook of Nanomaterials in Analytical Chemistry

tuned by means of anodization parameters (i.e., cavity anodization time and cavity current density). These NAA-μCVs also exhibited vivid interferometric colors that correspond to the position of respective resonance band. Not only their optical properties in terms of spectral shift and interferometric colors can be readily used for chemical and biosensing applications, these NAA-μCVs are expected to have an outstanding sensing performance due to the narrow-width resonance bands with high-quality factor. Lee et al. fabricated NAA-μCVs using a graded-lattice profile by changing the effective lattice constant induced by pulsed cyclic anodization [71]. NAA-μCVs were immersed in a series of polar (i.e., water, anhydrous ethanol, and isopropyl alcohol) and nonpolar (i.e., n-hexane, cyclohexane, and trichloroethylene) analytical solutions. This effective medium modification was quantified by the linear red-shift in the position of the characteristic resonance band in the reflectance spectra as a function of the refractive index of infiltrating solution. The sensitivity of NAA-μCV-based refractometric sensor was determined to be 424.4 nm RIU21. These NAA-μCVs were also demonstrated to be a colorimetric tool as they displayed dynamic colorimetric responses upon infiltration with analytes of different refractive index such as air, water, isopropyl alcohol, cyclohexane, and trichloroethylene. The color changes were quantified as a function of lightness and chromaticity in the CIELab 19130 tristimulus color space. These NAA-μCV colorimetric sensors were able to detect refractive index differences of B0.01 RIU, with a perceptual color change over the whole visible range. An et al. prepared NAA-μCVs using a periodic pulse anodization technique modified with effective voltage-compensating strategy [113] (Fig. 9.8B). NAA-μCVs were chemically modified with rhodamine B by adsorption to form rhodamine B-NAA-μCVs composite sensing platforms. NAA-μCVs enhanced the PL intensity of the functional molecules absorbed onto the inner surface of NAA-μCVs. Although no sensing application was demonstrated, this system could potentially be used to develop PL-based sensors.

9.3.4 Other nanoporous anodic alumina photonic crystals sensing platforms Law et al. combined NAA-PC platforms with RIfS to develop a sensing system able to monitor in real time the formation of self-assembled monolayers of thiol molecules [114]. These NAA-PC platforms produced by sawtooth-like pulse anodization under mild conditions featured a characteristic PSB due to their modulated effective medium in a sawtooth-like manner, the spectral shifts of which were used as sensing parameter. These NAA-PC platforms were coated with gold and exposed to different concentration of 11-mercaptoundecanoic acid (11-MUA). As a result, the gold thiol interaction red shifted the position of the characteristic PSBs of these PCs linearly with increasing concentration of 11-MUA. Based on the linear correlation between these two parameters, this sensing system had a performance of S 5 8.88 nm mM21, LLoD 5 0.3125 mM, and R2 5 0.90 within the working range from 0.3125 to 1.25 mM. The formation of self-assembled monolayers of thiol

Electrochemically engineered nanoporous photonic crystal structures

219

molecules on these gold-coated NAA-PC platforms was also found to follow a Langmuir isotherm-binding model. Yan et al. carried out effective medium assessment on NAA-PCs with sinusoidally modulated nanopores produced by two-step anodization using transmission spectroscopy in order to explore their feasibility as a chemical sensor [115]. The nanopores of these PCs were infiltrated with a series of analytes, including water, ethyl alcohol, ethylene glycol, and glycerol. This change in effective refractive index of these PCs upon infiltration was translated into a shift in the position of PSB, which followed a linear trend with increasing refractive index of the infiltrating media. The sensitivity of these PC platforms to effective medium changes was identified to be 108.5 nm RIU21. Shang et al. explored the fabrication of NAA-PCs by incorporating compensation voltage mode into a twostep anodization [116]. These NAA-PC platforms presented ultra-narrow PSB, the position of which was used as sensing parameter in the detection of ethanol vapor. The position of the PSB of these PC platforms underwent a red-shift of 66 nm, as they were exposed to increasing concentration of anhydrous ethanol gas (i.e., from 0 to 13.72 mmol L21). This linear red-shift was also observed when the exposure time of NAA-PCs to saturated ethanol vapor increased. Using the same anodization approach to fabricate NAA-PCs, Shang et al. used these PC platforms to monitor the adsorption of organic molecules via capillary condensation [117]. The adsorption of ethanol, methanol, acetone, and toluene in both gas and liquid states was monitored through shifts in the characteristic PSB of these PC structures. Their observations indicate that, upon saturation of condensed analyte molecules in the nanopores of NAA-PCs, the position of the PSB red-shifts, whereas the transmission intensity is reduced.

9.4

Conclusions

This chapter provides a comprehensive review on the recent developments of chemical and biosensing systems based on NAA-PCs, demonstrating their promising potential and broad applicability to realize unique and innovative sensing concepts and devices. NAA-PCs are excellent sensing platforms due to their versatile nanoporous geometry and surface chemistry, which can be precisely engineered to tune their optical and chemical properties. The effective medium of NAA-PCs can be modulated in a multidimensional manner to control light in different ways and utilize light matter interactions at the nanoscale to achieve high sensitivity for different sensing applications. Pioneering studies demonstrated the potential of NAA-PCs for optical applications and recent developments of rationally designed pulse-like anodization strategies have boosted the applicability of multidimensional NAA-PCs for chemical and biosensing applications, providing new opportunities to develop state-of-the-art optical systems based on different sensing principles (e.g., colorimetry, reflection, transmission, and photoluminescence). Electrochemical engineering is an attractive approach for the production of NAA-PCs with finely tuned optical properties across the spectral regions, from UV to IR. Owing to the inherent limitations of NAA such as low refractive index and

220

Handbook of Nanomaterials in Analytical Chemistry

limited range of lattice constants, more theoretical simulations and experimental investigations should be performed for the design of novel anodization approaches and unique NAA-PC architectures with exceptional optical and sensing properties. With enhanced chemical selectivity endowed by new functionalization approaches, NAA-PCs can be integrated with other technologies such as microfabrication and microfluidics into fully functional optical sensing devices and lab-on-a-chip systems with practicality and optimal performances for real-world chemical and biosensing applications.

References [1] J. Homola, S.S. Yee, G. Gauglitz, Surface plasmon resonance sensors: review, Sens. Actuators B Chem. 54 (1999) 3 15. [2] J.H. Holtz, S.A. Asher, Polymerized colloidal crystal hydrogel films as intelligent chemical sensing materials, Nature 389 (1997) 829 832. [3] T.A. Dickinson, J. White, J.S. Kauer, D.R. Walt, A chemical-detecting system based on a cross-reactive optical sensor array, Nature 382 (1996) 697 700. [4] J.K. Rosenstein, M. Wanunu, C.A. Merchant, M. Drndic, K.L. Shepard, Integrated nanopore sensing platform with sub-microsecond temporal resolution, Nat. Methods 9 (2012) 487 492. [5] B.N. Miles, A.P. Ivanov, K.A. Wilson, F. Dogan, D. Japrung, J.B. Edel, Single molecule sensing with solid-state nanopores: novel materials, methods, and applications, Chem. Soc. Rev. 42 (2013) 15 28. [6] K. Hotta, A. Yamaguchi, N. Teramae, Nanoporous waveguide sensor with optimized nanoarchitectures for highly sensitive label-free biosensing, ACS Nano 6 (2012) 1541 1547. [7] A. Dhathathreyan, Real-time monitoring of invertase activity immobilized in nanoporous aluminum oxide, J. Phys. Chem. B 115 (2011) 6678 6682. [8] D.K. Kim, D.M. Kim, S.M. Yoo, S.Y. Lee, Controllable gold-capped nanoporous anodic alumina chip for label-free, specific detection of bacterial cells, RSC Adv. 7 (2017) 18815 18820. [9] S.W. Kim, J.S. Lee, S.W. Lee, B.H. Kang, J.B. Kwon, O.S. Kim, et al., Easy-tofabricate and high-sensitivity LSPR type specific protein detection sensor using AAO nano-pore size control, Sensors 17 (2017) 856. [10] X. Fan, Q. Hao, T. Qiu, Controlled assembly of plasmonic nanostructures templated by porous anodic alumina membranes. Cham in: C. Geddes (Ed.), Reviews in Plasmonics 2015, vol. 2015, Springer, 2016, pp. 249 274. [11] M. Celik, S. Altuntas, F. Buyukserin, Fabrication of nanocrater-decorated anodic aluminum oxide membranes as substrates for reproducibly enhanced SERS signals, Sens. Actuators B Chem. 255 (2018) 2871 2877. [12] B.M. Tran, N.N. Nam, S.J. Son, N.Y. Lee, Nanoporous anodic aluminum oxide internalized with gold nanoparticles for on-chip PCR and direct detection by surfaceenhanced Raman scattering, Analyst 143 (2018) 808 812. [13] L.M. Ferro, S.G. Lemos, M. Ferreira, F. Trivinho-Strixino, Use of multivariate analysis on Fabry-Pe´rot interference spectra of nanoporous anodic alumina (NAA) for optical sensors purposes, Sens. Actuators B Chem. 248 (2017) 718 723.

Electrochemically engineered nanoporous photonic crystal structures

221

[14] A. Santos, V.S. Balderrama, M. Alba, P. Formentı´n, J. Ferre´-Borrull, J. Pallare`s, et al., Nanoporous anodic alumina barcodes: toward smart optical biosensors, Adv. Mater. 24 (2012) 1050 1054. [15] C.S. Law, S.Y. Lim, A.D. Abell, A. Santos, Real-time binding monitoring between human blood proteins and heavy metal ions in nanoporous anodic alumina photonic crystals, Anal. Chem. 90 (2018) 10039 10048. [16] C.S. Law, G.M. Sylvia, M. Nemati, J. Yu, D. Losic, A.D. Abell, et al., Engineering of surface chemistry for enhanced sensitivity in nanoporous interferometric sensing platforms, ACS Appl. Mater. Inter. 9 (2017) 8929 8940. [17] C. Lo´pez, Materials aspects of photonic crystals, Adv. Mater. 15 (2003) 1680 1704. [18] E. Yablonovitch, Inhibited spontaneous emission in solid-state physics and electronics, Phys. Rev. Lett. 58 (1987) 2059. [19] S. John, Strong localization of photons in certain disordered dielectric superlattices, Phys. Rev. Lett. 58 (1987) 2486. [20] Y. Xia, B. Gates, Z.-Y. Li, Self-assembly approaches to three-dimensional photonic crystals, Adv. Mater. 13 (2001) 409 413. [21] S. Pace, R.B. Vasani, W. Zhao, S. Perrier, N.H. Voelcker, Photonic porous silicon as a pH sensor, Nanoscale Res. Lett. 9 (2014) 420. [22] S.N. Aisyiyah Jenie, S.E. Plush, N.H. Voelcker, Singlet oxygen detection on a nanostructured porous silicon thin film via photonic luminescence enhancements, Langmuir 33 (2017) 8606 8613. [23] K.A. Kilian, L.M.H. Lai, A. Magenau, S. Cartland, T. Bo¨cking, N. Di Girolamo, et al., Smart tissue culture: in situ monitoring of the activity of protease enzymes secreted from live cells using nanostructured photonic crystals, Nano Lett. 9 (2009) 2021 2025. [24] V.S.-Y. Lin, K. Motesharei, K.-P.S. Dancil, M.J. Sailor, M.R. Ghadiri, A porous silicon-based optical interferometric biosensor, Science 278 (1997) 840 843. [25] A. Janshoff, K.-P.S. Dancil, C. Steinem, D.P. Greiner, V.S.-Y. Lin, C. Gurtner, et al., Macroporous p-Type silicon Fabry Perot layers. Fabrication, characterization, and applications in biosensing, J. Am. Chem. Soc. 120 (1998) 12108 12116. [26] W. Lee, S.-J. Park, Porous anodic aluminum oxide: anodization and templated synthesis of functional nanostructures, Chem. Rev. 114 (2014) 7487 7556. [27] A. Santos, Nanoporous anodic alumina photonic crystals: fundamentals, developments and perspectives, J. Mater. Chem. C 5 (2017) 5581 5599. [28] H. Masuda, F. Hasegwa, S. Ono, Self-ordering of cell arrangement of anodic porous alumina formed in sulfuric acid solution, J. Electrochem. Soc. 144 (1997) L127 L130. [29] H. Masuda, K. Yada, A. Osaka, Self-ordering of cell configuration of anodic porous alumina with large-size pores in phosphoric acid solution, Jpn. J. Appl. Phys 37 (1998) L 1340 L1342. [30] D. Losic, A. Santos (Eds.), Nanoporous Alumina: Fabrication, Structure, Properties and Applications, vol. 219, Springer International Publishing, Switzerland, 2015. [31] W. Theiβ, S. Henkel, M. Arntzen, Connecting microscopic and macroscopic properties of porous media: choosing appropriate effective medium concepts, Thin Solid Films 255 (1995) 177 180. [32] A. Santos, T. Kumeria, D. Losic, Nanoporous anodic alumina: a versatile platform for optical biosensors, Materials 7 (2014) 4297 4320. [33] A.M.M. Jani, D. Losic, N.H. Voelcker, Nanoporous anodic aluminium oxide: advances in surface engineering and emerging applications, Prog. Mater. Sci. 58 (2013) 636 704.

222

Handbook of Nanomaterials in Analytical Chemistry

[34] T. Kumeria, A. Santos, D. Losic, Nanoporous anodic alumina platforms: engineered surface chemistry and structure for optical sensing applications, Sensors 14 (2014) 11878 11918. [35] H. Masuda, M. Ohya, H. Asoh, M. Nakao, M. Nohtomi, T. Tamamura, Photonic crystal using anodic porous alumina, Jpn. J. Appl. Phys. 38 (1999) L 1403 L1405. [36] H. Masuda, M. Ohya, K. Nishio, H. Asoh, M. Nakao, M. Nohtomi, et al., Photonic band gap in anodic porous alumina with extremely high aspect ratio formed in phosphoric acid solution, Jpn. J. Appl. Phys. 39 (2000) L 1039 L1041. [37] H. Masuda, M. Ohya, H. Asoh, K. Nishio, Photonic band gap in naturally occurring ordered anodic porous alumina, Jpn. J. Appl. Phys. 40 (2001) L1217 L1219. [38] J. Choi, Y. Luo, R.B. Wehrspohn, R. Hillebrand, J. Schilling, U. Go¨sele, Perfect twodimensional porous anodic alumina photonic crystal with duplex oxide layers, J. Appl. Phys. 8 (2003) 4757 4762. [39] R. Kondo, T. Kikuchi, S. Natsui, R.O. Suzuki, Fabrication of self-ordered porous alumina via anodizing in sulfate solutions, Mater. Lett. 183 (2016) 285 289. [40] O. Nishinaga, T. Kikuchi, S. Natsui, R.O. Suzuki, Rapid fabrication of self-ordered porous alumina with 10-/ sub-10-nm-scale nanostructures by selenic acid anodizing, Sci. Rep. 3 (2013) 2748. [41] A. Takenaga, T. Kikuchi, S. Natsui, R.O. Suzuki, Exploration for the self-ordering of porous alumina fabricated via anodizing in etidronic acid, Electrochim. Acta 211 (2016) 515 523. [42] T. Kikuchi, T. Yamamoto, R.O. Suzuki, Growth behavior of anodic porous alumina formed in malic acid solution, Appl. Surf. Sci. 284 (2013) 907 913. [43] S. Akiya, T. Kikuchi, S. Natsui, N. Sakaguchi, R.O. Suzuki, Self-ordered porous alumina fabricated via phosphonic acid anodizing, Electrochim. Acta 190 (2016) 471 479. [44] S. Akiya, T. Kikuchi, S. Natsui, R.O. Suzuki, Optimum exploration for the selfordering of anodic porous alumina formed via selenic acid anodizing, J. Electrochem. Soc. 162 (2015) E244 E250. [45] A. Takenaga, T. Kikuchi, S. Natsui, R.O. Suzuki, Self-ordered aluminum anodizing in phosphonoacetic acid and its structural coloration, ECS Solid State Lett. 4 (2015) P55 P58. [46] T. Kikuchi, O. Nishinaga, S. Natsui, R.O. Suzuki, Fabrication of self-ordered porous alumina via etidronic acid anodizing and structural color generation from submicrometer-scale dimple array, Electrochim. Acta 156 (2015) 235 243. [47] D. Nakajima, T. Kikuchi, S. Natsui, R.O. Suzuki, Growth behavior of anodic oxide formed by aluminum anodizing in glutaric and its derivative acid electrolytes, Appl. Surf. Sci. 321 (2014) 364 370. [48] T. Kikuchi, O. Nishinaga, S. Natsui, R.O. Suzuki, Self-ordering behavior of anodic porous alumina via selenic acid anodizing, Electrochim. Acta 137 (2014) 728 735. [49] T. Kikuchi, D. Nakajima, J. Kawashima, S. Natsui, R.O. Suzuki, Fabrication of anodic porous alumina via anodizing in cyclic oxocarbon acids, Appl. Surf. Sci. 313 (2014) 276 285. [50] T. Kikuchi, T. Yamamoto, S. Natsui, R.O. Suzuki, Fabrication of anodic porous alumina by squaric acid anodizing, Electrochim. Acta 123 (2014) 14 22. [51] O. Jessensky, F. Mu¨ller, U. Go¨sele, Self-organized formation of hexagonal pore arrays in anodic alumina, Appl. Phys. Lett. 72 (1998) 1173 1175. [52] W. Lee, K. Nielsch, U. Go¨sele, Self-ordering behavior of nanoporous anodic aluminum oxide (AAO) in malonic acid anodization, Nanotechnology 18 (2007) 475713.

Electrochemically engineered nanoporous photonic crystal structures

223

[53] V. Vega, J. Garcı´a, J.M. Montero-Moreno, B. Hernando, J. Bachmann, V.M. Prida, et al., Unveiling the hard anodization regime of aluminum: insight into nanopores selforganization and growth mechanism, ACS Appl. Mater. Interfaces 7 (2015) 28682 28692. [54] J.P. O’Sullivan, G.C. Wood, The morphology and mechanism of formation of porous anodic films on aluminium, Proc. R. Soc. Lond. A 317 (1970) 511 543. [55] G.D. Sulka, K.G. Parkoła, Temperature influence on well-ordered nanopore structures grown by anodization of aluminium in sulphuric acid, Electrochim. Acta 52 (2007) 1880 1888. [56] R.C. Furneaux, W.R. Rigby, A.P. Davidson, The formation of controlled-porosity membranes from anodically oxidized aluminium, Nature 337 (1989) 147 149. [57] W. Cheng, M. Steinhart, U. Go¨sele, R.B. Wehrspohn, Tree-like alumina nanopores generated in a non-steady-state anodization, J. Mater. Chem. 17 (2007) 3493 3495. [58] J.M. Montero-Moreno, M. Belenguer, M. Sarret, C.M. Mu¨ller, Production of alumina templates suitable for electrodeposition of nanostructures using stepped techniques, Electrochim. Acta 54 (2009) 2529 2535. [59] W. Lee, J.-C. Kim, Highly ordered porous alumina with tailor-made pore structures fabricated by pulse anodization, Nanotechnology 21 (2010) 485304. [60] W. Lee, K. Schwirn, M. Steinhart, E. Pippel, R. Scholz, U. Go¨sele, Structural engineering of nanoporous anodic aluminium oxide by pulse anodization of aluminium, Nat. Nanotechnol. 3 (2008) 234 239. [61] W. Lee, R. Scholz, U. Go¨sele, A continuous process for structurally well-defined AlO nanotubes based on pulse anodization of aluminium, Nano Lett. 8 (2008) 2155 2160. [62] W. Lee, J.C. Kim, U. Go¨sele, Spontaneous current oscillations during hard anodization of aluminum under potentiostatic conditions, Adv. Funct. Mater. 19 (2009) 1 7. [63] G.D. Sulka, K. Hnida, Distributed Bragg reflector based on porous anodic alumina fabricated by pulse anodization, Nanotechnology 23 (2012) 075303. [64] J. Martı´n, M. Martı´n-Gonza´lez, J.F. Ferna´ndez, O. Caballero-Calero, Ordered threedimensional interconnected nanoarchitectures in anodic porous alumina, Nat. Commun. 5 (2014) 5130. [65] A. Santos, J.H. Yoo, C.V. Rohatgi, T. Kumeria, Y. Wang, D. Losic, Realisation and advanced engineering of true optical rugate filters based on nanoporous anodic alumina by sinusoidal pulse anodisation, Nanoscale 8 (2016) 1360 1373. [66] E. Lorenzo, C.J. Oton, N.E. Capuj, M. Ghulinyan, D. Navarro-Urrios, Z. Gaburro, et al., Porous silicon-based rugate filters, Appl. Opt. 44 (2005) 5415 5421. [67] A. Santos, C.S. Law, D.W.C. Lei, T. Pereira, D. Losic, Fine tuning of optical signals in nanoporous anodic alumina photonic crystals by apodized sinusoidal pulse anodisation, Nanoscale 8 (2016) 18360 18375. [68] S.Y. Lim, C.S. Law, L.F. Marsal, A. Santos, Engineering of hybrid nanoporous anodic alumina photonic crystals by heterogeneous pulse anodization, Sci. Rep. 8 (2018) 9455. [69] C.S. Law, S.Y. Lim, A. Santos, Fine tuning of transmission features in nanoporous anodic alumina distributed Bragg reflectors, Proc. SPIE Nanophoton. Aust. 10456 (2018) 1045659. [70] G. Macias, J. Ferre´-Borrull, J. Pallare`s, L.F. Marsal, 1-D nanoporous anodic alumina rugate filters by means of small current variations for real-time sensing applications, Nanoscale Res. Lett. 9 (2014) 315. [71] J. Lee, K. Bae, G. Kang, M. Choi, S. Baek, D.-S. Yoo, et al., Graded-lattice AAO photonic crystal heterostructure for high Q refractive index sensing, RSC Adv. 5 (2015) 71770 71777.

224

Handbook of Nanomaterials in Analytical Chemistry

[72] Y. Wang, Y. Chen, T. Kumeria, F. Ding, A. Evdokiou, D. Losic, et al., Facile synthesis of optical microcavities by a rationally designed anodization approach: tailoring photonic signals by nanopore structure, ACS Appl. Mater. Inter. 7 (2015) 9879 9888. [73] C.S. Law, S.Y. Lim, A.D. Abell, L.F. Marsal, A. Santos, Structural tailoring of nanoporous anodic alumina optical microcavities for enhanced resonant recirculation of light, Nanoscale 10 (2018) 14139 14152. [74] C.S. Law, S.Y. Lim, R.M. Macalincag, A.D. Abell, A. Santos, Light-confining nanoporous anodic alumina microcavities by apodized stepwise pulse anodization, ACS Appl. Nano Mater. 1 (2018) 4418 4434. [75] A. Santos, T. Pereira, C.S. Law, D. Losic, Rational engineering of nanoporous anodic alumina optical bandpass filters, Nanoscale 8 (2016) 14846 14857. [76] Sukarno, C.S. Law, A. Santos, Realisation and optical engineering of linear variable bandpass filters in nanoporous anodic alumina photonic crystals, Nanoscale 9 (2017) 7541 7550. [77] Y. Chen, A. Santos, Y. Wang, T. Kumeria, C. Wang, J. Li, et al., Interferometric nanoporous anodic alumina photonic coatings for optical sensing, Nanoscale 7 (2015) 7770 7779. [78] Y. Chen, A. Santos, Y. Wang, T. Kumeria, J. Li, C. Wang, et al., Biomimetic nanoporous anodic alumina distributed Bragg reflectors in the form of films and microsized particles for sensing applications, ACS Appl. Mater. Inter. 7 (2015) 19816 19824. [79] T. Kumeria, A. Santos, M.M. Rahman, J. Ferre´-Borrull, L.F. Marsal, D. Losic, Advanced structural engineering of nanoporous photonic structures: tailoring nanopore architecture to enhance sensing properties, ACS Photon. 1 (2014) 1298 1306. [80] Y. Chen, A. Santos, Y. Wang, T. Kumeria, D. Ho, J. Li, et al., Rational design of photonic dust from nanoporous anodic alumina films: a versatile photonic nanotool for visual sensing, Sci. Rep. 5 (2015) 12893. [81] A. Ruiz-Clavijo, Y. Tsurimaki, O. Caballero-Calero, G. Ni, G. Chen, S.V. Boriskina, et al., Engineering a full gamut of structural colors in all-dielectric mesoporous network metamaterials, ACS Photon. 5 (2018) 2120 2128. [82] D.-L. Guo, L.-X. Fan, F.-H. Wang, S.-Y. Huang, X.-W. Zou, Porous anodic aluminum oxide Bragg stacks as chemical sensors., J. Phys. Chem. C 112 (2008) 17952 17956. [83] T. Kumeria, M.M. Rahman, A. Santos, J. Ferre´-Borrull, L.F. Marsal, D. Losic, Structural and optical nanoengineering of nanoporous anodic alumina rugate filters for real-time and label-free biosensing applications, Anal. Chem. 86 (2014) 1837 1844. [84] T. Kumeria, M.M. Rahman, A. Santos, J. Ferre´-Borrull, L.F. Marsal, D. Losic, Nanoporous anodic alumina rugate filters for sensing of ionic mercury: toward environmental point-of-analysis systems, ACS Appl. Mater Inter. 6 (2014) 12971 12978. [85] M. Nemati, A. Santos, C.S. Law, D. Losic, Assessment of binding affinity between drugs and human serum albumin using nanoporous anodic alumina photonic crystals, Anal. Chem. 88 (2016) 5971 5980. [86] C.S. Law, S.Y. Lim, A. Santos, On the precise tuning of optical filtering features in nanoporous anodic alumina distributed Bragg reflectors, Sci. Rep. 8 (2018) 4642. [87] A. Debrassi, A. Ribbera, W.M. de Vos, T. Wennekes, H. Zuilhof, Stability of (bio) functionalized porous aluminum oxide, Langmuir 30 (2014) 1311 1320. [88] M. Norek, A. Krasi´nski, Controlling of water wettability by structural and chemical modification of porous anodic alumina (PAA): towards super-hydrophobic surfaces, Surf. Coat. Tech. 276 (2015) 464 470. [89] A. Marek, W. Tang, S. Milikisiyants, A.A. Nevzorov, A.I. Smirnov, Nanotube array method for studying lipid-induced conformational changes of a membrane protein by solid-state NMR, Biophys. J. 108 (2015) 5 9.

Electrochemically engineered nanoporous photonic crystal structures

225

[90] C. Eckstein, L.K. Acosta, L. Pol, E. Xifre´-Pe´rez, J. Pallares, J. Ferre´-Borrull, et al., Nanoporous anodic alumina surface modification by electrostatic, covalent, and immune complexation binding investigated by capillary filling, ACS Appl. Mater. Inter. 10 (2018) 10571 10579. [91] M. Porta-i-Batalla, C. Eckstein, E. Xifre´-Pe´rez, P. Formentı´n, J. Ferre´-Borrull, L.F. Marsal, Sustained, controlled and stimuli-responsive drug release systems based on nanoporous anodic alumina with layer-by-layer polyelectrolyte, Nanoscale Res. Lett. 11 (2016) 372. [92] S. Hou, J. Wang, C.R. Martin, Template-synthesized DNA nanotubes, J. Am. Chem. Soc. 127 (2005) 8586 8587. [93] S. Hou, J. Wang, C.R. Martin, Template-synthesized protein nanotubes, Nano Lett. 5 (2005) 231 234. [94] C. Sheng, S. Wijeratne, C. Cheng, G.L. Baker, M.L. Bruening, Facilitated ion transport through polyelectrolyte multilayer films containing metal-binding ligands, J. Membrane Sci. 459 (2014) 169 176. [95] M. Norek, M. Putkonen, W. Zaleszczyk, B. Budner, Z. Bojar, Morphological, structural and optical characterization of SnO2 nanotube arrays fabricated using anodic alumina (AAO) template-assisted atomic layer deposition, Mater. Charact. 136 (2018) 52 59. [96] V. Vega, L. Gelde, A. Gonza´lez, V. Prida, B. Hernando, J. Benavente, Diffusive transport through surface functionalized nanoporous alumina membranes by atomic layer deposition of metal oxides, J. Ind. Eng. Chem. 52 (2017) 66 72. [97] W.J. Stepniowski, M. Moneta, K. Karczewski, M. Michalska-Domanska, T. Czujko, J. M. Mol, et al., Fabrication of copper nanowires via electrodeposition in anodic aluminum oxide templates formed by combined hard anodizing and electrochemical barrier layer thinning, J. Electroanal. Chem. 809 (2018) 59 66. [98] N. Ahmad, M. Awais, S.A. Shah, I. Ahmed, N. Jabeen, A. Majid, et al., Influence of voltage variation on structure and magnetic properties of Co1-xSnx (X 5 0.3 0.7) nanowire alloys in alumina by electrochemical deposition, Appl. Phys. A: Mater. 123 (2017) 65. [99] S. Agarwal, S. Hashmi, B. Nandan, A.K. Patra, R.P. Singh, J.A. Chelvane, et al., Structure and magnetic properties of electrodeposited CoPtP/Pt multilayer nanowires, Chem. Phys. Lett. 684 (2017) 378 382. [100] A. Kumar, A. Sanger, A. Kumar, R. Chandra, Highly sensitive and selective CO gas sensor based on a hydrophobic SnO2/CuO bilayer, RSC Adv. 6 (2016) 47178 47184. [101] M. Salerno, A. Shayganpour, B. Salis, S. Dante, Surface-enhanced Raman scattering of self-assembled thiol monolayers and supported lipid membranes on thin anodic porous alumina, Beilstein J. Nanotech. 8 (2017) 74 81. [102] S. Simovic, D. Losic, K. Vasilev, Controlled drug release from porous materials by plasma polymer deposition, Chem. Commun. 46 (2010) 1317 1319. [103] S. Simovic, K. Diener, A. Bachhuka, K. Kant, D. Losic, J. Hayball, et al., Controlled release and bioactivity of the monoclonal antibody rituximab from a porous matrix: a potential in situ therapeutic device, Mater. Lett. 130 (2014) 210 214. [104] H. Wu, Y. Higaki, A. Takahara, Molecular self-assembly of one-dimensional polymer nanostructures in nanopores of anodic alumina oxide templates, Prog. Polym. Sci. 77 (2018) 95 117. [105] T. Du, S. Ma, X. Pei, S. Wang, F. Zhou, Bio-inspired design and fabrication of micro/ nano-brush dual structural surfaces for switchable oil adhesion and antifouling, Small 13 (2017) 1602020.

226

Handbook of Nanomaterials in Analytical Chemistry

[106] S. Entani, M. Honda, I. Shimoyama, S. Li, H. Naramoto, T. Yaita, et al., Effective adsorption and collection of cesium from aqueous solution using graphene oxide grown on porous alumina, Jpn. J. Appl. Phys. 57 (2018) 04FP04. [107] S.Y. Lim, C.S. Law, M. Markovic, J.K. Kirby, A.D. Abell, A. Santos, Engineering the slow photon effect in photoactive nanoporous anodic alumina gradient-index filters for photocatalysis, ACS Appl. Mater. Inter. 10 (2018) 24124 24136. [108] S. Ni, X. Li, P. Yang, S. Ni, F. Hong, T.J. Webster, Enhanced apatite-forming ability and antibacterial activity of porous anodic alumina embedded with CaO-SiO2-Ag2O bioactive materials, Mat. Sci. Eng. C-Mater. 58 (2016) 700 708. [109] W. Wang, N. Li, X. Li, W. Geng, S. Qiu, Synthesis of metallic nanotube arrays in porous anodic aluminum oxide template through electroless deposition, Mater. Res. Bull. 41 (2006) 1417 1423. [110] Y.E. Silina, T.A. Kychmenko, M. Koch, Nanoporous anodic aluminum oxide films for UV/vis detection of noble and non-noble metals, Anal. Methods 8 (2016) 45 51. [111] A. Santos, T. Kumeria, D. Losic, Nanoporous anodic aluminum oxide for chemical sensing and biosensors, TrAC Trend. Anal. Chem. 44 (2013) 25 38. [112] S. Ilyas, T. Bo¨cking, K. Kilian, P. Reece, J. Gooding, K. Gaus, et al., Porous silicon based narrow line-width rugate filters, Opt. Mater. 29 (2007) 619 622. [113] Y.-Y. An, J. Wang, W.-M. Zhou, H.-X. Jin, J.-F. Li, C.-W. Wang, The preparation of high quality alumina defective photonic crystals and their application of photoluminescence enhancement, Superlattice Microst. 119 (2018) 1 8. [114] C.S. Law, A. Santos, M. Nemati, D. Losic, Structural engineering of nanoporous anodic alumina photonic crystals by sawtooth-like pulse anodization, ACS Appl. Mater. Inter. 8 (2016) 13542 13554. [115] P. Yan, G.T. Fei, G.L. Shang, B. Wu, L. De Zhang, Fabrication of one-dimensional alumina photonic crystals with a narrow band gap and their application to highsensitivity sensors, J. Mater. Chem. C 1 (2013) 1659 1664. [116] G.L. Shang, G.T. Fei, Y. Zhang, P. Yan, S.H. Xu, L. De Zhang, Preparation of narrow photonic bandgaps located in the near infrared region and their applications in ethanol gas sensing, J. Mater. Chem. C 1 (2013) 5285 5291. [117] G. Shang, G. Fei, Y. Li, L. Zhang, Influence of dielectrics with light absorption on the photonic bandgap of porous alumina photonic crystals, Nano Res. 9 (2016) 703 712.

Further reading H. Masuda, K. Fukuda, Ordered metal nanohole arrays made by a two-step replication of honeycomb structures of anodic alumina, Science 268 (1995) 1466 1468.

Pressure and temperature optical sensors: luminescence of lanthanide-doped nanomaterials for contactless nanomanometry and nanothermometry

10

Marcin Runowski ´ Poland Faculty of Chemistry, Adam Mickiewicz University, Poznan,

10.1

Introduction

Alike pressure and temperature are fundamental physical quantities, state functions affecting physicochemical properties of the materials, their measurements, accurate and precise determination, are crucial for both scientific and industrial applications. Conventional methods determining them are based on the use of different kinds of manometers in the case of pressure, and metallic/liquid thermometers, thermocouples, pyrometers, etc., in case of temperature measurements. However, both methods require a physical contact with the measured object and/or cannot be used for the exact determination of local pressure/temperature, in the submicro-sized areas. These issues can be resolved by the use of contactless nanomanometers and nanothermometers (NTMs), working based on the remote measurements of pressure/temperature-dependent luminescence of lanthanide-doped nanomaterials, acting as optical nanosensors of pressure and temperature. Small, functional materials (nanomaterials) are currently extensively studied due to their unique optoelectronic, magnetic, and structural properties [1
18]. Lanthanide (Ln31)-based luminescent nanoparticles (NPs) exhibit multicolor emission under ultraviolet (UV) and near-infrared (NIR) [energy upconversion (UC)] irradiation, long radiative lifetimes, and narrow emission bands corresponding to 4f
4f transition within Ln31 ions, and related to the crystal-field effects and shielding of 4f electrons by 5s and 5p ones [1,2,4
6,19
22]. In general, inorganic crystals doped with Ln31 ions are resistant to high temperature and photodegradation [1,5,23]. The inorganic fluorides, phosphates, borates, and vanadates are good hosts for Ln31 ions, as they can crystallize in water, microparticle and NP, forming colloidal solutions, as well as exhibit intense luminescence, thanks to the relatively low phonon energy of their crystal lattices [1,2,5,24,25].

Handbook of Nanomaterials in Analytical Chemistry. DOI: https://doi.org/10.1016/B978-0-12-816699-4.00010-4 Copyright © 2020 Elsevier Inc. All rights reserved.

228

Handbook of Nanomaterials in Analytical Chemistry

However, their most favorable feature can be an effective energy UC, leading to anti-Stokes emission in a visible range, after excitation with an NIR light (e.g., at B800, 975, and 1550 nm) [26
28]. The NIR light, commonly used for generation of UC luminescence, is highly penetrable for many media, which is very important for various bioapplications. Thanks to the high absorption cross section of Yb31 in the NIR range (B975 nm), Yb31 ions act as efficient sensitizers (light-harvesting ions), after their excitation with NIR laser. They transfer the excitation energy to the neighboring emitting ions, for example, Er31, Ho31, Tm31 (luminescence activators), pumping their excited states via energy transfer upconversion (ETU) processes [1,2,26,27]. Upconverting nanomaterials reveal many advantages in comparison to quantum dots and organic fluorophores (excited with UV light, which is harmful for biological systems). UC NPs can be excited with low-energy NIR photons, they exhibit relatively low cytotoxicity, narrow emission bands, long luminescence lifetimes, and resistance to photobleaching, thermal decomposition, and oxidation processes [4,5,21
23]. Thanks to the mentioned favorable properties, the UC NPs are commonly used in various applications, for example, modern labeling techniques (multimodal tracers), biomedical applications (bioimaging, photodynamic therapy), forensic sciences (detection of fingerprints, security markers—barcoding), nanosensors (nanomanometry, nanothermometry), photovoltaics (solar cells), and optical fibers [1,2,27
34]. In order to provide efficient UC luminescence of the material, it is crucial to select the appropriate crystallographic structure (usually with low local symmetry of the Ln31 ion), that is, host matrix for the Ln31 dopant ions, and ensure high crystallinity of the final material. The symmetry of the local crystal field influences the luminescence of Ln31 ions embedded in the nanocrystals. This is because of the Laporte selection rules, which forbid the electric dipole transitions between the states of the same parity, especially for the centrosymmetric systems (if they are observable, their intensity is relatively low) [19,21,22]. Materials composed of the particles with different structure, phase, or symmetry doped with the same Ln21/31 ions, may have different energy difference between their electronic states, thermalized levels, for example, fluorides versus oxides, β-NaYF4 versus α-NaYF4, and so forth [25,28,29]. The Ln31-doped, noncentrosymmetric, inorganic fluorides such as β-NaYF4 or β-NaLuF4, having a very low phonon energy of their crystal lattice (to limit multiphonon relaxation processes) seem to be good candidates as effective UC luminescent materials [2,25,29]. Because of the high sensitivity of Ln21/31 ions to the alterations of bonds geometry and symmetry of local coordination environment (site symmetry) of the emitting ion, the Ln21/31-doped NPs can be applied in nanomanometry, as pressure sensors [1,2,34]. As some Ln21/31-doped materials are very sensitive to temperature alterations, their luminescence properties may change with temperature significantly. Hence, the similar optical effects can be used in nanothermometry, where the Ln31-doped (e.g., Nd31, Er31, or Tm31) nanomaterials act as temperature sensors, especially when they have the thermally coupled levels (TCLs), with energy separation of about 200
2000 cm21 [1,23,25,28
31]. The optical, contactless nanosensors of pressure and temperature can be used in various applications,

Pressure and temperature optical sensors

229

Figure 10.1 Schematic representation of the pressure- and temperature-dependent luminescence properties of Ln21/31-doped materials, which can be used for nanomanometry and nanothermometry.

where the noncontact determination of local pressure/temperature values is necessary, for example, investigation of continuous changes of spectroscopic and structural properties of the materials at high-pressure and temperature conditions, formations of new materials under extreme conditions, phase transitions, investigation of the geological processes and phenomena taking place inside the planets/ stars, thermal bioimaging, photodynamic therapy, and hyperthermia treatment. This is especially important in the case of applications requiring high spatial resolution of the remote measurement, for example, in the micro/submicro-sized systems and in biological systems. Fig. 10.1 shows the pressure- and temperature-dependent luminescence properties of Ln21/31-doped materials, that is, band ratio, spectral shift, intensity, bandwidth and lifetimes, which can be used in nanomanometry and nanothermometry.

10.2

Temperature measurements—general remarks

There are different systems allowing measurements of the temperature impact on the luminescence properties of the studied materials, for example, thermostatic chambers, cryostats, heating baths, various homemade or adapted heating devices, and tube furnaces, where the temperature is calibrated with a traditional

230

Handbook of Nanomaterials in Analytical Chemistry

thermosensor, such as a thermocouple. Owing to the availability reasons and relatively low cost, the last one, that is, tube furnace seems to be one of the most used apparatus for luminescence measurements under elevated temperature conditions. Such systems should provide temperature stability and accuracy of at least 6 1K or better. The solid sample can be fixed, for example, between two pieces of glass/quartz (or in a cuvette in the case of the solution/colloid) in the center of the furnace’s tube. In case of the colloidal NPs measured in the so-called biological range of temperature, that is, B290K
320K, the better option is to use a system similar to the thermostatic heating bath equipped with a stirring system, in order to avoid particles sedimentation and provide their homogeneous distribution during the measurements. The sample is irradiated with, for example, a focused beam of the UV lamp or with laser beam, and then the luminescence signal is focused on the spectrometer slit coupled with a detector (PMT or CCD camera). Noteworthy, in the case of the use of high-energy light source, for example, focused laser beam, it is important to adjust power of the laser (power density) to be low enough to avoid the undesired temperature increase of the sample caused by heating of the material. Such requirement is fulfilled, for example, when no laser-induced thermalization of the levels occurs, that is, the band ratios of the thermalized transitions (in ions such as Nd31, Er31, Tm31) remain unchanged at a constant temperature value. One of the most problematic issues is, or should be, the intensity of the luminescence signal, obviously related to the quantum yield (QY) of the luminophore. This is especially important in the case of the UC NPs, whose QY is usually very low (B1023%
1022%). The QY of about 0.1%
1% is considered to be a high value, obtained usually for the complex core/shell NPs or luminescentplasmonic systems, whose synthesis is not straightforward and rather complicated [32,33]. The UC QY has usually higher values for the NPs synthesized in high boiling solvents, having organically modified surface, compared to the ones obtained via a typical hydrothermal method [32,33]. Moreover, it is worth noting that the elsewhere reported QY values are measured using different power density of the lasers (excitation source). Hence, it is very hard to compare the QY values between different reports, as for the UC materials (requiring multiphoton excitation) their luminescence QY is dependent on the pump power density (W cm22), exhibiting also a nonlinear dependency. It should be emphasized that the low signal-to-noise ratio, which usually even decreases with temperature, leads to larger measuring errors and uncertainties in the temperature determination. If the material has high thermal sensitivity, but low QY (at a moderate pump power density), resulting in a low signal-to-noise ratio, it cannot be considered as a good thermometer for bioapplications, which requires a strong luminescence signal (highly penetrable through the tissues). One should remember that increasing the pump power density will result not only in the enhanced luminescence signal, but also will lead to the heating of the irradiated material and may cause undesired damage of the sample (tissue) studied.

Pressure and temperature optical sensors

10.3

231

Remote, contactless temperature sensing

The optical, noncontact determination of temperature value of the system can be effectively realized utilizing organic fluorophores, metal complexes, quantum and carbon dots, gold nanorods, lanthanide-doped materials, etc., whose luminescence signal is sensitive to temperature alterations [28
31]. However, due to the previously mentioned favorable features of lanthanide-doped NPs, they seem to be the most promising candidates as modern optical, contactless (luminescent) nanosensors of temperature. Determination of the system temperature via luminescence thermometry requires measurements of some spectroscopic properties of the materials, for example, shape of the emission spectra, intensity changes of the emission band or bands, bandwidth, spectral shift, shortening of luminescence rise or decay times (emission lifetimes), which can act as thermometric parameters [28
31]. However, the most common approach in the contactless lanthanide thermometry is based on the fluorescence intensity ratio (FIR) technique, which in the case of the 4f
4f transitions of Ln31-doped systems should be called luminescence intensity ratio (LIR). This method is characterized by a rapid measurement, high accuracy/precision, and high resolution [28
31]. The FIR technique is based on the temperature-dependent changes of the intensity ratio of emission bands, corresponding to the two TCLs of some ions (e.g., Pr31, Nd31, Ho31, Er31, Tm31) having an appropriate energy separation between their thermalized states, usually being in the range of 200 # ΔE # 2000 cm21 [1,23,25,28
31,35]. The smaller energy difference between the electronic states, usually results in a strong overlapping of the two thermally coupled bands, whereas the larger energy separation may lead to the insufficient population of the upper energy level, in the temperature range of interest. Fig. 10.2 presents a typical scheme of the energy levels in the UC Yb31/Er31 system, depicting the energy difference between the TCLs of Er31 (2H11/2 and 4S3/2). When the temperature-populated upper energy level (I2) is situated B200
2000 cm21 above the lower energy level (I1), the thermalization process, which is favored at higher temperature, takes place according to the Boltzmann distribution: LIR 5 FIR 

  I2 2 ΔE 5 Bexp kB T I1

(10.1)

where FIR is the fluorescence intensity ratio (LIR is the luminescence intensity ratio); I2 is the integrated intensity of the higher energy transition; I1 is the integrated intensity of the lower energy transition; ΔE is the energy difference between the centroids of those two transitions (E2 2 E1); kB is the Boltzmann constant; T is the absolute temperature; and B is the constant which depends on the degeneracies of states, total spontaneous emission rates, transitions branching ratio relatively to the ground state and angular frequencies of the transitions [30]. The FIR of such two transitions is known as a thermometric parameter, as it is directly

232

Handbook of Nanomaterials in Analytical Chemistry

Figure 10.2 Scheme presenting the energy-level diagram in the Yb31/Er31-codoped system, indicating the UC energy transfer (Yb31!Er31), and thermalization processes between the thermally coupled levels of Er31 (2H11/2 and 4S3/2).

related to the temperature of the luminescent material and conforms to Boltzmann distribution [28
31]. The ΔE values are usually derived from the emission spectra or by fitting process. Another commonly used parameter in luminescence thermometry is its relative sensitivity, Sr (in %K21), which is defined as [29]: Sr 5 100% 3

1 @FIR ΔE 5 100% 3 FIR @T kB T 2

(10.2)

1 @MP MP @T

(10.3)

or more generally Sr 5 100% 3

where MP represents the measured parameter, for example, band ratio, luminescence lifetime, and spectral shift. The Sr shows how the MP changes per 1K of the absolute temperature. Another thermometric parameter is the absolute sensitivity, Sa [29,30]: Sa 5 100% 3

@MP @T

(10.4)

Pressure and temperature optical sensors

233

However, in order to quantitatively compare the performance of various luminescence thermometers (different materials and dopant ions), only the Sr value should be used, as it is independent of the sample properties and the measuring setup. It is also worth to mention about the temperature resolution, that is, temperature uncertainty, δT, that is, the smallest detectable (by luminescence thermometry) change of temperature, which is defined as: δT 5

1 δMP Sr MP

(10.5)

where δMP denotes the uncertainty of determination of the measured parameter. Depending on the luminescent thermometer material characteristics and detection system used, the δT varies from 1021K to 1023K for different lanthanide-doped materials. More information about the δT and δMP determination can be found in the works of Brites et al. [29,30]. Another factors concerning luminescent thermometers are the repeatability and reproducibility of measurements of the spectroscopic (thermometric) parameters, and the related temperature determination. Besides the obvious mistakes of the operator, imperfection of the measuring setup, unadjusted and uncorrected detection systems, environmental factors, etc., the most critical factors are the sample thermoand photostability. In other words, the material working as a thermometer cannot exhibit any phase transitions in the measured temperature range, as well as it must be resistant to the exposure of the excitation light, without any traces of photooxidation/degradation of the material. Another aspect, which seems to be especially important in the case of small NPs (with high surface-to-volume ratio), is their surface characteristics. If the NPs are hydrophilic, they can absorb water molecules from the air (depending on the humidity of the environment) and then release them, as exhibiting different spectroscopic response when the sample is heated and subsequently cooled down (in temperature range B290K
400K). Alternatively, if the luminescent NPs contain organic molecules on their surface (stabilizers), which in fact is a common practice, such compounds may oxidize and decompose under high-temperature conditions (above B450K), completely changing the spectroscopic characteristics of the sample, and resulting in luminescence deterioration. Hence, it is necessary to perform the so-called yo-yo experiments, that is, the repeatable cycles of increasing and decreasing temperature (heating and cooling the material), in order to check the potential variations and chemical stability of the sample and its surface [30]. As currently most of the thermometric studies based on the Ln31 luminescence use the FIR technique, it should be pointed out that there are also some reports concerning the use of LIR of the non-TCLs, for temperature sensing purposes [25,36]. This is possible because of various temperature-regulated energy transfer processes, phonon-assisted quenching, thermal population of some energy levels in the Ln31-doped systems, etc. One of the examples can be the use of visible and NIR emissions of the UC crystals of NaLuF4 and NaYF4, multidoped with Yb31,

234

Handbook of Nanomaterials in Analytical Chemistry

Figure 10.3 Luminescence intensity ratios and relative sensitivities obtained for different transitions in the NIR range, under excitation at 975 nm for a NaLuF4:Yb31
Er31
Ho31 sample. Source: Adapted from M. Runowski, A. Bartkowiak, M. Majewska, I.R. Martı´n, S. Lis, Upconverting lanthanide doped fluoride NaLuF4:Yb31-Er31-Ho31—optical sensor for multi-range fluorescence intensity ratio (FIR) thermometry in visible and NIR regions, J. Lumin. 201 (2018) 104
109, with permission from Elsevier.

Er31, and Ho31 ions, where the ratio of the emission bands of Ho31 to Er31 was successfully used for temperature sensing (Fig. 10.3), in the first, second, and third biological windows [25,36]. Usually most of the optical thermometers need independent temperature calibration before their use as temperature sensors, so they are so-called secondary thermometers. Whereas the so-called primary thermometers are described by an equation of state, which relates directly the measured effect (e.g., intensity, band ratio, and spectral shift) with the absolute temperature. Such thermometers do not require external temperature calibration, and can be used in different media without additional recalibration procedure [29,30,37].

10.4

Nanothermometry

As this chapter is devoted to Ln31-doped optical pressure/temperature nanosensors, and currently there are hundreds of reports concerning inorganic NPs doped with Ln31 working as NTMs, the organic, metal-organic complexes

Pressure and temperature optical sensors

235

(including MOF - metal
organic framework), as well as other “nonlanthanide” nanomaterials, such as semiconducting quantum dots, carbon dots, and gold nanorods acting as temperature sensors, will not be discussed here in detail. More details on those topics one can find in the works of Jaque et al. and Brites et al. [28
30], as well as Carlos and Palacio [31]. One of the most appealing benefits from the use of nanothermometry is an exceptionally high spatial resolution of this technique (down to several nm). This is due to the use of small NPs acting as optical, noncontact NTMs. Thanks to the relatively low cytotoxicity of Ln31-doped NPs and their small size, comparable or smaller to living organelles/cells, such NTMs can be effectively used in various bioapplications, for example, for thermal sensing, bioimaging, and hyperthermia treatment [28,30,31]. Moreover, they can be used in other applications requiring submicro resolution, for example, in a precise detection of local temperature of the system, under high-pressure conditions, in a diamond anvil cell (DAC) [1]. Using nanothermometry for temperature sensing in biological systems, one should consider the use of NIR excitation light, instead of the typical UV excitation. It is well known that UV light is harmful and may damage the living cells and organic tissues, being simultaneously less penetrable for them (because of light scattering and reabsorption processes), compared to NIR light. Hence, currently the upconverting and other NIR excited Ln31-doped NPs, are commonly used as NTMs [28
31]. Briefly, the UC luminescence is an anti-Stokes emission, resulting from the two- or multiphoton absorption processes. This phenomenon involves the conversion of the lower energy NIR light to higher energy photons, in the visible and/or UV spectral range. Owing to the high absorption cross section of the Yb31 ion, it usually acts as a sensitizer (energy donor), transferring the absorbed excitation energy to the emitting activator ions (energy acceptors, e.g., Ho31, Er31, and Tm31), pumping their excited states via ETU mechanisms [1,2,26,27]. Currently, there is a very high demand for the new contactless sensors, due to the rapid development of various bioapplications utilizing luminescent NPs. The temperature sensing in a biological range (B290K
330K), in the first (650
950 nm), second (1000
1350 nm), and third (1550
1870 nm) biological window is a particularly important issue. There are many studies of the optical temperature sensors working in the first biological window [28
31]. However, there is a limited number of reports concerning optical temperature sensors working in the second and third optical windows [25,36,38,39]. Most of the researchers use the Yb31 excitation (at B980 nm), observing the subsequent emission of the activator ions, for example, Ho31, Er31, and Tm31 [28
31]. Unfortunately water and other liquids present in the biological systems highly absorb in that range, as well. That is why, there is observed increased interest in the Nd31-doped or codoped (Nd31! Yb31! Ho31/Er31/Tm31) systems, where Nd31 ion is excited in a first biological window (at B800 nm), emitting in the first and second biological windows [38,40
43], or transferring the energy to Yb31 and then to other emitting ions [39].

236

Handbook of Nanomaterials in Analytical Chemistry

10.4.1 Single-band intensity and double-band ratio nanothermometers 10.4.1.1 Pr31 Zhou et al. [44] reported the hydrothermal synthesis of β-NaYF4:Pr31 0.8% hexagonal microprisms (800 nm 3 2.5 μm) and the analogs NPs (B24 nm) via a solution-based method. They used FIR technique measuring the intensity ratio of Pr31 emission bands at 525/540 nm (3P1!3H5/3P0!3H5), at λex 5 473 nm. The TCLs 3P1 and 3P0 of Pr31 were separated by ΔE B450 cm21, resulting in a max Sr B5%K21 at 120K (read from the graph). A similar approach was used by Pudovkin et al. [45] who compared the Sr values both for NPs (B20 nm; Sr B2.3% at 110K) and large bulk crystals (Sr B8% at 110K) of LaF3:Pr31 (12% in nano and 1% Pr31 in bulk). The researchers showed that Sr of the NTMs increases when the concentration of Pr31 ions decreases (λex 5 444 nm). In both reports the authors emphasized the significantly lower luminescence intensity of the NPs, compared to their bulk analogs.

10.4.1.2 Nd31 There is a huge number of reports concerning Nd31-activated luminescent thermometers, due to the ladder-like structure of its energy levels, as well as absorption and emission in the first and second biological windows [38
43,46
51]. Moreover, Nd31 may act alike an activator ion, and as a sensitizer usually in the UC systems using λex B800 nm, for example, Nd31! Yb31! Ho31/Er31/Tm31 [39]. One of the first reports concerning Nd31-doped NTMs was the work of Wawrzynczyk et al. [40], who synthesized cubic α-NaYF4:Nd31 10% and 15% NPs (B25 nm) via a thermal decomposition reaction. The authors used FIR technique by measuring the 863/870 nm band ratio (4F3/2!4I9/2 transition) of the TCLs, corresponding to the Stark components (ΔE B60 cm21) of the 4F3/2!4I9/2 transition of Nd31, at λex 5 830 nm. The max Sr was B0.12%K21 at 273K. A similar approach was used by Benayas et al. [41], who used the ratio of different Stark components (ΔE B95 cm21) at 938/945 nm of the same transition (4F3/2!4I9/2), originating from the Y3Al5O12:Nd31 1% NPs (B65 nm), at λex 5 808 nm, resulting in a Sr B0.15%K21 at 293K. The nanomaterial was synthesized by a high-temperature combustion process. The authors successfully used the calibrated NTMs for temperature sensing in microelectronics, opto-fluidic devices, and subtissue ex vivo experiments (using a chicken breast). The analogs approach (FIR of Stark sublevels at 865/885 nm, of the 4F3/2!4I9/2 transition) was used by Carrasco et al. [42], who used LaF3:Nd31 5%
25% NPs (B12 nm), synthesized via a coprecipitation method as NTMs, with Sr B0.26%K21 at 296K. The NPs were used simultaneously as nanoheaters and NTMs (λex 5 808 nm), for hyperthermia treatment of mice tumors formed by subcutaneous inoculation of cancer cells. The directly injected NPs were irradiated with the laser beam, resulting in tumor cells destruction and rapid temperature readout (B323K). Balabhadra et al. [43] shown the use of Gd2O3:Nd31 1%
5% nanorods

Pressure and temperature optical sensors

237

(B13 3 90 nm) as NTMs, synthesized via a simple coprecipitation, at mild temperature and ambient pressure, using λex B580 nm (emission) and 808 nm (lifetimes). The authors used FIR technique measuring the intensity ratio of Nd31 emission bands at 825/890 nm (4F5/2!4I9/2/4F3/2!4I9/2), resulting in a max Sr B1.75%K21 at 288K. The TCLs 4F5/2 and 4F3/2 of Nd31 were separated by ΔE B1100 cm21. Recently, Herna´ndez-Rodrı´guez et al. [38] reported interesting results concerning Nd31-doped nanoperovskites YAlO3:Nd31 1% (B40 nm) synthesized by a sol
gel method, as very effective NTMs working in the first and second biological windows. On the basis of FIR method, the 820/890 (2H9/2,4F5/2!4I9/2/4F3/2!4I9/2) band ratio was correlated with temperature in the range of 293K
611K, using λex B532 nm. Thanks to the presence of TCLs (2H9/2,4F5/2, and 4F3/2) the FIR conformed to Boltzmann distribution, resulting in a Sr B1.83%K21 at 293K (Fig. 10.4).

Figure 10.4 Temperature evolution of the NIR emission bands of the YAP:Nd31 nanoperovskite (A); experimental intensity ratio (R) and relative sensitivity (SREL) of the YAP:Nd31, based on the emission bands 2H9/2,4F5/2 !4I9/2 and 4F3/2 !4I9/2 transitions (B); schematic diagram showing the experimental procedure to determine the penetration depth of YAP:Nd31 NPs (C); subtissue luminescence intensity as a function of the phantom tissue thickness as obtained for the 4F3/2 !4I13/2 emission of YAP:Nd31 (D). Source: Reprinted from M.A. Herna´ndez-Rodrı´guez, A.D. Lozano-Gorrı´n, I.R. Martı´n, U.R. Rodrı´guez-Mendoza, V. Lavı´n, Comparison of the sensitivity as optical temperature sensor of nano-perovskite doped with Nd31 ions in the first and second biological windows, Sens. Actuat. B 255 (2018) 970
976 with permission from Elsevier.

238

Handbook of Nanomaterials in Analytical Chemistry

10.4.1.3 Sm31 Zhao et al. [52] synthesized β-NaYF4:Sm31 1% NPs (B20 nm) in high boiling solvents, and used them as NTMs, working in temperature range of 300K
430K. After laser excitation at 594 nm, and a resonant absorption from the thermally populated ground state, that is, 6H7/2 to the 4G5/2 level of Sm31, the authors observed emission at B560 (4G5/2!6H5/2), 645 (4G5/2!6H9/2), and 700 nm (4G5/2!6H11/2). The intensity of the observed emission spectra increased with temperature. The authors calibrated the temperature-dependent emission intensity (single-band thermometer) for the 4G5/2!6H5/2 transition, determining the max Sr value of 1.1%K21 at 300K. Whereas Drami´canin et al. [53] reported the use of TiO2:Sm31 1% NPs (B10 nm) obtained by a sol
gel method, as NTMs exhibiting a very high Sr value of 10.15%K21 at 339.5K, working in biological temperature range. The authors correlated with temperature the band ratio of the Sm31 emission at 612 nm (4G5/2!6H7/2; decreasing with temperature) to the trap emission of the TiO2 at 438 nm (almost constant with temperature), using λex 5 360 nm.

10.4.1.4 Eu31 Kolesnikov et al. [54] reported the use of Stark TCLs of the 5D0!7F2 transition of Eu31, in YVO4:Eu31 6% NPs (B60 nm), synthesized via a modified Pechini method [55], for temperature sensing purposes. The FIR of the 614/618 nm (ΔE B61 cm21) Stark components of the 5D0!7F2 transition increased with temperature, ranging from 293K to 333K, and the determined Sr was B0.1%K21 at 293K, using λex 5 300 nm. Huang et al. [56] reported the use of NTMs based on the composite core/shell NPs (B50
100 nm), Zn2SiO4:Mn21 10%@Gd2O3:Eu31 3%, prepared by hydrothermal, coprecipitation, and postsynthesis calcination methods. The authors used correlated band ratio of the Mn21 (B520 nm; 4T1!6A1) and Eu31 (B610 nm; 5D0!7FJ) emission with temperature (303K
623K), using λex 5 260 nm. The determined max Sr was B3.05%K21 at 303K.

10.4.1.5 Gd31 Currently, there are no reports about Gd31-based nanothermometry, and there is only one report of the use of Gd31 embedded in a bulk, inorganic matrix, working as optical thermometer, done by Zheng et al. [57], hence it will be discussed here as a representative example. The authors synthesized via hydrothermal method β-NaLuF4:Yb31 20%, Tm31 0.7%, Gd31 20% microprisms (1.2 3 3 μm), exhibiting UC luminescence by Yb31 (sensitizer) excitation (λex 5 980 nm), and a subsequent energy transfer to Tm31 (energy mediator), and finally to the emitting Gd31 (activator ion). The authors used FIR method and correlated the temperatureinduced increase of the 307/312 (6P5/2!8S7/2/6P7/2!8S7/2; ΔE 5 464 cm21) and 277/280 nm (6I9/2!8S7/2/6I7/2!8S7/2; ΔE 5 284 cm21) band ratios, corresponding to the TCLs 6P5/2, 6P7/2, and 6I9/2, 6I7/2 of Gd31 ion, respectively. The measurements were performed in temperature range from 298K to 523K, and the max Sr

Pressure and temperature optical sensors

239

values (determined from the graph) were B0.59%K21 at 333K (307/312 nm) and B0.47%K21 at 298K (277/280 nm).

10.4.1.6 Dy31 One of the first reports concerning Dy31-activated temperature nanosensors is the work of Cao et al. [58], who used BaYF5:Dy31 2% NPs (B20 nm) as NTMs operating at high temperature range (300K
800K), exhibiting high Sr value of about 2%, around 650K. The nanomaterial was obtained by hydrothermal method, and the emission was observed at λex 5 355 nm. The authors utilized FIR technique, measuring the temperature-dependent changes of the 455/478 nm (4I15/2!6H15/2/4F9/2!6H15/2) band ratio, corresponding to the TCLs 4I15/2 and 4F9/2 of Dy31, with energy separation, ΔE B1000 cm21. A similar approach based on ´ the same Dy31 TCLs, and FIR technique was used by Culubrk et al. [59], who syn31 thesized Gd2Ti2O7:Dy 1% NPs (B10
30 nm) via a sol
gel Pechini method [55]. The prepared NTMs were investigated in temperature range of 293K
443K, and exhibited max Sr value of 1.68%K21 at 293K, at λex 5 350 nm.

10.4.1.7 Ho31 Savchuk et al. [60] synthesized KLu(WO4)2:Yb31 10%, Ho31 1% NPs (B40
60 nm) by a modified Pechini sol
gel method [55], and used them as UC (λex 5 980 nm) NTMs, working in a temperature range from 297K to 673K. The Authors used multiple techniques for temperature sensing, that is, FIR of two Stark TCLs (650/660 nm; 5F5!5I8; Sr 5 0.385%K21 at 297K), band ratio of the TCLs red and green emission bands (540/650 nm; 5F5!5I8/2S2,5F4!5I8; Sr 5 0.54%K21 at 297
673K), lifetime measurements (540 nm, 5F5!5I8, αT 5 0.23%K21; 650 nm, 2S2,5F4!5I8, αT 5 0.19%K21), and by the color change of the emitted light. Li et al. [61] used β-NaYF4:Yb31 20%, Ho31 2% NPs (B300
400 nm), synthesized via solvothermal method as NTMs working in temperature range from 300 to 500K. The authors protected the obtained UC (λex 5 980 nm) NTMs by the use of a micro-sized SiO2 capillary tube, filled with the NPs. They used FIR technique for temperature sensing, using the band ratio of the TCLs of Ho31 (i.e., 545/650 nm; 5F5!5I8/2S2,5F4!5I8 and 750/650 nm; 5 F5!5I8/2S2,5F4!5I8), resulting in the Sr values of about 0.9 and 1.53%K21 at 300K, respectively.

10.4.1.8 Er31 The first report directly related to nanothermometry based on the Er31-doped UC NPs, is the paper of Alencar et al. [62], who synthesized the BaTiO3:Er31 0.5% and 2% NPs (B25
60 nm) via a sol
gel method. The authors used FIR method and correlated the temperature-driven change of the 526/547 nm band ratio, corresponding to the UC luminescence of Er31 TCLs (2H11/2!4I15/2/4S3/2!4I15/2), using λex 5 980 nm. They observed the increase of the band ratio with increasing temperature value, measured in the range from 322 to 466K, resulting in a thermal

240

Handbook of Nanomaterials in Analytical Chemistry

sensitivity of the NTMs of about # 0.52%K21. Singh et al. [63] investigated the UC (λex 5 976 nm) Gd2O3:Yb31 (0%
0.6%), Er31 (0%
3.5%) NPs (#50 nm), obtained by combustion method, in temperature range from 300K to 900K. The authors also used FIR method, based on the TCLs of Er31 (2H11/2!4I15/2/4S3/2!4I15/2) with ΔE B545 cm21, correlating the increase of the 523/548 nm band ratio, related to UC luminescence of Er31. The max Sr was about 0.85%K21 at 300K (determined from the graph). Sedlmeier et al. [64] reported the synthesis of UC hexagonal β-NaYF4:Yb31 20%, Er31 2% NPs, and the corresponding core/shell NaYF4:Yb31, Er31/NaYF4 NPs, and their use as NTMs working in a biological range of temperature, that is, 293K
333K. The NTMs were synthesized via a coprecipitation and subsequent thermal posttreatment method (B100 nm), as well as by thermal decomposition of organic solvents (B30 nm). The authors observed temperature-induced decrease of the Er31 UC emission bands at 656 (4F9/ 4 4 4 2! I15/2) and 541 nm ( S3/2! I15/2), whereas the intensity of the band at 523 nm 2 4 ( H11/2! I15/2) was almost constant with increasing temperature (λex 5 980 nm). They used the 656/541 and 541/523 band ratios for temperature sensing, and determined the temperature resolution of the obtained NTMs to be ,0.5K, in the measured temperature range. Balabhadra et al. [37] reported the use of UC SrF2:Yb31 20%, Er31 2% NPs (B10, 30, and 40 nm) as “primary,” self-referring NTMs, synthesized via hydrothermal method. The authors used FIR method, measuring the temperature dependence of Er31 UC emission (λex 5 980 nm), that is, the band ratio 525/545 nm (2H11/2!4I15/2/4S3/2!4I15/2), due to the presence of TCLs 2H11/2 and 4 S3/2 of Er31, with energy difference ΔE B750 cm21. The measurements were performed in the temperature range from 298K to 383K, and the determined Sr was about 1.20%K21 around 300K. Geitenbeek et al. [65] reported the preparation of UC core/shell β-NaYF4:Yb31 18%, Er31 2%/SiO2 NPs (B30 nm), obtained by thermal decomposition of high boiling solvents, and the subsequent synthesis in microemulsion, in order to form the silica shell (Fig. 10.5).

Figure 10.5 TEM images of the synthesized NaYF4 (A) and NaYF4@SiO2 NPs (B). Source: Reprinted from R.G. Geitenbeek, P.T. Prins, W. Albrecht, A. Van Blaaderen, B.M. Weckhuysen, A. Meijerink, NaYF4:Er31,Yb31/SiO2 core/shell upconverting nanocrystals for luminescence thermometry up to 900K, J. Phys. Chem. C 121 (2017) 3503
3510. Published by American Chemical Society.

Pressure and temperature optical sensors

241

Figure 10.6 UC emission spectra of Er31-doped NaYF4@SiO2 NPs (λex 5 980 nm), recorded in temperature range from 300K to 900K. Source: Reprinted from R.G. Geitenbeek, P.T. Prins, W. Albrecht, A. Van Blaaderen, B.M. Weckhuysen, A. Meijerink, NaYF4:Er31,Yb31/SiO2 core/shell upconverting nanocrystals for luminescence thermometry up to 900K, J. Phys. Chem. C 121 (2017) 3503
3510. Published by American Chemical Society.

Thanks to the presence of silica shell, the obtained NPs were resistant to high-temperature treatment (did not decompose), as they were used as hightemperature UC NTMs, working in the range from 300K to 900K. For temperature sensing, the authors used a standard FIR method for Er31, that is, the temperaturedependent band ratio 520/545 nm (λex 5 980 nm), related to the TCLs 2H11/2 and 4 S3/2 of Er31, separated by ΔE B716 cm21. The determined max Sr was 1.02% K21 at 300K. Fig. 10.6 shows a set of UC emission spectra of Er31 (in NaYF4: Er31,Yb31/SiO2 NPs), recorded in temperature range from 300K to 900K, clearly presenting the temperature-induced increase of the Er31-thermalized band at B525 nm (2H11/2). Suo et al. [66] synthesized La2O3, Gd2O3, and Y2O3 UC NPs (B140 nm) doped with Yb31 3% and Er31 2%, via a coprecipitation and subsequent thermal posttreatment method. The authors used the same FIR technique for temperature sensing in the range from 280K to 490K, using λex 5 980 nm. Depending on host matrices used, the calculated ΔE B760
780 cm21 and the max Sr value were similar for all samples, that is, B1.1%K21 at 280K (determined from the graph). The authors successfully used the UC La2O3:Yb31, Er31 NPs (which exhibited an order of magnitude higher UC luminescence intensity, compared to other samples) for ex vivo temperature sensing (subtissue thermometry), injecting 0.1 mL aqueous solution of the sample (1 mg mL21) to B1 mm depth, into a fresh chicken breast. For comparison, the results from thermal camera and FIR technique resulted in almost the same temperature values, in the range from 300K to 330K.

10.4.1.9 Tm31 One of the first reports concerning Tm31-activated NTMs, is the work of Dong et al. [67], where the authors synthesized CaF2:Yb31, Tm31 NPs (B11 nm) via a

242

Handbook of Nanomaterials in Analytical Chemistry

hydrothermal method, using citrate ions as capping agents. The as-prepared NPs exhibited bright, temperature-dependent UC luminescence (λex 5 920 nm), thanks to the presence of thermally coupled sub-Stark energy levels belonging to the 3 H4!3H6 transition in Tm31 ion. The NPs were successfully used as a temperature sensor for cellular imaging in a biological range of temperature (298K
323K), using the FIR technique, that is, change of the 790/800 nm band ratio. The other work reported by Zhou et al. [68] presents the UC (λex 5 980 nm) core/shell β-NaYF4:Yb31, Tm31/NaYF4:Pr31 elongated NPs (B27
39 nm) synthesized in high boiling solvents. The NPs were used as NTMs (302K
510K) based on the temperature-induced intensity increase of the thermalized 3F2,3!3H6 transition (at B700 nm) in Tm31, hence working as single-transition NTM. Their Sr value reached 1.53%K21 at 417K. Savchuk et al. [69] reported the use of GdVO4:Yb31, Tm31@SiO2 core/shell NPs (B35 nm) as UC (λex 5 980 nm) NTMs (300K
673K), with Sr 5 1.54%K21 at 673K. The authors correlated the 700/ 475 nm (3F2,3!3H6/1G4!3H6) band ratio with temperature, with temporal resolution ,16 ms, showing the possibility of monitoring the heating process of a platinum wire, and visualizing the temperature distribution on a heated platinum plate coated with those NPs (Fig. 10.7).

Figure 10.7 Temperature evolution (301K
673K) of UC emission spectra for GdVO4:Yb31, Tm31@SiO2 NPs, doped with 1% (A) and 0.2% of Tm31 (B); scheme of the setup for the real-time visualization of temperature distribution (C); thermal images corresponding to the Pt plate showing the temperature gradient generated, and emission generated by the layer of NPs coating the Pt plate during the heating process (D). Source: Reprinted from O.A. Savchuk, J.J. Carvajal, C. Cascales, J. Massons, M. Aguilo´, F. Dı´az, Thermochromic upconversion nanoparticles for visual temperature sensors with high thermal, spatial and temporal resolution, J. Mater. Chem. C 4 (2016) 6602
6613 with permission from The Royal Society of Chemistry.

Pressure and temperature optical sensors

243

Pereira et al. [70] reported the use of sub-Stark TCLs of the 1G4!3H6 transition of Tm31 in NaNbO3:Yb31, Tm31 UC NPs (B70 nm) at λex 5 940
975 nm. The FIR of the 480/486 nm (1G4!3H6 transition) increased with temperature, ranging from 293K to 353K. The Sr value was B0.1%K21 (determined from the graph), and it was almost constant over the measured temperature range. Du et al. [71] used UC (λex 5 980 nm) NaYbF4:Tm31 NPs (B29 nm), synthesized via hydrothermal route as NTMs, working in a first biological window. The authors used FIR technique, correlating the 700/800 nm (3F2,3!3H6/3H4!3H6) band ratio of the TCLs with temperature, in the range of 298K
778K. On basis of the same FIR approach (Tm31 700/800 nm) and using UC (λex 5 975 nm) LaPO4:20% Yb31 2 0.5% Tm31 (B70
150 nm) NPs, Runowski et al. [1] determined the temperature (473K) of the heated micro-sized system (,150 μm pressure chamber) compressed under high-pressure conditions (B1.5 and B5 GPa). Such temperature sensing under pressure was possible as both Tm31 bands (3F2,3!3H6/3H4!3H6) were thermally coupled (ΔE B1790 cm21), and the pressure affected them in a similar way, with no influence on their band ratio.

10.4.1.10 Tb31 and Yb31 In general, Tb31 and Yb31 ions are not suitable for luminescence thermometry using the FIR technique, based on the TCLs. This is because the lowest excited state of Tb31 (5D4 level) is isolated by B6000 cm21 from its second, upper lying excited state (5D3). Although Yb31 (often used as a sensitizer in UC nanothermometry) has a simple electronic configuration, that is, one ground 2F7/2 and one excited 2F5/2 state, separated by B10,000 cm21. However, there are some examples of the use of temperature-dependent luminescence of those ions (or temperatureindependent emission of Tb31, acting as a self-reference for the other emitting species), in combination with other emitting Ln31 ions, which will be discussed in the next section concerning multicenter NTMs [72,73].

10.4.2 Dual and multicenter nanothermometers Currently an increasing amount of reports concerning NTMs based on the dual or multicenter emission from different Ln31 ions is observed, including the use of thermalized and nonthermalized emitting levels in simple NPs, core/shell and composite nanomaterials [30,36,39,48,72,73]. Hence, only a few representative examples will be discussed here in more detail, as, for example, the work of Ximendes et al. [72], who designed the UC core/shell LaF3:Yb31 10%, Er31 2%/LaF3:Yb31 10%, Tm31 10% NPs (B32 nm), prepared by coprecipitation and subsequent thermal posttreatment method, and used them as infrared NTMs for in vivo temperature sensing (293K
323K). The NTMs worked in the first and second biological windows, using the following band ratios: Yb31/Tm31 1000/1230 nm (2F7/2!2F5/2/3H5!3H6), Yb31/Er31 1000/1550 nm (2F7/2!2F5/2/4I13/2!4I15/2), and Tm31/Er31 3 3 4 4 1230/1550 nm ( H5! H6/ I13/2! I15/2). The obtained NTMs exhibited superior thermal sensitivities, as their max Sr values for the 1000/1230 and 1000/1550 nm band

244

Handbook of Nanomaterials in Analytical Chemistry

ratios were 3.9 and 5.0%K21, respectively at 293K (λex 5 690 nm). The exceptionally high Sr values, were related to the spatial separation of the emitting Tm31 and Er31 ions, in the designed core/shell type structure. The authors used the obtained NTMs as thermal sensors in the performed in vivo experiments, by a subcutaneous injection of the colloidal NPs to mouse, and 2D imaging of the temperature changes induced by a laser irradiation. Zheng et al. [73] reported the use of UC (λex 5 980 nm) hexagonal NaGdF4:Yb31 49%, Tb31 1%/NaGdF4:Tb31 15%, Eu31 1.5% core/shell NPs (B32 nm), synthesized by a thermal decomposition method, as NTMs working in a temperature range from 125K to 300K. The authors correlated the temperatureinduced change of the band ratio Tb31/Eu31 545/615 nm (5D4!7F5/5D0!7F2), resulting in Sr of about 1.2%K21 in the whole temperature range. Zhou et al. [48] used Y2O3:Eu31 5%, Nd31 1% NPs (B50
100 nm) obtained by combustion method, working as NTMs in temperature range from 300K to 510K. The authors correlated with temperature the increase of the band ratio Nd31/Eu31 820/700 nm (4F5/2!4I9/2/5D0!7F4), at λex 5 580 nm, and determined the max Sr to 2.58%K21 at 380K. Kamimura et al. [36] reported the use of β-NaYF4:Yb31 1%, Ho31 1%, Er31 1% NPs (B52 nm) obtained by thermal decomposition method, as UC (λex 5 980 nm) NTMs working in the second and third optical windows, in the biological range of temperature 298K
323K. The authors correlated with temperature, the linear change of the band ratio Ho31/Er31 1150/1550 nm (5I6!5I8/4I13/2!4I15/2). To improve the biocompatibility and stability of the colloidal NPs in water, their surface was modified with polyethylene glycol (PEG). The Sr for the PEGylated NPs was about 0.7%K21 (read from the graph). The obtained NTMs were successfully used for temperature sensing through the 2-mm chicken breast, and for NIR luminescence bioimaging, after injecting into the live mouse (Fig. 10.8). Recently, Marciniak et al. [74
80] reported several new approaches for temperature sensing using luminescent multidoped NTMs based on various Ln31 and d-block transition metal ions (Ti31/41, Mn31/41, Ga31, Cr31, V31/51). The authors used different techniques, such as FIR, lifetime, band-shape, crystal-field modulation for temperature sensing purposes, resulting in the high Sr values of the NTMs studied, up to B2
4%K21. They investigated the influence of concentration of Ln31 and d-block ions, on the thermal sensitivity of the obtained NTMs. Fig. 10.9 presents thermal evolution of the exemplary emission spectra of the Cr31/ Yb31 codoped NPs, and the determined FIR (LIR) and Sr values.

10.4.3 Nanothermometers based on the band shift Spectral shift of the emission line of Ln31 is rarely used for temperature sensing due to its relatively low thermal sensitivity (B1022
1023 nmK21) in comparison to other methods [81
83]. The temperature-induced changes of energy of the 4f
4f transitions, and the corresponding shifts of the emission bands originate from two contributions, namely from the static contribution ΔEst(T) related to the changes in the geometry of the site occupied by the lanthanide ion in the host matrix (caused by the thermal expansion of the crystal lattice), as well as from the vibrational contribution ΔEvib(T) caused by the altered electron 2 phonon

Pressure and temperature optical sensors

245

Figure 10.8 Schematic illustration of ratiometric luminescence nanothermometry based on the NIR-II and NIR-III emission bands of NaYF4:Yb31, Ho31, Er31 NPs (A); energy-level diagram (B); temperature dependence of the UC NIR emission spectra of the PEGylated NPs (C); temperature dependence of the intensity ratio between the IHo/IEr emission bands (D). Source: Reprinted from M. Kamimura, T. Matsumoto, S. Suyari, M. Umezawa, K. Soga, Ratiometric near-infrared fluorescence nanothermometry in the OTN-NIR (NIR II/III) biological window based on rare-earth doped β-NaYF4 nanoparticles, J. Mater. Chem. B 5 (2017) 1917
1925 with permission from The Royal Society of Chemistry.

interactions [1]. One of the first observations of the temperature-induced emission line shifts have been done by Kusama et al. [81], who observed the blue-shift of the Eu31 luminescence, in Y2O2S:Eu31 (B0.033 cm21K21). Rocha et al. [83] obtained the colloidal core/shell LaF3:Nd31 15%/LaF3 NPs, by a coprecipitation method, in the presence of citrate ions, and utilized them as NTMs. The authors used the redshift (0.007 nmK21; 0.14 cm21K21) of the Nd31 863 nm emission line (Stark component of the 4F3/2!4I9/2 transition) for temperature sensing. They applied that NTM for temperature sensing of the phantom subtissue, using gold nanorods as nanoheaters, showing their possible application in hyperthermia purposes. Runowski et al. [1] observed the temperature-induced blue-shift (B0.005
0.007 nmK21; B0.12 cm21K21) of the Tm31 emission lines, in the UC (λex 5 975 nm) phosphate NPs, that is, LaPO4 (B70
150 nm) and YPO4 (B20
50 nm), both doped with 20% Yb31 2 0.5% Tm31, measured in the temperature range from 293K to 773K.

246

Handbook of Nanomaterials in Analytical Chemistry

Figure 10.9 Thermal evolution of LiLaP4O12:Cr31, Yb31 NPs emission (A); integrated emission intensity of Cr31 and Yb31, at 650 and 920 nm excitation (B); comparison of normalized LIR for different NPs composition (C); sensitivity of the luminescent thermometer, at 650 and 920 nm excitation as a function of temperature (D). Source: Reprinted from L. Marciniak, A. Bednarkiewicz, Nanocrystalline NIR-to-NIR luminescent thermometer based on Cr31,Yb31 emission, Sens. Actuat. B Chem. 243 (2017) 388
393 with permission from Elsevier.

10.4.4 Nanothermometers based on the bandwidth The temperature-induced broadening of the emission lines is caused by the same factors as the ones mentioned above for the band shift, that is, lattice thermal expansion and electron
phonon interactions. One of the first reports concerning correlation of the temperature (10K
670K) with emission bandwidth (FWHM full width at half maximum) in Ln31-doped NPs has been done by Peng et al. [84], who observed the temperature-induced broadening of the Eu31 emission line at 611 nm (5D0!7F2 transition) in Y2O3:Eu31 1% NPs. Herna´ndez-Rodrı´guez et al. [38] correlated the temperature-induced broadening of the Nd31 4F3/2!4I13/2 band around 1350 nm (in a second biological window) with temperature, that is, increase of the FWHM of the emission band of the previously discussed nanoperovskites YAlO3:Nd31 1% (B40 nm). The determined Sr for this method was very high, that is, B3.3%K21 at 293K. Using the prepared nanosensor, they successfully applied it for temperature sensing of a phantom tissue, that is, the liquid known as intralipid, using λex B895 nm. The authors claimed that the use of their nanoperovskite NTM allows to reach (in vitro) the penetration depths into human skin tissues approximately up to 5.5 mm.

Pressure and temperature optical sensors

247

10.4.5 Lifetime nanothermometers One of the first reports concerning correlation of the temperature (10K
300K) with luminescence lifetime of Ln31-doped NPs has been done by Peng et al. [84], who observed the temperature-induced shortening of the Eu31 emission lifetime for 5 D0!7F2 transition, at 611 nm (λex B355 nm) in Y2O3:Eu31 1% NPs. The shortening of lifetime was explained by an increased temperature-induced quenching of luminescence, that is, enhanced multiphonon relaxation processes. Nikoli´c et al. [85] reported the temperature dependence of the emission lifetime (τ) related to the Eu31 5 D0!7F2 transition (613 nm), in the TiO2:Eu31 3% NPs (B10
20 nm), in a temperature range of 307K
533K. The τ value decreased from B370 to B20 μs in the temperature range studied, and the determined max Sr value was about 2.43%K21 at 533K. Savchuk et al. [86] used the UC NaYF4:Yb31, Er31, and NaY2F5O:Yb31, Er31 NPs (B300 nm) as lifetime-based NTMs, in a biological range of temperature (298K
333K). The authors determined the thermal sensitivity of the NTMs by calculating the lifetime thermal coefficients, that is, αT (defined as the slope of the normalized lifetime vs temperature linear curve), which were equal to 0.54%K21 and 1.5% K21 for the NaYF4:Yb31, Er31 and NaY2F5O:Yb31, Er31 NPs, respectively. They also demonstrated subtissue thermal sensing in ex vivo experiments, measuring the laser-induced tissue heating by lifetime thermometry, via the subtissue injection of the NTMs, using λex 5 980 nm and λem 5 545 nm. Siaı¨ et al. [87] used the UC La2O3:Yb31 5%, Er31 2%, Tm31 2% NPs (B40 nm) as NTMs (298K
333K), based on the lifetime thermal sensitivity (αT 5 0.67%K21) of the Tm31 emission band around 475 nm, corresponding to the 1G4!3H6 transition. The authors performed the ex vivo experiments on biological tissue, demonstrating that subtissue measurements of the NTMs UC lifetime are possible up to a thickness of 1 mm (Fig. 10.10).

10.4.6 Nanoheaters It is worth noting that the Ln31-doped NPs may act both as NTMs and as nanoheaters [42,46,49
51,88], due to the conversion of light to heat. This is due to the nonradiative processes, leading to the generation of phonon modes in the crystal nanostructure, where the thermal energy dissipates, and the heat is transferred to the surrounding medium. Especially the NPs doped with Nd31 or Yb31 ions are prone to work as nanoheaters, due to their large absorption cross sections in the NIR range, that is, at B800
900 and B900
1000 nm, respectively. That is why, by excitation with a commonly available diode-pumped solid-state continuous wave (CW) 808 nm (Nd31) or 980 nm (Yb31) lasers, it is possible to monitor the temperature using FIR method, and heat the sample/tissue. Applying such luminescent NPs for the subtissue temperature sensing and hyperthermia treatment (temperature-induced damage of the tumor cells), for example, by subcutaneous injection of their colloid, it is possible to simultaneously monitor the temperature value and kill the cells/tissue of interest. Table 10.1 presents a comparison of some representative examples of different Ln31-doped nano-sized, bulk, organic, and other nonlanthanide host materials, exhibiting high relative thermal sensitivity values.

Figure 10.10 Calculated normalized lifetimes as a function of the temperature for the 1G4 level of the La2O3:Tm, Yb (c1) and La2O3:Tm, Yb, Er NPs (c2), where heating and cooling cycles are represented in red (light grey) and blue (dark grey), respectively (A); schematic diagram showing the experimental setup used to measure lifetime luminescence thermometry using La2O3:Tm, Yb, Er NPs (B); subtissue temperature increment measured through lifetime variation of the La2O3:Tm, Yb, Er NPs emission (at 480 nm) as a function of heating laser power, with the sample placed below the biological tissue, of 0.15-mm thickness (C). Source: Reprinted from A. Siaı¨, P. Haro-Gonza´lez, K. Horchani-Naifer, M. Fe´rid, La2O3: Tm, Yb, Er upconverting nano-oxides for sub-tissue lifetime thermal sensing, Sens. Actuat. B Chem. 234 (2016) 541
548 with permission from Elsevier.

Table 10.1 Relative thermal sensitivities (Sr MAX at given T value) of different Ln31-doped nano-sized, bulk, organic, and other nonlanthanide materials; spectral range of the transitions used and the temperature ranges studied. Host

Dopant ions

Sr MAX (%K21)

T (K)

T-range (K)

Transitions

λ (nm)

Ref.

120 110 273 293 296 288 293 293 303
353

120
300 80
320 273
423 283
343 296
345 288
323 293
611 293
611 303
353

3

P1!3H5/3P0!3H5 P1!3H5/3P0!3H5 4 F3/2!4I9/2 (Stark) 4 F3/2!4I9/2 (Stark) 4 F3/2!4I9/2 (Stark) 2 H9/2,4F5/2!4I9/2/4F3/2!4I9/2 2 H9/2,4F5/2!4I9/2/4F3/2!4I9/2 4 F3/2!4I13/2 (bandwidth) 4 F3/2!4I9/2 (Stark) (band shift)

525/540 525/540 863/870 938/945 865/885 825/890 820/890 1350 863

[44] [45] [40] [41] [42] [43] [38] [38] [83]

300 340 293 303

300
430 297
383 293
333 303
623

4

G5/2!6H5/2 G5/2!6H7/2/TiO2 trap emission 5 D0!7F2 (Stark) 4 T1!6A1 (Mn21)/ 5D0!7FJ (Eu31)

560 612/438 614/618 520/610

[52] [53] [54] [56]

533 650 293 297 297
673

307
533 300
800 293
443 297
673

613 455/478 456/483 650/660 540/650 540 650

[85] [58] [59] [60]

300

300
500

D0!7F2 (lifetime) I15/2!6H15/2/4F9/2!6H15/2 4 I15/2!6H15/2/4F9/2!6H15/2 5 F5!5I8 (Stark) 5 F5!5I8/ 2 S2,5F4!5I8 5 F5!5I8 lifetime 2 S2,5F4!5I8 lifetime 5 F5!5I8/2S2,5F4!5I8 5 F5!5I8/2S2,5F4!5I8

545/650 750/650

[61]

300

12
300

541/551

[89]

Nano-sized Ln31-doped inorganic materials β-NaYF4 LaF3 α-NaYF4 Y3Al5O12 LaF3 Gd2O3 nanorods YAlO3 perovskite YAlO3 perovskite LaF3:Nd /LaF3 core/ shell β-NaYF4 TiO2 YVO4 Zn2SiO4: Mn21@Gd2O3:Eu31 TiO2 BaYF5 Gd2Ti2O7 KLu(WO4)2

Pr31 Pr31 Nd31 Nd31 Nd31 Nd31 Nd31 Nd31 Nd31 Sm31 Sm31 Eu31 Eu31 Eu31 Dy31 Dy31 Yb31, Ho31

B5 B2.3 0.12 0.15 0.26 1.75 1.83 3.3 B0.14 cm21K21 1.1 10.15 0.1 3.05 2.43 B2 1.68 0.385 0.54 0.23 0.19

β-NaYF4

YVO4

Yb31, Ho31

Yb31, Ho31

0.9 1.53 1.35

3

4

5 4

5

F4!5S2 (rise time)

(Continued)

Table 10.1 (Continued) Host

Dopant ions

Sr MAX (%K21)

T (K)

T-range (K)

Transitions

λ (nm)

Ref.

BaTiO3 Gd2O3 SrF2 β-NaYF4/SiO2 core/ shell La2O3, Gd2O3, Y2O3 β-NaYF4:Yb31 Tm31/ NaYF4: Pr31 core/ shell GdVO4@SiO2 core/ shell NaNbO3 LaPO4 YPO4

Er31 Yb31, Er31 Yb31, Er31 Yb31, Er31

0.52 B0.85 1.20 1.02

322 300 298 300

322
466 300
900 298
383 300
900

2

H11/2!4I15/2/4S3/2!4I15/2 H11/2!4I15/2/4S3/2!4I15/2 2 H11/2!4I15/2/4S3/2!4I15/2 2 H11/2!4I15/2/4S3/2!4I15/2

526/547 523/548 525/545 520/545

[62] [63] [37] [65]

Yb31, Er31 Yb31, Tm31

B1.1 1.53

280 417

280
490 302
510

2 3

H11/2!4I15/2/4S3/2!4I15/2 F2,3!3H6

525/550 700

[66] [68]

Yb31, Tm31

1.54

673

300
673

3

F2,3!3H6/1G4!3H6

700/475

[69]

293 293

293
353 293
773

1

G4!3H6 (Stark) F2,3!3H6/3H4!3H6

480/486 700/800

[70] [1]

293
773

293
773

1

475,645,700, 800

[1]

1000/ 1230 1000/ 1550 545/615

[72]

[48] [80] [36]

[87]

LaPO4, YPO4

Yb31, Tm31 Yb31, Tm31

Yb31, Tm31

LaF3:Yb,Er/LaF3:Yb, Tm core/shell

Yb31, Er31, Tm31

NaGdF4:Yb, Tb/Tb,Eu core/shell Y2 O3 Gd3Ga5O12 β-NaYF4

Yb31, Tb31, Eu31 31 Eu , Nd31 Cr31, Nd31 Yb31, Ho31, Er31 Yb31, Nd31, Er31, Tm31 Yb31, Er31, Tm31

SrF2:Yb,Tm/Y/Yb,Er, Nd/Nd core/shell La2O3

B0.1 3.00 2.34 B0.12 cm21K21

2

3

G4!3H6,1G4!3F4 F2,3!3H6,3H4!3H6 (band shift) (Yb31) 2F7/2!2F5/2/(Tm31) 3H5!3H6 (Yb31) 2F7/2!2F5/2/(Er31) 4I13/2!4I15/2 3

293

293
323

B1.2

300

125
300

(Tb31) 5D4!7F5/(Eu31) 5D0!7F2

2.58 1.9 B0.7

380 123 323

300
510 123
573 298
323

(Nd31) 4F5/2!4I9/2/(Eu31) 5D0!7F4 (Cr31) 4T2!4A2/(Nd31) 4F3/2!4I9/2 (Ho31) 5I6!5I8/(Er31) 4I13/2!4I15/2

1.62

333

293
333

(Yb31) 2F5/2!2F7/2/(Nd31) 4F3/2!4I11/2

820/700 750/880 1150/ 1550 980/1060

298
333

298
333

(Tm31) 1G4!3H6 (lifetime)

475

3.9 5.0

B0.67

[73]

[39]

Bulk, organic, and other nonlanthanide materials Y2O2S β-NaLuF4

Eu31 Yb31, Tm31 Gd31

NaLuF4 CaWO4 Y2O3

Yb31, Ho31 Yb31, Ho31 Yb31, Ho31

SrSnO3 Fluorotellu-rite glass Tellurite glass GdOF/SiO2 yolk/shell La2CaZnO5 La2CaZnO5 β-NaLuF4

Y2O3

Er31 Er31 Yb31, Er31 Nd31,Yb31, Er31 Yb31, Er31 Yb31, Er31, Ho31 Yb31, Er31, Ho31

B0.033 cm21K21

257
345 333 298

257
345 298
523

5

D0!7F0 (band shift) (Gd31) 6P5/2!8S7/2/(Gd31) 6P7/2!8S7/2 (Gd31) 6I9/2!8S7/2/(Gd31) 6I7/2!8S7/2

583 307/312 277/280

[81] [57]

390 923 85 84 90

390
780 303
923 10 2 300

5

F1,5G6!5I8/5F2,3,3K8!5I8 F1,5G6!5I8/5F2,3,3K8!5I8 5 F4, 5S2!5I8/5F4, 5S2!5I7

444/482 460/487 536/772 536/764 536/758

[90] [91] [92]

294 293 298 260

294
372 293
550 298
473 260/490

2

H11/2!4I15/2/4S3/2!4I15/2 H11/2!4I15/2/4S3/2!4I15/2 2 H11/2!4I15/2/4S3/2!4I15/2 (Er31) 2H11/2!4I15/2/(Er31) 4S3/2!4I15/2

528/549 525/550 525/548 534/543

[93] [35] [94] [51]

0.71 1.52

300 300

300
573 300
573

2

522/548 522/548

[95] [95]

0.74 0.34

298 503

298
503 298
503

2

527/547 659/547

[25]

1.73 0.42 0.21

293 293 430

293
568 293
568 293
568

270 178 290

10 2 300

343

274 2 343

323

273 2 323

B0.59 B0.47 1.60 0.50 9.7 6.5 4.6 0.97 1.28 0.53 1.60

Yb31, Tm31

Eu31-EDTA complex

Eu31

Eu31:P(VDC-co-AN)/ BBS

Eu31

7.8 6.7 6.4 B8 7.2

5

2

2

H11/2!4I15/2/4S3/2!4I15/2 H11/2!4I15/2/4S3/2!4I15/2

H11/2!4I15/2/4S3/2!4I15/2 (Er31) 4F9/2!4I15/2, (Ho31) 5S/2,5F4!5I7/ (Er31) 4S3/2!4I15/2, (Ho31) 5S/2,5F4!5I8 (Ho31) 5I5!5I8/(Er31) 4I9/2!4I15/2 (Ho31) 5I5!5I8/(Er31) 4I13/2!4I15/2 (Ho31) 5I6!5I8/(Er31) 4I13/2!4I15/2

H4!3H6/ D2!3F4 3 H4!3H6/ 1 G4!3H6 7 F0!5D0 (excitation) 3 1

5

D0!7F2/stilbene dye emission

887/817 887/1545 1177/ 1545 815/454 815/460 815/656 579.4/ 579.9 611/412

[92]

[96] [97]

(Continued)

Table 10.1 (Continued) T-range (K)

Transitions

λ (nm)

Ref.

4.9

150

10 2 350

(Tb31) 5D4!7F5/(Eu31) 5D0!7F2

545/612

[98]




4.5

295

278 2 318

Fluorescein/Texas Red emission

518/610

[99]




1.8

330

293 2 363

Fullerene C70 /perylene emission

470/700

[100]





1.3 0.66

318 293

293 2 373 293 2 298

Excitonic emission (intensity ratio) CdSe-CdS/Alexa-647 emission

500/575 635/670

[101] [102]





B0.23

473 333

373
473 293
333

LSPR/TSPR (absorption) Trap emission (lifetime) (bandwidth)

B800/540 530

[103] [104]

Dopant ions

[Eu/Tb(btfa)3 (MeOH) (bpeta)] complex Fluorescein D/Texas Red-A in DNA Fullerene C70 in PtBMA ZnMnSe/ZnCdSe CdSe/CdS with Alexa647 dye Gold nanorods Carbon dots

Eu31, Tb31



Sr MAX (%K21)

T (K)

Host

B0.2 B0.15

LSPR, longitudinal surface plasmon resonance; TSPR, transverse surface plasmon resonance.

Pressure and temperature optical sensors

10.5

253

High-pressure measurements—general remarks

All of the experiments performed under high-pressure conditions, that is, structural, spectroscopic, and magnetic measurements are based on the materials compression. This leads to the decrease of their unit cell volume, change of the crystal lattice parameters, bond shortening, formation of crystal defects, phase transitions, amorphization, and alterations of symmetry of the local coordination environment [1,2,34,105
108]. It is very important to check whether the pressure-induced changes and distortions were caused by the plastic or elastic deformations of the compressed structures. The reversibility of such effects can be determined, performing the measurements at compression
decompression cycles (pressure release). However, usually the materials compressed reveal some hysteretic effects of their structural and spectroscopic properties, after the full compression
decompression cycle [1,2,6,34,105,106].

10.5.1 Pressure chamber In order to study the influence of high pressure on the spectroscopic properties of the materials, the experiments are usually performed in a DAC. Such DAC chamber (Fig. 10.11) usually consists of metal cover, closed with screws, metal gasket (usually made of stainless steel or tungsten carbide), two diamonds, a pressure sensor (e.g., a small piece of ruby), and a hydrostatic pressure-transmitting medium providing uniform distribution of forces/pressure in the DAC chamber. The very small amount of the investigated sample (size B100
500 μm) is situated inside of the hole drilled in a metal gasket, placed between two opposite diamond anvils. To compress the sample, the screws are tightened, causing elevation of the pressure in the chamber. Alternatively, a membrane cell can be used to generate the pressure by introduction of a gas (usually helium) into a metal balloon, which also leads to compression of the material situated inside the hole in the metal gasket. Owing to the high hardness/durability and transparency of diamonds, it is possible to online monitor the spectroscopic and structural alterations of the compressed materials, as a function of the applied pressure. The spectroscopic (luminescence) studies are often performed in the pressure range up to B30 GPa (300,000 bar), where most of the photophysical changes can be well observed in the materials studied. This pressure range is usually the most useful, as it conforms and fits the potential further practical/industrial applications of the materials studied. At higher pressure values, the irreversible amorphization of the samples is often observed, which is usually not beneficial for the materials studied [105,106].

10.5.2 Pressure-transmitting medium It is important to select and use the appropriate pressure-transmitting medium to perform the measurements at hydrostatic or quasihydrostatic conditions. Usually, the methanol/ethanol/water (16/3/1) solvent system or silicon oil is used as the

254

Handbook of Nanomaterials in Analytical Chemistry

Figure 10.11 Different screw-driven and membrane diamond anvil cells (DACs)—pressure chambers.

pressure-transmitting medium. The first one is hydrostatic up to B10.5 GPa, whereas the silicon oil has hydrostaticity limits of few GPa, depending on its composition. Alternatively, the liquid gases can be used as pressure-transmitting media, where liquid helium has the highest hydrostaticity limit of above B30 GPa. However, operating and processing with gases for DAC loading is not straightforward and require additional special apparatus. The measurements performed under nonhydrostatic conditions may be not perfectly repeatable and reproducible (e.g., the reported pressure values of phase transitions may differ between the studied). This is due to the different and nonhomogenous stress applied to the compressed crystals.

10.6

High-pressure luminescence measurements

10.6.1 Diamonds Before starting the high-pressure luminescence measurements, one must consider the use of proper diamond anvils. The diamonds with smaller culet size (,500 μm)

Pressure and temperature optical sensors

255

allow achieving higher values of pressure during the experiment. However, they also force the use of smaller hole in a gasket (chamber), equals to smaller sample size (,250 μm) and lower luminescence signal. If the sample has high quantum efficiency and bright emission, its small size is not a problem, worse is if one deals with, for example, UC materials of low QY and hardly observed luminescence. Moreover, the luminescence intensity usually decreases with pressure (due to the quenching effects, which will be discussed later), as limiting the acquisition of high-quality data at extremely high-pressure values. It is also of crucial importance to select the proper quality/purity of diamonds. Currently, most of the researchers use natural or synthetic diamonds, called as Ia (typical for XRD, magnetic, and some spectroscopic studies), IIac (ultralow fluorescence), and IIas (ultralow fluorescence and birefringence). All of them are transparent in the visible and NIR range. The Ia diamonds are the cheapest ones, but they are not suitable for FT-IR and Raman spectroscopies due to their absorption in the mid-infrared (4000
400 cm21). They also have absorption threshold below B320 nm. Hence, for the far UV-excited photoluminescence measurements, it is recommended to use IIac or IIas diamonds.

10.6.2 Source of excitation light One must also consider the use of appropriate light source for sample excitation. Owing to the small size of the sample, deuterium lamps (for UV excitation) and CW or pulsed lasers (both lasers for UV
Vis
NIR excitation) are usually applied. These light sources can provide small spatial size of the beam, which is necessary to guarantee the most effective excitation, related to the small sample size. It is worth noting that using the pulsed fs or ns laser (e.g., OPO - optical parametric oscillator), one must be very careful, as it is very easy to damage and simply burn the diamonds with highly energetic laser pulses. Hence, some safe distance from the focal point is recommended, and should be preserved during the measurements, where the focused pulsed laser beam is used.

10.6.3 Detection geometry Finally, the desired geometric configuration should be chosen for the particular measurements. One option is to use the back illuminated detection geometry (transmitting mode). In that case, the light beam is focused on the sample, and the emission signal is collected from the opposite side of the DAC. Alternatively, the luminescence signal can be detected from the same side as the excitation light (schematically shown in Fig. 10.12), with 30
90 degrees detection geometry (depending also on the DAC opening angle). The second option provides higher intensity signal, as more emitted photons reach the detector (they are coming directly from the sample surface, and do not have to penetrate through its whole volume). In both cases, the light coming out from the sample, that is, luminescence signal is focused with the lens on the slit, and reaches the detector (CCD camera or PMT).

256

Handbook of Nanomaterials in Analytical Chemistry

Figure 10.12 Schematic setup configuration for high-pressure luminescence measurements of the materials compressed in DAC.

The Raman spectrometers, equipped with confocal microscope and appropriate laser (usually 532 nm), are very sensitive devices, which are also used for some luminescence measurements and rapid pressure determination [23].

10.6.4 Pressure determination—optical sensors In the case of the optical pressure gauges (noncontact sensors), using the pressuredependent emission of some optically active ions, embedded in various crystal matrices (based on Barnett et al.’s [109] ideas of an ideal sensor) Tro¨ster [107] has proposed some ideal requirements, which should be fulfilled, namely 1. spectrum measured should consist of a single line with no significant broadening or weakening with pressure; 2. emission line should show a large spectral shift with pressure (dλ/dP); 3. temperature dependence of the line shift should be as small as possible (dλ/dT); 4. linewidth Γ (FHWM) should be small, in comparison to the line shift (Γ21 dλ/dP), in order to provide high sensitivity and precision of pressure determination; 5. host lattice must exhibit a significant structural stability under high temperature and pressure conditions; 6. optically active ions should have absorption bands in the spectral range of the emission of commercial lasers, to ensure low cost and easy excitation.

Nowadays, the most commonly used method for optical determination of pressure in a DAC’s chamber is based on the measurements of a ruby R1 line fluorescence shift (dλ/dP B0.35 nm GPa21; dΓ/dP B0.5
0.8 nm GPa21) [110
112]. This is because of its high sensitivity and good spectral resolution, simple measurement by using any kind of spectrometer (with PMT or CCD detector), availability of the excitation source in the range of B350
600 nm (often a 532-nm green laser

Pressure and temperature optical sensors

257

is used), abundance of synthetic and natural ruby crystals, as well as the available pressure calibrations up to very high values ( . 100 GPa) [110
112]. The first calibration up to 2.3 GPa (using the freezing point of some liquids) and the use of ruby as a pressure sensor has been done in 1972 by Forman et al. [110]. After that time, the interest of performing high-pressure experiments in DAC and using ruby as a pressure sensor has been growing. Currently, the most frequently used pressure calibrations of ruby are the ones made by Mao et al. [111] in 1986, up to B80 GPa, using shock-wave equation of state (EoS) of copper and silver, and by Dewaele et al. [112] in 2008, up to B200 GPa, using EoS of iron, cobalt, nickel, zinc, molybdenum, and silver. Unfortunately, the main drawbacks of ruby are its significant temperature dependence of the emission line shift (dλ/dT B0.0068 nmK21), large broadening, and overlapping of the R1 and R2 lines above B573K, hampering accurate pressure determination in the DAC [1,113]. Moreover, the bands overlapping and significant intensity decrease are usually observed also at ambient temperature, above B20 GPa. This is because of the nonhydrostaticity of the most commonly used pressure-transmitting media (e.g., methanol/ethanol/water and silicon oils) in that pressure range [23,114]. Hence, there is an outstanding interest in the lanthanide-based pressure sensors, in order to overcome the mentioned drawbacks and limits of the pressure determination at high-temperature conditions. That is why, the high-pressure luminescence of the potential optical sensors, based on the Ce31, Nd31, Sm31, Eu31, Er31, and Tm31 doped materials, has been studied [1,2,107,115
119]. Notwithstanding, the Sm21 ion, which has the same electronic structure of the energy levels as Eu31 ion, seems to be currently one of the best candidates as high-pressure sensor, thanks to its favorable luminescence properties, that is, extremely narrow emission band and high-pressure sensitivity (large shift of the 0-0 emission line). Sm21-doped SrFCl microcrystals, exhibiting superior sensitivity (dλ/dP B1.1 nm GPa21), have been proposed as a pressure sensor by Shen et al. [120] and Lorenz et al. [121]. Unfortunately, this material has relatively strong temperature dependence of the emission band shift (dλ/dT B0.0023 nm K21), and a very high-pressure-induced deterioration of its emission intensity, which limits its use to a relatively low pressure range, below B20 GPa [107,121]. Fortunately, such compounds as strontium borates can very well stabilize the Sm21 ions, with negligible temperature dependence and a moderate-pressure-induced intensity decrease, allowing their use both at very high pressure and elevated temperature conditions. Strontium borates doped with Sm21 ions are synthesized at high-temperature conditions, in a reducing atmosphere, forming complex crystals, such as Sm21-doped SrB2O4, SrB4O7, Sr2(B2O5), Sr3(B2O6), and SrB6O10, which are thermally stable up to above 103K [23,113,114,122
125]. Among them, the most commonly studied and used pressure sensor is Sm21-doped SrB4O7, which exhibits high sensitivity and a very narrow (dλ/dP B0.25 nm GPa21; Γ B0.1
0.2 nm), well separated, intense single emission line around 685.5 nm, which corresponds to the 5D0!7F0 transition, and it is almost insensitive to temperature variations (dλ/dT B1024 nm K21) [113,125].

258

Handbook of Nanomaterials in Analytical Chemistry

That material, obtained in a form of microcrystals, has been calibrated as a pressure sensor by Datchi et al. [113,114] and Rashchenko et al. [125], up to above 100 GPa. However, the currently utilized sensors based on the Sm21-doped SrB4O7 compound are commonly synthesized as microcrystals, which are impured with a second phase of SrB2O4 crystals, as well as a mixture of meta- and tetra-borate structures [113,114,122,123,125,126]. The presence of mixed borate phases, that is, the nonhomogeneous material may result in the observed discrepancies in the pressure calibration, discouraging the potential users from replacing ruby by the Sm21doped sensors [23]. Moreover, the “micro” size of both ruby and strontium borates microcrystals limits their spatial resolution and do not allow application in submicro scale.

10.7

Optical nanosensors of pressure—nanomanometry

To overcome the size limitations, increase the spatial resolution of pressure determination and simplify DACs loading (e.g., by easy injection of the colloidal nanosensor), high-pressure luminescence phenomena of the Ln21/31-doped nano-sized materials are currently studied [1,2,6,23,34,105,118,127]. The compression of lanthanide-based materials under high-pressure conditions is usually performed in a DAC, and leads to the spectral shift of their absorption/emission bands (blue/redshift), changes in band intensity ratios, bands broadening, prolonged/shortened luminescence lifetimes, etc. [1,2,6,23,34,107,108,110,128]. These changes can be used for pressure calibrations purposes (nanomanometry) [1,2,23]. It is worth noting that compression of the materials influences their luminescence intensity, which usually continuously decreases with pressure. This is due to the increased probability of energy transfer cross-relaxation processes between the emitting ions, when interionic distances decrease, as well as enhanced multiphonon relaxation in the compressed materials [1,2,23,34,107,108]. The latter effect is a result of the pressure-induced increase of the phonon energies, resulting in an enhanced electron
phonon coupling [1]. That is why, it is of crucial importance to select as a potential pressure sensor, the material exhibiting intense luminescence signal (high QY), to be able to easily and accurately determine the pressure values under extreme conditions. To the best of my knowledge, currently (2018) there are only three reports concerning the use of NPs for the contactless, optical pressure sensing purposes, hence they will be discussed in more detail here. Recently Runowski et al. [23] reported the synthesis protocol and spectroscopic characteristics of new contactless nanosensor of pressure, based on the luminescence red-shift of the SrB2O4:Sm21 1 mol.% NPs (dλ/dP B0.244 nm GPa21; Γ B0.15 nm). The compound synthesized was a pure, single-phase product (orthorhombic), crystallizing in a form of elongated NPs, whose size was in the range of

Pressure and temperature optical sensors

259

Figure 10.13 TEM image of the SrB2O4:Sm21 NPs. Source: Reprinted from M. Runowski, P. Wo´zny, V. Lavı´n, S. Lis, Optical pressure nanosensor based on lanthanide-doped SrB2O4:Sm21 luminescence
novel high-pressure nanomanometer, Sens. Actuat. B Chem. 273 (2018) 585
591 with permission from Elsevier.

B100
200 nm in width and B500 nm in length (Fig. 10.13), forming aqueous colloidal solutions. The SrB2O4:Sm21 nanocrystals were prepared by a modified Pechini method [55], by mixing the appropriate amounts of aqueous solutions of lanthanides and strontium salts (nitrates and chlorides) with citric acid, ethylene glycol, and boric acid. The final product in a form of fine, white powder was obtained by two-step annealing in a furnace, at 573K (2 h) and then at 1173K (3 h). The obtained nanomaterial could be excited in a broad spectral range, from 200 to 550 nm. Its emission spectrum was composed of narrow bands, in the range from 680 to 780 nm, corresponding to 4f6
4f6 transitions, that is, 5D0!7F0 (B685 nm), 5D0!7F1 (B700 nm), 5D0!7F2 (B730 nm), and 5D0!7F3 (B765 nm), characteristic for Sm21 ion. All of the bands red-shifted with pressure (Fig. 10.14), which is typical for Ln21/31 ions, and it is related to the decreasing energy difference between their ground and excited states, along with increasing pressure. This is due to the shortening of interionic Sm-O distances and stronger interactions between the ions, resulting from the reduction of free ion parameter, leading to the expansion of wave function (nephelauxetic effect), which increases the covalency character of the bonds, and an increase of the crystal-field strength [107,108]. The authors calibrated the synthesized SrB2O4:Sm21 nanosensor (using ruby as a reference), up to above 25 GPa (Fig. 10.15), in compression
decompression

260

Handbook of Nanomaterials in Analytical Chemistry

Figure 10.14 Normalized emission spectra of the SrB2O4:Sm21 NPs as a function of pressure; λex 5 532 nm. Source: Reprinted from M. Runowski, P. Wo´zny, V. Lavı´n, S. Lis, Optical pressure nanosensor based on lanthanide doped SrB2O4:Sm21 luminescence
novel high-pressure nanomanometer, Sens. Actuat. B Chem. 273 (2018) 585
591 with permission from Elsevier.

Figure 10.15 Pressure calibration curve based on the spectral position of 5D0!7F0 emission peak as a function of pressure for the SrB2O4:Sm21 NPs. The filled symbols represent the compression and the empty ones decompression data. Source: Adapted from M. Runowski, P. Wo´zny, V. Lavı´n, S. Lis, Optical pressure nanosensor based on lanthanide doped SrB2O4:Sm21 luminescence
novel high-pressure nanomanometer, Sens. Actuat. B Chem. 273 (2018) 585
591 with permission from Elsevier.

Pressure and temperature optical sensors

261

cycles, using a reversible red-shift of the 5D0!7F0 emission line (0-0) of Sm21 (0.244 nm GPa21). The pressure sensitivity of the studied nanosensor is similar to the SrB4O7:Sm21 microcrystals (dλ/dP B0.25 nm GPa21) [114,125,126], and slightly lower compared to ruby (dλ/dP B0.35 nm GPa21) [110
112]. Thanks to the very sharp emission line (0
0) used for pressure determination and its highpressure sensitivity, the accuracy of pressure sensing with SrB2O4:Sm21 NPs was approximately 6 0.01 GPa. The prepared SrB2O4:Sm21 NPs presented a very low temperature dependence, with the 0
0 line shift dλ/dT B0.0001 nm K21, as well as almost negligible temperature-induced broadening (dΓ/dP B2.3 3 1024 nm K21) and several times smaller thermal quenching of luminescence (B30% of the initial intensity at 573K), compared to ruby sensors. The small size of the obtained NPs guarantees high spatial resolution of the nanosensor, allowing its use in submicro-sized areas, same as a dry powder and a colloid. The other pressure nanosensor, based on the UC luminescence of LaPO4:20% Yb31-0.5% Tm31 NPs (B70
150 nm), obtained via a simple coprecipitation and a subsequent postsynthesis thermal annealing (1273K) method, was investigated by Runowski et al. [1]. The authors correlated the reversible UC emission line redshift of the most intense band at 475 nm (1G4!3H6), and the change of the band ratio 800/475 nm (3H4!3H6/1G4!3H6) with pressure, using λex 5 975 nm. The monitored band at 475 nm shifted with a rate dλ/dP B0.1 nm GPa21 (B4.8 cm21 GPa21), whereas the band ratio changed from about 0.6 to 1.8 (approximately three times), in the pressure range studied, that is, from ambient up to B25 GPa. However, the estimated accuracy of those methods, that is, about 6 1 GPa allowed rather rough estimation of the pressure value. On the other hand, the obtained nanosensor was bifunctional, allowing precise and accurate determination of temperature of the simultaneously heated and compressed system under high-pressure conditions, which was already mentioned in the part concerning temperature nanosensors. The another approach for pressure sensing was the use of pressure dependence of the UC emission lifetimes of the SrF2:Yb31
Er31 NPs (B50
100 nm), reported by Runowski et al. [2]. Fig. 10.16 shows TEM image of the synthesized NPs. The authors correlated with pressure the fully reversible shortening of the UC emission lifetimes (determined based on the recorded UC luminescence decay curves) of Er31 ion, for three transitions, that is, 4F9/2!4I15/2 at 653 nm (shortening from 220 to 130 μs), 4S3/2!4I15/2 at 538 nm (62.5 to 41.5 μs) and 2H11/2!4I15/2 transition at 516 nm (63.0 to 42.5 μs). The obtained lifetime values were correlated with pressure using the second-order polynomial, with R2 . 0.99 (Fig. 10.17). The measurements were performed in the pressure range from ambient up to 5.29 GPa, where no phase transition was observed. The theoretical calculations performed by the authors suggested that the pressure-induced shortening of the UC emission lifetime values in the SrF2:Yb31, Er31 NPs, were mainly caused rather by energy transfer processes (effective rate of direct, back-transfer, and cross-relaxation), than

262

Handbook of Nanomaterials in Analytical Chemistry

Figure 10.16 TEM image of the synthesized SrF2:Yb31, Er31 NPs. Source: Reprinted from M. Runowski, J. Marciniak, T. Grzyb, D. Przybylska, A. Shyichuk, B. Barszcz, A. Katrusiak, S. Lis, Lifetime nanomanometry
high-pressure luminescence of up-converting lanthanide nanocrystals
SrF2:Yb31,Er31, Nanoscale 9 (2017) 16030
16037. Published by The Royal Society of Chemistry.

by multiphonon relaxation. The authors further used the calibrated nanosensor for determination of the critical pressure of the phase transition (B0.5 GPa) in urea crystals, with accuracy of about 6 0.1 GPa. Owing to the intense UC luminescence of the system and the use of time-resolved method, they could probe the pressure using a diluted colloidal solution of NPs, at concentration down to 0.1% (1 mg mL21). The benefits of using UC lifetime nanomanometry are as follows: the use of NIR excitation light, which is highly penetrable for many systems; small size of the NPs guaranteeing high spatial resolution of the pressure sensors; elimination of the background fluorescence, thanks to the use of time-resolved method with relatively long emission lifetime and NIR excitation; convenient way of processing (DAC loading), as a luminescent colloid can be easily injected and is uniformly distributed in the DAC chamber. Table 10.2 presents a comparison of bulk and nano-sized materials, used as pressure sensors, based on the luminescence of Ln21/31 or Cr31 ions, emphasizing their performance, that is, pressure sensitivity and temperature dependence. The sensitivity is usually expressed as a pressure-induced line shift (nm GPa21), but also as a relative change (in percent) of other measured parameters, that is, band ratio and lifetime.

Pressure and temperature optical sensors

263

Figure 10.17 Luminescence decay curves (left) and determined emission lifetimes (right) for the SrF2:Yb31, Er31 sample at high pressure; λex 5 980 nm, λem 5 653, 538 and 516 nm for 4 F9/2!4I15/2, 4S3/2 !4I15/2, and 2H11/2 !4I15/2 transitions, respectively. Source: Reprinted from M. Runowski, J. Marciniak, T. Grzyb, D. Przybylska, A. Shyichuk, B. Barszcz, A. Katrusiak, S. Lis, Lifetime nanomanometry
high-pressure luminescence of up-converting lanthanide nanocrystals
SrF2:Yb31,Er31, Nanoscale 9 (2017) 16030
16037 Published by The Royal Society of Chemistry.

10.8

Concluding remarks

High pressure and temperature significantly influence electronic properties of the materials studied. Performing the experiments under extreme conditions of pressure and temperature, one may investigate the continuous changes of the unit cell volume, bond strength, geometry changes, vibrational properties, electron
phonon interactions, energy transfer phenomena, changes in the energy of the transitions, thermalization of the states, etc.

Table 10.2 Pressure sensitivities (line shift) and the related temperature dependences of different bulk and nano-sized materials doped with Ln21/31 or Cr31 ions, used as optical pressure sensors; spectral range of the transitions used and the corresponding references. Host

Dopant ion

Line shift (nm GPa21)

T-shift (nmK21)

Transitions

λ (nm)

Ref.

Al2O3 (ruby) YAlO3 YAlO3 Y3Al5O12 (YAG) Y3Al5O12 (YAG) SrFCl SrB4O7 (nano) SrB2O4 (nano) LaPO4 (nano) LaPO4 (nano) SrF2

Cr31 Cr31 Nd31 Eu31 Sm31 Sm21 Sm21 Sm21 Tm31 Tm31 Er31

6.8 3 1023 7.6 3 1023 1 3 1026 25.4 3 1024 2.3 3 1024 22.3 3 1023 21 3 1024 21 3 1024 22 3 1023



2

E!4A2 E!4A2 4 F3/2!4I9/2 (Stark) 5 D0!7F1 4 G5/2!6H7/2 (Stark) 5 D0!7F0 5 D0!7F0 5 D0!7F0 1 G4!3H6 3 H4!3H6/1G4!3H6 4 F9/2 !4I15/2 4 S3/2 !4I15/2 2 H11/2 !4I15/2

694 723 875 591 618 690 685 685 475 800/475 653 538 516

[111] [109] [109] [116] [129] [120] [114] [23] [1] [1] [2]

Y6Ba4(SiO4)6F2 (fluorapatite)

Ce31

0.365 0.70 2 0.13 0.197 0.30 1.10 0.255 0.244 0.1 8%/GPa (band ratio) 7.7%/GPa 6.4%/GPa 6.2%/GPa (lifetimes) 0.63 (shift) 1.5% (width) 2.5% (width)




2

DJ !2FJ (5d!4f) Emission 2 FJ!2DJ (4f!5d) excitation

466 342

[115]

2

Pressure and temperature optical sensors

265

Among various organic, metal complexes, quantum dots, bulk materials, etc., the inorganic lanthanide-doped nanomaterials seem to be the best candidates for the modern pressure and temperature nanosensors. This is due to their superior properties, such as long luminescence lifetimes, narrow emission bands, thermal and pressure stability, resistance to photobleaching and photodegradation, ladderline structure of the energy levels, ability to generate efficient UC luminescence (NIR excitation), emission in the first, second, and third biological windows, facile preparation and stability of their aqueous colloids, relatively low cytotoxicity and easy surface functionalization (e.g., core/shell structure), which guarantee their biocompatibility and possibility of application in various biological and medical purposes. The existing pressure and temperature sensors based on lanthanide luminescence work on the basis of the detectable pressure and temperature-induced changes of their spectral position of absorption/emission bands (line shift), band ratio, intensity changes, bandwidth, lifetimes, etc. However, currently there are neither optimal nanosensor of pressure nor temperature, as each one has some previously discussed limitations. The most desired one would be the bifunctional sensor of pressure and temperature, which should exhibit simultaneously some temperature-dependent properties, such as the presence of thermalized levels, favorably insensitive to the pressure changes, and for example, pressure-dependent emission line shift with negligible or well-defined temperature dependence. This is because of the crucial importance of the pressure
temperature interdependences (pressure
temperature phase diagrams), allowing the formation of new material/phases at extreme conditions of both factors, as well as at mild pressure (under elevated temperature) or at mild temperature (under elevated pressure), where the use of such bifunctional sensor would be highly desired [1,107,130]. That is why, performing the experiments and investigating new potential sensors of the discussed state functions, one should keep in mind the possible influence of other factors such as pressure
temperature interdependences, influence of the medium used, power and excitation wavelength of the light source used (the availability of the excitation light and the detectors used should be considered), spectral range of the emitted light for facile and effective detection (e.g., in biological windows), biocompatibility/cytotoxicity in the case of bioapplications, etc. Other very important factors, which are often forgotten are repeatability and reproducibility of the measurements, including the pressure/ temperature stability of the materials used. The potential optical nanosensor should not be reactive, photodegradable, easily decompose, oxidase, undergo phase transitions, etc. Obviously the improvement of the sensors sensitivity, accuracy, precision, temporal, and spatial resolution are always desirable.

References [1] M. Runowski, A. Shyichuk, A. Tymi´nski, T. Grzyb, V. Lavı´n, S. Lis, Multifunctional optical sensors for nanomanometry and nanothermometry: high-pressure and hightemperature upconversion luminescence of lanthanide-doped phosphates—LaPO4/YPO4: Yb31
Tm31, ACS Appl. Mater. Interfaces 10 (2018) 17269
17279.

266

Handbook of Nanomaterials in Analytical Chemistry

[2] M. Runowski, J. Marciniak, T. Grzyb, D. Przybylska, A. Shyichuk, B. Barszcz, et al., Lifetime nanomanometry
high-pressure luminescence of up-converting lanthanide nanocrystals
SrF2:Yb31,Er31, Nanoscale 9 (2017) 16030
16037. [3] H. Yu, J. Li, R.A. Loomis, L.-W. Wang, W.E. Buhro, Two- versus three-dimensional quantum confinement in indium phosphide wires and dots, Nat. Mater. 2 (2003) 517
520. [4] B.M. van der Ende, L. Aarts, A. Meijerink, Lanthanide ions as spectral converters for solar cells, Phys. Chem. Chem. Phys. 11 (2009) 11081
11095. [5] A. Gnach, A. Bednarkiewicz, Lanthanide-doped up-converting nanoparticles: merits and challenges, Nano Today 7 (2012) 532
563. [6] P. Wo´zny, M. Runowski, S. Lis, Emission color tuning and phase transition determination based on high-pressure up-conversion luminescence in YVO4: Yb31, Er31 nanoparticles, J. Lumin. 209 (2019) 321
327. [7] J. Liu, S.Z. Qiao, J.S. Chen, X.W. Lou, X. Xing, G.Q. Lu, Yolk/shell nanoparticles: new platforms for nanoreactors, drug delivery and lithium-ion batteries, Chem. Comm. 47 (2011) 12578
12591. [8] S. Ranjan, M.K.G. Jayakumar, Y. Zhang, Luminescent lanthanide nanomaterials: an emerging tool for theranostic applications, Nanomedicine 10 (2015) 1477
1491. [9] K. Ostrikov, E.C. Neyts, M. Meyyappan, Plasma nanoscience: from nano-solids in plasmas to nano-plasmas in solids, Adv. Phys 62 (2013) 113
224. [10] V. Skumryev, S. Stoyanov, Y. Zhang, G. Hadjipanayis, D. Givord, J. Nogue´s, Beating the superparamagnetic limit with exchange bias, Nature 423 (2003) 850
853. [11] K. Kamala Bharathi, N.R. Kalidindi, C.V. Ramana, Grain size and strain effects on the optical and electrical properties of hafnium oxide nanocrystalline thin films, J. Appl. Phys. 108 (2010) 083529. [12] W. Park, D. Lu, S. Ahn, Plasmon enhancement of luminescence upconversion, Chem. Soc. Rev. 44 (2015) 2940
2962. [13] Y. Liu, D. Tu, H. Zhu, X. Chen, Lanthanide-doped luminescent nanoprobes: controlled synthesis, optical spectroscopy, and bioapplications, Chem. Soc. Rev. 42 (2013) 6924
6958. [14] E.C. Ximendes, A.F. Pereira, U. Rocha, W.F. Silva, D. Jaque, C. Jacinto, Thulium doped LaF3 for nanothermometry operating over 1000 nm, Nanoscale 11 (2019) 8864
8869. [15] M. Runowski, N. Stopikowska, D. Szeremeta, S. Goderski, M. Skwierczy´nska, S. Lis, Upconverting lanthanide fluoride core@shell nanorods for luminescent thermometry in the first and second biological windows: β-NaYF4:Yb31
Er31@SiO2 temperature sensor, ACS Appl. Mater. Interfaces 11 (2019) 13389
13396. [16] Z. Tang, N. a Kotov, M. Giersig, Spontaneous organization of single CdTe nanoparticles into luminescent nanowires, Science 297 (2002) 237
240. [17] C.M. Hussain, Handbook of Nanomaterials for Industrial Applications, Elsevier, 2018. [18] C.M. Hussain, Nanomaterials in Chromatography: Current Trends in Chromatographic Research Technology and Techniques, Elsevier, 2018. [19] P.A. Tanner, Some misconceptions concerning the electronic spectra of tri-positive europium and cerium, Chem. Soc. Rev. 42 (2013) 5090
5101. [20] A. Shyichuk, R.T. Moura, A.N. Carneiro Neto, M. Runowski, M.S. Zarad, A. Szczeszak, et al., Effects of dopant addition on lattice and luminescence intensity parameters of Eu(III)-doped lanthanum orthovanadate, J. Phys. Chem. C 120 (2016) 28497
28508.

Pressure and temperature optical sensors

267

[21] K. Binnemans, Lanthanide-based luminescent hybrid materials, Chem. Rev. 109 (2009) 4283
4374. [22] B.G. Wybourne, L. Smentek, Optical Spectroscopy of Lanthanides, CRC Press, New York, 2007. [23] M. Runowski, P. Wo´zny, V. Lavı´n, S. Lis, Optical pressure nano-sensor based on lanthanide doped SrB2O4:Sm21 luminescence
Novel high-pressure nanomanometer, Sens. Actuat. B Chem. 273 (2018) 585
591. [24] M.J. Weber, Probabilities for radiative and nonradiative decay of Er31 in LaF3, Phys. Rev. 157 (1967) 262
272. [25] M. Runowski, A. Bartkowiak, M. Majewska, I.R. Martı´n, S. Lis, Upconverting lanthanide doped fluoride NaLuF4:Yb31-Er31-Ho31 - optical sensor for multi-range fluorescence intensity ratio (FIR) thermometry in visible and NIR regions, J. Lumin. 201 (2018) 104
109. [26] F. Auzel, Upconversion and anti-stokes processes with f and d ions in solids, Chem. Rev. 104 (2004) 139
173. [27] H. Dong, L. Sun, C. Yan, Energy transfer in lanthanide upconversion studies for extended optical applications, Chem. Soc. Rev. 44 (2015) 1608
1634. [28] D. Jaque, F. Vetrone, Luminescence nanothermometry, Nanoscale 4 (2012) 4301
4326. [29] C.D.S. Brites, P.P. Lima, N.J.O. Silva, A. Milla´n, V.S. Amaral, F. Palacio, et al., Thermometry at the nanoscale, Nanoscale. 4 (2012) 4799
4829. [30] C.D.S. Brites, A. Milla´n, L.D. Carlos, Lanthanides in luminescent thermometry, Handb. Phys. Chem. Rare Earths 49 (2016) 339
427. [31] L.D. Carlos, F. Palacio (Eds.), Thermometry at the Nanoscale, Royal Society of Chemistry, Cambridge, 2015. [32] W. Zheng, P. Huang, D. Tu, E. Ma, H. Zhu, X. Chen, Lanthanide-doped upconversion nano-bioprobes: electronic structures, optical properties, and biodetection, Chem. Soc. Rev. 44 (2015) 1379
1415. [33] A. Nadort, J. Zhao, E.M. Goldys, Lanthanide upconversion luminescence at the nanoscale: fundamentals and optical properties, Nanoscale. 8 (2016) 13099
13130. [34] M.D. Wisser, M. Chea, Y. Lin, D.M. Wu, W.L. Mao, A. Salleo, et al., Strain-induced modification of optical selection rules in lanthanide-based upconverting nanoparticles, Nano Lett. 15 (2015) 1891
1897. [35] S.F. Leo´n-Luis, U.R. Rodrı´guez-Mendoza, E. Lalla, V. Lavı´n, Temperature sensor based on the Er31 green upconverted emission in a fluorotellurite glass, Sens. Actuat. B 158 (2011) 208
213. [36] M. Kamimura, T. Matsumoto, S. Suyari, M. Umezawa, K. Soga, Ratiometric nearinfrared fluorescence nanothermometry in the OTN-NIR (NIR II/III) biological window based on rare-earth doped β-NaYF4 nanoparticles, J. Mater. Chem. B. 5 (2017) 1917
1925. [37] S. Balabhadra, M.L. Debasu, C.D.S. Brites, R.A.S. Ferreira, L.D. Carlos, Upconverting nanoparticles working as primary thermometers in different media, J. Phys. Chem. C 121 (2017) 13962
13968. [38] M.A. Herna´ndez-Rodrı´guez, A.D. Lozano-Gorrı´n, I.R. Martı´n, U.R. Rodrı´guezMendoza, V. Lavı´n, Comparison of the sensitivity as optical temperature sensor of nano-perovskite doped with Nd31 ions in the first and second biological windows, Sens. Actuat. B 255 (2018) 970
976.

268

Handbook of Nanomaterials in Analytical Chemistry

[39] P. Cortelletti, A. Skripka, C. Facciotti, M. Pedroni, G. Caputo, N. Pinna, et al., Tuning the sensitivity of lanthanide-activated NIR nanothermometers in the biological windows, Nanoscale 10 (2018) 2568
2576. [40] D. Wawrzynczyk, A. Bednarkiewicz, M. Nyk, W. Strek, M. Samoc, Neodymium(III) doped fluoride nanoparticles as non-contact optical temperature sensors, Nanoscale 4 (2012) 6959
6961. [41] A. Benayas, B. del Rosal, A. Pe´rez-Delgado, K. Santacruz-Go´mez, D. Jaque, G.A. Hirata, et al., Nd:YAG Near-Infrared Luminescent Nanothermometers, Adv. Opt. Mater. 3 (2015) 687
694. ´ .J. De La Fuente, P.H. Gonzalez, U. [42] E. Carrasco, B. Del Rosal, F. Sanz-Rodrı´guez, A Rocha, et al., Intratumoral thermal reading during photo-thermal therapy by multifunctional fluorescent nanoparticles, Adv. Funct. Mater. 25 (2015) 615
626. [43] S. Balabhadra, M.L. Debasu, C.D.S. Brites, L.A.O. Nunes, O.L. Malta, J. Rocha, et al., Boosting the sensitivity of Nd31-based luminescent nanothermometers, Nanoscale 7 (2015) 17261
17267. [44] S. Zhou, G. Jiang, X. Wei, C. Duan, Y. Chen, M. Yin, Pr31-doped β-NaYF4 for temperature sensing with fluorescence intensity ratio technique, J. Nanosci. Nanotech. 14 (2014) 3739
3742. [45] M.S. Pudovkin, O.A. Morozov, V.V. Pavlov, S.L. Korableva, E.V. Lukinova, Y.N. Osin, et al., Physical background for luminescence thermometry sensors based on Pr31: LaF3 crystalline particles, J. Nanomater. 2017 (2017) 1
9. [46] A.D. Lozano-Gorrı´n, U.R. Rodrı´guez-Mendoza, V. Venkatramu, V. Monteseguro, M.A. Herna´ndez-Rodrı´guez, I.R. Martı´n, et al., Lanthanide-doped Y3Ga5O12 garnets for nanoheating and nanothermometry in the first biological window, Opt. Mater. 84 (2018) 46
51. [47] E.N. Cero˜n, D.H. Ortgies, B. Del Rosal, F. Ren, A. Benayas, F. Vetrone, et al., Hybrid nanostructures for high-sensitivity luminescence nanothermometry in the second biological window, Adv. Mater. 27 (2015) 4781
4787. [48] S. Zhou, X. Wei, X. Li, Y. Chen, C. Duan, M. Yin, Temperature sensing based on the cooperation of Eu31 and Nd31 in Y2O3 nanoparticles, Sens. Actuat. B Chem. 246 (2017) 352
357. [49] A. Bednarkiewicz, D. Wawrzynczyk, M. Nyk, W. Strek, Optically stimulated heating using Nd31 doped NaYF4 colloidal near infrared nanophosphors, Appl. Phys. B. 103 (2011) 847
852. [50] U. Rocha, K. Upendra Kumar, C. Jacinto, J. Ramiro, A.J. Caaman˜o, J. Garcı´a Sole´, et al., Nd31 doped LaF3 nanoparticles as self-monitored photo-thermal agents, Appl. Phys. Lett. 104 (2014) 053703. [51] H. Suo, X. Zhao, Z. Zhang, C. Guo, 808 nm Light-triggered thermometer
heater upconverting platform based on Nd31-sensitized yolk
shell GdOF@SiO2, ACS Appl. Mater. Interfaces 9 (2017) 43438
43448. [52] Z. Zhao, F. Hu, Z. Cao, F. Chi, X. Wei, Y. Chen, et al., Highly uniform and monodisperse β-NaYF4:Sm31 nanoparticles for a nanoscale optical thermometer, Opt. Lett. 43 (2018) 835. ´ [53] M.D. Drami´canin, Z. Anti´c, S. Culubrk, S.P. Ahrenkiel, J.M. Nedeljkovi´c, Selfreferenced luminescence thermometry with Sm31 doped TiO2 nanoparticles, Nanotechnology. 25 (2014). [54] I.E. Kolesnikov, E.V. Golyeva, E. L¨ahderanta, A.V. Kurochkin, M.D. Mikhailov, Ratiometric thermal sensing based on Eu31-doped YVO4 nanoparticles, J. Nanopart. Res. 18 (2016).

Pressure and temperature optical sensors

269

[55] M.U. Pechini, Method of preparing lead and alkaline earth titanates and niobates and coating method using the same to form a capacitor, No. 3330697, 1967. [56] F. Huang, D. Chen, Synthesis of Mn21:Zn2SiO4-Eu31:Gd2O3 nanocomposites for highly sensitive optical thermometry through the synergistic luminescence from lanthanide-transition metal ions, J. Mater. Chem. C 5 (2017) 5176
5182. [57] K. Zheng, Z. Liu, C. Lv, W. Qin, Temperature sensor based on the UV upconversion luminescence of Gd31 in Yb31
Tm31
Gd31 codoped NaLuF4 microcrystals, J. Mater. Chem. C 1 (2013) 5502
5507. [58] Z. Cao, S. Zhou, G. Jiang, Y. Chen, C. Duan, M. Yin, Temperature dependent luminescence of Dy31 doped BaYF5 nanoparticles for optical thermometry, Curr. Appl. Phys. 14 (2014) 1067
1071. ´ [59] S. Culubrk, V. Lojpur, S.P. Ahrenkiel, J.M. Nedeljkovi´c, M.D. Drami´canin, Non-contact thermometry with Dy31 doped Gd2Ti2O7 nano-powders, J. Lumin. 170 (2016) 395
400. [60] O.A. Savchuk, J.J. Carvajal, M.C. Pujol, E.W. Barrera, J. Massons, M. Aguilo, et al., Ho,Yb:KLu(WO4)2 nanoparticles: a versatile material for multiple thermal sensing purposes by luminescent thermometry, J. Phys. Chem. C 119 (2015) 18546
18558. [61] H. Li, Y. Zhang, L. Shao, Z. Htwe, P. Yuan, Luminescence probe for temperature sensor based on fluorescence intensity ratio, Opt. Mater. Express. 7 (2017) 1077. [62] M.A.R.C. Alencar, G.S. Maciel, C.B. de Arau´jo, A. Patra, Er31-doped BaTiO3 nanocrystals for thermometry: influence of nanoenvironment on the sensitivity of a fluorescence based temperature sensor, Appl. Phys. Lett. 84 (2004) 4753
4755. [63] S.K. Singh, K. Kumar, S.B. Rai, Er31/Yb31 codoped Gd2O3 nano-phosphor for optical thermometry, Sens. Actuators A Phys. 149 (2009) 16
20. [64] A. Sedlmeier, D.E. Achatz, L.H. Fischer, H.H. Gorris, O.S. Wolfbeis, Photon upconverting nanoparticles for luminescent sensing of temperature, Nanoscale 4 (2012) 7090
7096. [65] R.G. Geitenbeek, P.T. Prins, W. Albrecht, A. Van Blaaderen, B.M. Weckhuysen, A. Meijerink, NaYF4:Er31,Yb31/SiO2 core/shell upconverting nanocrystals for luminescence thermometry up to 900 K, J. Phys. Chem. C 121 (2017) 3503
3510. [66] H. Suo, X. Zhao, Z. Zhang, R. Shi, Y. Wu, J. Xiang, et al., Local symmetric distortion boosted photon up-conversion and thermometric sensitivity in lanthanum oxide nanospheres, Nanoscale 10 (2018) 9245
9251. [67] N.N. Dong, M. Pedroni, F. Piccinelli, G. Conti, A. Sbarbati, J.E. Ramı´rez-Herna´ndez, et al., NIR-to-NIR two-photon excited CaF2:Tm31,Yb31 nanoparticles: multifunctional nanoprobes for highly penetrating fluorescence bio-imaging, ACS Nano 5 (2011) 8665
8671. [68] S. Zhou, G. Jiang, X. Li, S. Jiang, X. Wei, Y. Chen, et al., Strategy for thermometry via Tm31-doped NaYF4 core-shell nanoparticles, Opt. Express. 39 (2014) 6687. [69] O.A. Savchuk, J.J. Carvajal, C. Cascales, J. Massons, M. Aguilo´, F. Dı´az, Thermochromic upconversion nanoparticles for visual temperature sensors with high thermal, spatial and temporal resolution, J. Mater. Chem. C 4 (2016) 6602
6613. [70] A.F. Pereira, K.U. Kumar, W.F. Silva, W.Q. Santos, D. Jaque, C. Jacinto, Yb31/Tm31 co-doped NaNbO3 nanocrystals as three-photon-excited luminescent nanothermometers, Sens. Actuat. B Chem. 213 (2015) 65
71. [71] P. Du, L. Luo, J.S. Yu, Controlled synthesis and upconversion luminescence of Tm31doped NaYbF4 nanoparticles for non-invasion optical thermometry, J. Alloy. Compd. 739 (2018) 926
933. [72] E.C. Ximendes, U. Rocha, T.O. Sales, N. Ferna´ndez, F. Sanz-Rodrı´guez, I.R. Martı´n, et al., In vivo subcutaneous thermal video recording by supersensitive infrared nanothermometers, Adv. Funct. Mater. 27 (2017) 1702249.

270

Handbook of Nanomaterials in Analytical Chemistry

[73] S. Zheng, W. Chen, D. Tan, J. Zhou, Q. Guo, W. Jiang, et al., Lanthanide-doped NaGdF4 core-shell nanoparticles for non-contact self-referencing temperature sensors, Nanoscale 6 (2014) 5675
5679. [74] L. Marciniak, A. Bednarkiewicz, Nanocrystalline NIR-to-NIR luminescent thermometer based on Cr31,Yb31 emission, Sens. Actuat. B Chem. 243 (2017) 388
393. [75] L. Marciniak, K. Trejgis, Luminescence lifetime thermometry with Mn31
Mn41 codoped nanocrystals, J. Mater. Chem. C 6 (2018) 7092
7100. [76] J. Drabik, B. Cichy, L. Marciniak, New type of nanocrystalline luminescent thermometers based on Ti31/Ti41 and Ti41/Ln31 (Ln31 5 Nd31, Eu31, Dy31) luminescence intensity ratio, J. Phys. Chem. C 122 (2018) 14928
14936. [77] A. Bednarkiewicz, K. Trejgis, J. Drabik, A. Kowalczyk, L. Marciniak, Phosphorassisted temperature sensing and imaging using resonant and nonresonant photoexcitation scheme, ACS Appl. Mater. Interfaces 9 (2017) 43081
43089. [78] K. Trejgis, L. Marciniak, The influence of manganese concentration on the sensitivity of bandshape and lifetime luminescent thermometers based on Y3Al5O12:Mn31,Mn41, Nd31 nanocrystals, Phys. Chem. Chem. Phys. 20 (2018) 9574
9581. [79] K. Kniec, L. Marciniak, The influence of grain size and vanadium concentration on the spectroscopic properties of YAG:V31,V51and YAG:V, Ln31(Ln31 5 Eu31, Dy31, Nd31) nanocrystalline luminescent thermometers, Sens. Actuat. B Chem. 264 (2018) 382
390. [80] K. Elzbieciak, A. Bednarkiewicz, L. Marciniak, Temperature sensitivity modulation through crystal field engineering in Ga31 co-doped Gd3Al5-xGaxO12:Cr31, Nd31 nanothermometers, Sens. Actuat. B Chem. 269 (2018) 96
102. [81] H. Kusama, O.J. Sovers, T. Yoshioka, Line shift method for phosphorus temperature measurements, Jpn. J. Appl. Phys. 15 (1976) 2349
2358. [82] M. Quintanilla, A. Benayas, R. Naccache, F. Vetrone, Luminescent nanothermometry with lanthanide-doped nanoparticles, in: Luı´s Dias Carlos, Fernando Palacio (Eds.), Thermom. Nanoscale Tech. Sel. Appl., The Royal Society of Chemistry, 2015, pp. 124
166. [83] U. Rocha, C. Jacinto Da Silva, W. Ferreira Silva, I. Guedes, A. Benayas, L. Martı´nez Maestro, et al., Subtissue thermal sensing based on neodymium-doped LaF3 nanoparticles, ACS Nano. 7 (2013) 1188
1199. [84] H. Peng, H. Song, B. Chen, J. Wang, S. Lu, X. Kong, et al., Temperature dependence of luminescent spectra and dynamics in nanocrystalline Y2O3:Eu31, J. Chem. Phys. 118 (2003) 3277
3282. ´ ˇ Anti´c, S. Culubrk, [85] M.G. Nikoli´c, Z. J.M. Nedeljkovi´c, M.D. Drami´canin, Temperature sensing with Eu31 doped TiO2 nanoparticles, Sens. Actuat. B Chem. 201 (2014) 46
50. [86] O.A. Savchuk, P. Haro-Gonza´lez, J.J. Carvajal, D. Jaque, J. Massons, M. Aguilo´, et al., Er:Yb:NaY2F5O up-converting nanoparticles for sub-tissue fluorescence lifetime thermal sensing, Nanoscale 6 (2014) 9727
9733. [87] A. Siaı¨, P. Haro-Gonza´lez, K. Horchani-Naifer, M. Fe´rid, La2O3: Tm, Yb, Er upconverting nano-oxides for sub-tissue lifetime thermal sensing, Sens. Actuat. B Chem. 234 (2016) 541
548. [88] L. Garcı´a-Rodrı´guez, L. de Sousa-Vieira, M.A. Herna´ndez-Rodriguez, A.D. LozanoGorrı´n, V. Lavı´n, U.R. Rodrı´guez-Mendoza, et al., Nanoperovskite doped with Yb31 and Tm31 ions used as an optical upconversion temperature sensor, Opt. Mater. 83 (2018) 187
191.

Pressure and temperature optical sensors

271

[89] M. Kumar Mahata, T. Koppe, K. Kumar, H. Hofs¨ass, U. Vetter, Demonstration of temperature dependent energy migration in dual-mode YVO4: Ho31/Yb31 nanocrystals for low temperature thermometry, Sci. Rep. 6 (2016) 36342
36352. [90] S. Zhou, S. Jiang, X. Wei, Y. Chen, C. Duan, M. Yin, Optical thermometry based on upconversion luminescence in Yb31/Ho31 co-doped NaLuF4, J. Alloy. Compd. 588 (2014) 654
657. [91] W. Xu, H. Zhao, Y. Li, L. Zheng, Z. Zhang, W. Cao, Optical temperature sensing through the upconversion luminescence from Ho31/Yb31codoped CaWO4, Sens. Actuat. B 188 (2013) 1096
1100. [92] V. Lojpur, M. Nikolic, L. Mancic, O. Milosevic, M.D. Dramicanin, Y2O3:Yb,Tm and Y2O3:Yb,Ho powders for low-temperature thermometry based on up-conversion fluorescence, Ceram. Int 39 (2013) 1129
1134. [93] E. Corte´s-Adasme, M. Vega, I.R. Martin, J. Llanos, Synthesis and characterization of SrSnO3 doped with Er31for up-conversion luminescence temperature sensors, RSC Adv. 7 (2017) 46796
46802. [94] D. Manzani, J.F. da S. Petruci, K. Nigoghossian, A.A. Cardoso, S.J.L. Ribeiro, A portable luminescent thermometer based on green up-conversion emission of Er31/ Yb31 co-doped tellurite glass, Sci. Rep. 7 (2017) 41596. [95] V. Kumar, S. Som, S. Dutta, S. Das, H.C. Swart, Influence of Ho31 doping on the temperature sensing behavior of Er31
Yb31 doped La2CaZnO5 phosphor, RSC Adv. 6 (2016) 84914
84925. [96] M. Seaver, J.R. Peele, Noncontact fluorescence thermometry of acoustically levitated waterdrops, Appl. Opt. 29 (1990) 4956. [97] X. Wang, X. Song, C. He, C.J. Yang, G. Chen, X. Chen, Preparation of reversible colorimetric temperature nanosensors and their application in quantitative twodimensional thermo-imaging, Anal. Chem. 83 (2011) 2434
2437. [98] C.D.S. Brites, P.P. Lima, N.J.O. Silva, A. Milla´n, V.S. Amaral, F. Palacio, et al., A luminescent molecular thermometer for long-term absolute temperature measurements at the nanoscale, Adv. Mater. 22 (2010) 4499
4504. [99] T. Barilero, T. Le Saux, C. Gosse, L. Jullien, Fluorescent thermometers for dualemission-wavelength measurements: molecular engineering and application to thermal imaging in a microsystem, Anal. Chem. 81 (2009) 7988
8000. [100] C. Baleiza˜o, S. Nagl, S.M. Borisov, M. Sch¨aferling, O.S. Wolfbeis, M.N. BerberanSantos, An optical thermometer based on the delayed fluorescence of C70, Chem. Eur. J. 13 (2007) 3643
3651. [101] V.A. Vlaskin, N. Janssen, J. van Rijssel, R. Beaulac, D.R. Gamelin, Tunable dual emission in doped semiconductor nanocrystals, Nano Lett. 10 (2010) 3670
3674. [102] A.E. Albers, E.M. Chan, P.M. McBride, C.M. Ajo-Franklin, B.E. Cohen, B.A. Helms, Dual-emitting quantum dot/quantum rod-based nanothermometers with enhanced response and sensitivity in live cells, J. Am. Chem. Soc. 134 (2012) 9565
9568. [103] W.J. Kennedy, K.A. Slinker, B.L. Volk, H. Koerner, T.J. Godar, G.J. Ehlert, et al., High-resolution mapping of thermal history in polymer nanocomposites: gold nanorods as microscale temperature sensors, ACS Appl. Mater. Interfaces 7 (2015) 27624
27631. [104] M.A. Herna´ndez-Rodrı´guez, M.M. Afonso, J.A. Palenzuela, I.R. Martı´n, K. SolerCarracedo, Carbon dots as temperature nanosensors in the physiological range, J. Lumin. 196 (2018) 313
315.

272

Handbook of Nanomaterials in Analytical Chemistry

[105] J. Ruiz-Fuertes, O. Gomis, S.F. Leo´n-Luis, N. Schrodt, F.J. Manjo´n, S. Ray, et al., Pressure-induced amorphization of YVO4:Eu31 nanoboxes, Nanotechnology 27 (2016) 025701. [106] J. Wang, Q. Cui, T. Hu, J. Yang, X. Li, Y. Liu, et al., Pressure-induced amorphization in BaF2 nanoparticles, J. Phys. Chem. C. 120 (2016) 12249
12253. [107] T. Tro¨ster, Optical studies of non-metallic compounds under pressure, in: K.A. Gschneidner, J.-C.G. Bu¨nzli, V.K. Pecharsky (Eds.), Handb. Phys. Chem. Rare Earths, vol. 33, North-Holland, 2003, pp. 515
589. [108] K.L. Bray, M. Glasbeek, H. Kunkely, A. Vogler, in: H. Yersin (Ed.), Transition Metal and Rare Earth Compounds Excited States, Transitions, Interactions I, Springer, New York, 2001. [109] J.D. Barnett, S. Block, G.J. Piermarini, An optical fluorescence system for quantitative pressure measurement in the diamond-anvil cell, Rev. Sci. Instrum. 44 (1973) 1
9. [110] R.A. Forman, G.J. Piermarini, J.D. Barnett, S. Block, Pressure measurement made by the utilization of ruby sharp-line luminescence, Science 176 (1972) 284
285. [111] H.K. Mao, J. Xu, P.M. Bell, Calibration of the ruby pressure gauge to 800 kbar under quasi-hydrostatic conditions, J. Geophys. Res. 91 (1986) 4673
4676. [112] A. Dewaele, M. Torrent, P. Loubeyre, M. Mezouar, Compression curves of transition metals in the Mbar range: experiments and projector augmented-wave calculations, Phys. Rev. B. 78 (2008) 104102. [113] F. Datchi, A. Dewaele, P. Loubeyre, R. Letoullec, Y. Le Godec, B. Canny, Optical pressure sensors for high-pressure
high-temperature studies in a diamond anvil cell, High Press. Res. 27 (2007) 447
463. [114] F. Datchi, R. LeToullec, P. Loubeyre, Improved calibration of the SrB4O7:Sm21 optical pressure gauge: advantages at very high pressures and high temperatures, J. Appl. Phys. 81 (1997) 3333
3339. [115] M. Runowski, P. Wo´zny, N. Stopikowska, Q. Guo, S. Lis, Optical pressure sensor based on the emission and excitation band width (FWHM) and luminescence shift of Ce31 doped fluorapatite
high-pressure sensing, ACS Appl. Mater. Interfaces 11 (2019) 4131
4138. [116] H. Arashi, M. Ishigame, Diamond anvil pressure cell and pressure sensor for hightemperature use, Jpn. J. Appl. Phys. 21 (1982) 1647
1649. [117] P.R. Wamsley, K.L. Bray, High pressure optical studies of doped YAG, J. Lumin. 6061 (1994) 188
191. [118] M.A. Herna´ndez-Rodrı´guez, J.E. Mun˜oz-Santiuste, V. Lavı´n, A.D. Lozano-Gorrı´n, P. Rodrı´guez-Herna´ndez, A. Mun˜oz, et al., High pressure luminescence of Nd31 in YAlO3 perovskite nanocrystals: a crystal-field analysis, J. Chem. Phys. 148 (2018) 044201. [119] S. Kobyakov, A. Kami´nska, A. Suchocki, D. Galanciak, M. Malinowski, Nd31-doped yttrium aluminum garnet crystal as a near-infrared pressure sensor for diamond anvil cells, Appl. Phys. Lett. 88 (2006) 234102. [120] Y.R. Shen, W.B. Holzapfel, Effect of pressure on energy levels of Sm21 in BaFCl and SrFCl, Phys. Rev. B 51 (1995) 15752
15762. [121] B. Lorenz, Y.R. Shen, W.B. Holzapfel, Characterization of the new luminescence pressure sensor SrFCl:Sm21, High Press. Res. 12 (1994) 91
99. [122] R. Stefani, A.D. Maia, E.E.S. Teotonio, M.A.F. Monteiro, M.C.F.C. Felinto, H.F. Brito, Photoluminescent behavior of SrB4O7:RE21 (RE 5 Sm and Eu) prepared by Pechini, combustion and ceramic methods, J. Solid State Chem. 179 (2006) 1086
1092.

Pressure and temperature optical sensors

273

[123] P. Wo´zny, M. Runowski, S. Lis, Influence of boric acid/Sr21 ratio on the structure and luminescence properties (colour tuning) of nano-sized, complex strontium borates doped with Sm21 and Sm31 ions, Opt. Mater. 83 (2018) 245
251. [124] J.M. Leger, C. Chateau, A. Lacam, SrB4O7:Sm21 pressure optical sensor: investigations in the megabar range, J. Appl. Phys. 68 (1990) 2351
2354. [125] S.V. Rashchenko, A. Kurnosov, L. Dubrovinsky, K.D. Litasov, Revised calibration of the Sm:SrB4O7 pressure sensor using the Sm-doped yttrium-aluminum garnet primary pressure scale, J. Appl. Phys. 117 (2015) 2
7. [126] Q. Jing, Q. Wu, L. Liu, J. Xu, Y. Bi, Y. Liu, et al., An experimental study on SrB4O7: Sm21 as a pressure sensor, J. Appl. Phys. 113 (2013) 023507. [127] H. Yuan, K. Wang, S. Li, X. Tan, Q. Li, T. Yan, et al., Direct zircon-to-scheelite structural transformation in YPO4 and YPO4:Eu31 nanoparticles under high pressure, J. Phys. Chem. C 116 (2012) 24837
24844. [128] M. Behrendt, S. Mahlik, K. Szczodrowski, B. Kukli´nski, M. Grinberg, Spectroscopic properties and location of the Tb31 and Eu31 energy levels in Y2O2S under high hydrostatic pressure, Phys. Chem. Chem. Phys. 18 (2016) 22266
22275. [129] N.J. Hess, G.J. Exarhos, Temperature and pressure dependence of laser induced fluorescence in Sm:YAG—a new pressure calibrant, High Press. Res. 2 (1989) 57
64. [130] K. Dziubek, M. Citroni, S. Fanetti, A.B. Cairns, R. Bini, High-pressure high-temperature structural properties of urea, J. Phys. Chem. C 121 (2017) 2380
2387.

Nanoparticle-integrated electrochemical devices for identification of mycotoxins

11

Suresh Kumar Kailasa1, Tae Jung Park2, Rakesh Kumar Singhal3 and Hirakendu Basu3 1 Department of Applied Chemistry, S. V. National Institute of Technology, Surat, India, 2 Department of Chemistry, Institute of Interdisciplinary Convergence Research, Research Institute of Halal Industrialization Technology, Chung-Ang University, 84 Heukseok-ro, Dongjak-Gu, Seoul, Republic of Korea, 3Analytical Chemistry Division, Bhabha Atomic Research Center, Trombay, Mumbai, India

11.1

Introduction

Mycotoxins have been considered as secondary metabolites of fungal species that cause severe toxic effect on human beings and animals. Generally, mycotoxins have shown several toxicological effects including teratogenic, carcinogenic, mutagenic, hepatotoxic, hemorrhagic, estrogenic, dermatoxic, nephrotoxic, immunotoxic, and neurotoxic [1
3]. So far, 300
400 mycotoxins have been found in various fungal species, some of them are aflatoxins, ochratoxin, zearalenone, patulin, citrinin, trichothecenes, and deoxynivalinol. Generally, aflatoxins are produced by Aspergillus parasiticus and Aspergillus flavus species and exhibited high carcinogenic effects to various living organism via aflatoxicosis [4]. Importantly, permissible limit for aflatoxin B1 (AFB1) is 2 ppm in rice and corn, whereas 4 ppm for total aflatoxins [5]. Similarly, the maximum permissible limit for AFB1 is 8 ppm in walnuts, pistachios, almonds, and apricot kernels, whereas 10 ppm for total aflatoxins [5]. In recent years, nanomaterials have been integrated with various analytical tools for the development of efficient analytical strategies for assaying of various molecules because of their unique properties [6
11]. Further, nanostructured materials have been successfully used as sorbents in various sample preparations for the extraction and preconcentration of various chemical species prior to their identification by various analytical instruments [12]. To support this, nanomaterials have proven to be the promising and attractive materials in developing electrochemical sensors for the recognition of various chemical species. These nanomaterials were used as transducers for the immobilization of various chemical species on the surfaces of electrodes. As a result, the analytical performance of electrodes was greatly

Handbook of Nanomaterials in Analytical Chemistry. DOI: https://doi.org/10.1016/B978-0-12-816699-4.00011-6 Copyright © 2020 Elsevier Inc. All rights reserved.

276

Handbook of Nanomaterials in Analytical Chemistry

improved for the identification and quantification of various chemical species by electroanalytical techniques. Generally, the identification and quantification of mycotoxins have been carried out at centralized laboratories using various sophisticated analytical instruments. Various analytical instruments, such as high-performance liquid chromatography (HPLC), fluorescence, enzyme-linked immunosorbent assay, chemiluminescence, gas chromatography (GC), capillary electrophoresis, quartz crystal microbalance, and chromatography coupled with mass-spectrometric techniques, have been used for assaying of mycotoxins in various food samples. Even though these analytical techniques have found to be sensitive, unfortunately these are not suitable for onsite recognition and quantification of mycotoxins because of their instrumentations’ size. Importantly, these are expensive, and required skilled persons for the instruments operations and sample preparations. Point-of-care assays of various chemical species are emerging for medical biology, agricultural products, and environmental monitoring. Recently, nanostructural composites have been integrated with electrochemical devices for the selective and sensitive detection of mycotoxins in various food samples. Several review articles have successfully illustrated the use of nanomaterialintegrated analytical techniques for the detection and quantification of mycotoxins in various samples [13
15]. Further, few review papers have described the potential use of nanomaterials in the development of electrochemical sensors for the detection of mycotoxins [16
19]. In this chapter, we briefly summarize the promising applications of functional nanomaterials in electrochemical techniques for assaying of mycotoxins in various sample matrices. Finally, it describes the use of functional nanomaterials [carbon nanomaterials, metal and metal oxide nanoparticles (NPs)] in electrochemical analytical techniques for the detection of mycotoxins in various food samples.

11.2

Surface modification of electrodes for electrochemical sensing of mycotoxins

11.2.1 Modification of electrodes with carbon nanomaterials Recently, carbon nanomaterials [graphene (G), graphene oxide (GO), single-walled carbon nanotubes (SWCNTs), and multiwalled carbon nanotubes (MWCNTs)] have been utilized as potential candidates in various fields of sciences including biomedical, analytical sciences, and energy devices because of their tremendous properties (e.g., high surface area, good electrical conductivity, nontoxicity, high mechanical strength, and chemical stability) [20
22]. Thus, carbon nanomaterials have received significant interest and progress in developing electrochemical sensors for assaying of various analytes [23,24]. The mobility of electrons, biocompatibility, and electrical resistance of carbon nanomaterials have tremendously improved by modifying their surfaces with various organic and inorganic biomolecules, which tune their sensing applications selectively toward specific molecules. For example, aflatoxin oxidase was conjugated with MWCNTs and then coated on the surfaces

Nanoparticle-integrated electrochemical devices for identification of mycotoxins

277

of Pt electrode for biosensing of AFB1 [25]. The researchers evaluated the analytical performance of the developed biosensor and found that the analytical data are equal to sophisticated analytical techniques such as chromatography and mass spectrometry (MS). Owing to the large surface area of the MWCNT, large amount of aflatoxin oxidase was effectively coated on the surfaces of MWCNTs, favoring for selective capturing of AFB1. Similarly, sterigmatocystin was successfully detected by using electrochemical sensor with the modification of electrodes with MWCNTs
aflatoxin
detoxifizyme [26]. This developed electrochemical sensor exhibited good linearity in the range of 4.29
0.13 μM with detection limit of 0.13 μM. Further, SWCNTs and MWCNTs were incorporated into chitosan to generate nanostructured film onto indium
tin
oxide (ITO) for the conjugation of rabbit-immunoglobulin and bovine serum albumin (BSA) to identify ochratoxin-A (OTA) [27]. The authors noticed that the electro-active surface area of modified electrodes was greatly improved, which results to enhance sensing ability of electrochemical sensor toward OTA with low detection limit as 0.25 ng dL21. The monoclonal anti-AFB1 was covalently attached onto the surfaces of COOHMWCNTs-ITO via N-ethyl-N0 -(3-dimethylaminopropyl)-carbodiimide (EDC)
Nhydroxysuccinimide (NHS) chemistry. The carboxylated MWCNTs were coated onto ITO glass and then functionalized with monoclonal AFB1 antibodies for sensing of AFB1 using electrochemical technique [28]. Fig. 11.1 shows the schematic

Figure 11.1 Design of ITO glass electrodes with MWCNTs-antibody-AFB1 for electrochemical sensing of AFB1. Source: Reprinted with permission from C. Singh, S. Srivastava, M.A. Ali, T.K. Gupta, G. Sumana, A. Srivastava, et al., Carboxylated multiwalled carbon nanotubes based biosensor for aflatoxin detection, Sens. Actuat. B 185 (2013) 258
264, with permission.

278

Handbook of Nanomaterials in Analytical Chemistry

representation for the modification of ITO glass electrodes with MWCNTsantibody-AFB1 for the electrochemical sensing of AFB1. This method was able to detect AFB1 even at 0.08 ng mL21. The researchers noticed that the well-defined redox peaks are generated due to the redox reaction of [Fe(CN)6]32/42 in the presence of MWCNTs/ITO electrode (Fig. 11.2A). The magnitude of current of antiAFB1/MWCNTs/ITO decreases due to the insulating nature of antibodies. These electrochemical responses revealed the surface modification of MWCNTS/ITO

(A) 6.0××10–4 (a) (b) (c)

Current (A)

3.0×10–4

0.0 (a) c-MWCNTs/ITO (b) Anti-AFB1/MWCNTs/ITO

–3.0×10–4

(c) BSA/Anti-AFB1/MWCNTs/ITO

–0.4

–0.2

0.0

0.2

0.4

0.6

0.8

1.0

Potential (V; vs Ag/AgCl)

(C)

2.7×10–4

4.0×10–4

1.0×10–4

2.6×10–4

2.0×10–4

2.5×10–4

2.4×10–4 0.2 0.4 0.6 0.8 1.0 1.2 1.4 –1

Concentration (ng mL )

0.0

1.375 ng mL–1 –1

1.125 ng mL 0.875 ng mL–1 0.675 ng mL–1

–1.0×10–4

Current (A)

Current (A)

2.0×10–4

Current (A)

3.0×10–4

3.7×10–4

0.0

3.6×10–4

Current (A)

(B)

–2.0×10–4

–1

0.375 ng mL 0.25 ng mL–1

–2.0×10–4 –0.6

–0.4

–0.2

0.0

0.2

Potential (V)

0.4

0.6

3.5×10–4

3.4×10–4

3.3×10–4

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6

–4.0×10–4 –0.4

–1

Concentration (ng mL )

–0.2

0.0

0.2

0.4

0.6

0.8

Potential (V)

Figure 11.2 (A) Characterization of c-MWCNTs/ITO (curve a), anti-AFB1/MWCNTs/ITO (curve b), and BSA/anti-AFB1/MWCNTs/ITO (curve c) by cyclic voltammetric (CV) in the presence of 5 mM [Fe(CN)6]32/42, (B) CV responses of BSA/anti-AFB1/MWCNTs/ITO at various concentrations of AFB1 in the presence of 5 mM [Fe(CN)6]32/42; calibration graph between the oxidation peak current and concentration of AFB1 (inset of B), (C) control experiment of c-MWCNTs/ITO as a function of AFB1; inset is oxidation peak current vs AFB1 concentration plot of c-MWCNTs/ITO electrode. Source: Reprinted with permission from C. Singh, S. Srivastava, M.A. Ali, T.K. Gupta, G. Sumana, A. Srivastava, et al., Carboxylated multiwalled carbon nanotubes based biosensor for aflatoxin detection, Sens. Actuat. B 185 (2013) 258
264.

Nanoparticle-integrated electrochemical devices for identification of mycotoxins

279

electrode with antibody. The response of BSA/anti-AFB1/MWCNTs/ITO bioelectrode was investigated as a function of AFB1 concentration using cyclic voltammetric (CV) (Fig. 11.2B). It clearly shows that the response current for BSA/ anti-AFB1/MWCNTs/ITO electrode was progressively increased with increasing AFB1 concentration, confirming the formation of antigen
antibody complex between AFB1 and anti-AFB1-MWCNTs/ITO electrode surface. Fig. 11.2C represents the control experiment using the c-MWCNTs/ITO electrode as a function of AFB1 concentration conducted in PBS-containing 5 mM [Fe(CN)6]32/42. The response current obtained for c-MWCNTs/ITO does not significantly change as a function of AFB1 concentration. Similarly, a simple electrochemical sensor was fabricated for sensing of Clostridium difficile toxin B (Tcd B) [29]. In this method, authors modified the electrode with MWCNTs for immunosensing of Tcd B. The fabricated immunosensor exhibited good selectivity and achieved lower detection limit of 0.7 pg mL21. Further, SWCNTs and microcystin (MC)-leucine-arginine (LR) antibodies were coated onto the surfaces of electrode for electrochemical sensing of MC-LR [30]. The developed sensor has proven to be a facile and sensitive platform for assaying of MC-LR at 0.6 ng mL21. A facile electrochemical immunosensor analytical strategy was established for the detection of MC-LR using singlewalled carbon nanohorn (SWNH)-modified electrode [31]. The developed method was successfully applied to detect MC-LR in food and environmental samples with good precision and accuracy. The monoclonal antibody was covalently attached with poly(3,4-ethylenedioxythiophene) coated on Nafion-supported MWCNTs on a glassy carbon electrode (GCE) for electrochemical sensing of cholera toxin (CT) [32]. CT was detected via “sandwich-type” assay and achieved limit of detection was 1.0 fg mL21. The electrochemical device was designed with novel plastic antibody and then coated on carbon nanotubes for assaying of MC-LR [33]. In this work, authors decorated carbon electrodes with molecularly imprinted MWCNTs for the detection of MC-LR, MC-YR, and MC-RR, thereby sensor was able to detect mycotoxin even at 1.0 ng mL21 without any interference. The SWCNTs-chitosan (CS) nanocomposites were coated on GCE and then modified with anti-rabbit immunoglobulin G secondary antibody for immunosensing of fumonisin B1 (FB1) in corn [34]. This method exhibited good selectivity and specificity for the detection of FB1 and allowed to detect FB1 even at 2 pg mL21, which is much lower than the European Union legislation (i.e., 2
4 mg L21). Similarly, the MWCNTs-chitosan nanocomposite surfaces were activated by EDC and NHS chemistry for effective attachment of AFB1-BSA antigen on the surfaces of electrode [35]. The researchers generated a catalytic signal by enzymatic reaction of horseradish peroxidase (HRP) in the presence of H2O2 and 3,30 ,5,50 tetramethylbenzidine. As a result, the developed immunosensor exhibited wider linearity in the range of 0.0001
10 ng mL21, and achieved detection limit of 0.1 pg mL21. This method was successfully applied to detect AFB1 in various food samples (corn kernels and soy beans). Furthermore, polyclonal anti-AFB1 antibody was attached on the surfaces of mesoporous carbon (MSC) nanomaterials and then coated on the surfaces of electrode for rapid detection of AFB1 in food samples [36].

280

Handbook of Nanomaterials in Analytical Chemistry

The detection mechanism was based on the specific antigen
antibody reaction and showed good electrochemical responses for sensing of AFB1 as low as 3.0 pg mL21 without aid of any extraction technique. Recently, carbon nanomaterial-based electrochemical methods have proven to be facile and inexpensive analytical tools for the discriminative sensing and quantification of trace chemical species at minimal volume of samples [36]. The above methods revealed that carbon nanostructured materials have been successfully integrated with various electroanalytical techniques for the detection of trace level mycotoxins because of their high surface area, cylindrical symmetry, quasi-1D nature, and sp2 hybridization of carbon bonds, respectively. These specific properties allow them to act as promising electrochemical materials for the fabrication of nanoarchitectured electrochemical sensors [37,38]. The analytical performance of electrochemical devices could be greatly enhanced by the modification of electrodes with functionalized carbon nanostructured materials, which improves the binding ability of electrodes toward mycotoxins and the sensitivity. Graphene is considered as a 2D nanosheet, and exhibits larger surface area and higher electrical conductivity and thermal properties than those of carbon nanotubes. In last few decades, graphene and its derivatives [e.g., GO and reduced GO (rGO)] have received tremendous interest in various fields of science [39]. Apart from their potential uses in various applications, graphene-based nanomaterials have been successfully integrated with electrochemical devices for the detection of wide variety of molecules. Further, graphene-coated electrodes acted as potential sensors for the detection of various chemical species including organic and inorganic biomolecules [40,41]. Graphene and its derivatives have been coated onto the surfaces of electrodes for electrochemical sensing of mycotoxins in various samples. For example, rapid Fourier transformation cyclic voltammetry was developed for the detection of OTA by modifying a GCE with rGO
Au NPs-ionic liquid (1butyl-3-methylimidazolium tetra fluoroborate) [42]. These modified electrodes exhibited several features such as rapid response time (,7 s), lower detection limit (2.2 3 10210 M), and high stability (B60 days). Graphene nanosheets (GNS) were modified with phenyl and aminophenyl (PhPhNH2/GCE) and then coated onto the electrode surfaces (GNS/Ph-PhNH2/GCE) [43]. Various analytical techniques such as field-emission scanning electron microscopy, atomic force microscopy, X-ray diffraction, electrochemical impedance spectroscopy (EIS), and CV techniques were used for the characterization of modified electrodes. In this work, authors modified electrode with rabbit anti-mouse IgG
alkaline phosphatase (RαMIgG-ALP)-Au NPs. The modified electrode was effectively captured with rabbit clostridium butyricum botulinum neurotoxin type E (BoNT/E) via EDC-NHS chemistry. This method was able to detect BoNT/E in 1 h 5.0 min. The rGO was coated onto the surfaces of ITO-glass substrate by electrophoretic deposition technique and then modified with the monoclonal antibodies of AFB1 for electrochemical sensing of AFB1 [44]. This method exhibited high sensitivity (68 μA ng21 mL cm22) and achieved lower detection limit of 0.12 ng mL21. The GO was synthesized by modifying Hummers method and coated onto the

Nanoparticle-integrated electrochemical devices for identification of mycotoxins

281

Au electrode [45]. The monoclonal antibody (anti-AFB1) was immobilized onto the surfaces of GO
Au electrode through EDC-NHS chemistry for label-free electrochemical sensing of AFB1 by EIS. The authors observed that the wider linear range (0.5
5 ng mL21) with high sensitivity (639 Ω/ng21 mL), and long stability (5 weeks). An electrochemical sensor was fabricated by coating rGO films on the surfaces of electrodes for the detection of AFB1 [46]. The authors observed that an impressive detection limit of 0.1 fg mL21, which is higher sensitivity than the traditional analytical methods. The above electrochemical sensors were effectively applied to detect AFB1 in various food samples. To improve the specificity and analytical efficiency, 5,10,15,20-tetraphenyl21H,23H-porphine cobalt flat was decorated on rGO surfaces with Pt NPs (PtNPs/ CoTPP/rGO) and then modified with monoclonal rabbit anti-AFB1 antibody for electrochemical immunosensing of AFB1 in bulk peanut samples [47]. The modified electrode surfaces selectively captured AFB1 even at 5.0 pg mL21 and exhibited good accuracy and precision for assaying of AFB1 in food samples. Similarly, the surfaces of rGO were modified with polypyrrole (PPy) and pyrrolepropylic acid (PPa), where rGO improves conductivity, stability, PPy enhances film electroactivity, and PPa provides specific sites for immobilization [48]. The modified electrode acted as a promising electrochemical device for a label-free immunosensing of AFB1 with detection limit of 10 fg mL21. The modified electrode provides greater anchor sites for the capturing of AFB1, allowing to develop a portable sensor for the detection of AFB1 in food samples. Similarly, 2,5-di-(2-thienyl)-1-pyrrole-1-(pbenzoic acid) and Au NPs were functionalized with GO and then coated onto the surfaces of Au electrode for electrochemical immunosensing of AFB1 [49]. The modified immunosensor exhibited rapid electron transfer, and effective microenvironment for capturing of antibody. As a result, the developed immunosensor exhibited lower detection limit (1.0 fM) with wider dynamic range (3.2 fM
0.32 pM) and longer stability (B26 weeks). This method exhibits several analytical features such as high sensitivity, stability, and repeatability. A novel impedance spectroscopic method was developed for the rapid detection of OTA in food samples [50]. In this approach, authors immobilized anti-OTA antibody onto the poly(amidoamine) (PAMAM) dendrimer-functionalized GO nanosheets. It was noticed that instant catalyst was formed on PAMAM dendrimer-GO for rapid detection of OTA through catalytic precipitation. In this, 5 μL of OTA and 5 μL of mAb-GOPAMAM-Mn21 were casted on OTA-BSA/GCE, and then incubated for 25 min. The fabricated electrode was treated with KMnO4 solution (50 μL, 10 mM) for 1 min. The fabricated electrode was dipped into precipitation solution (5 mM 4-CN) for 25 min. The modified electrode was applied to detect OTA by EIS (Fig. 11.3). Further, the performance of EIS was investigated before and after precipitation of modified electrode (Fig. 11.4A). The authors noticed that mAb-GO-PAMAMMnO2-based electrode significantly enhanced the signal intensity up to 144.8% (curve b, Fig. 11.4A), which revealed that it has higher sensitivity than that of mAb-GO as signal label (curve d, Fig. 11.4A). Noticeably, nanocatalytic precipitation process greatly improved the sensor signal (654.2%) (curve c, Fig. 11.4A). Remarkably, the presence of MnO2-modified electrode significantly increased the

282

Handbook of Nanomaterials in Analytical Chemistry

Figure 11.3 Designing of instant protocol and the instant catalyst for the amplified impedimetric detection of OTA. Source: Reprinted from J. Tang, Y. Huang, C. Zhang, H. Liu, D. Tang, Amplified impedimetric immunosensor based on instant catalyst for sensitive determination of ochratoxin A, Biosens. Bioelectron. 86 (2016) 386
392, with permission.

resistance after introducing 4-CN (Fig. 11.4B). Moreover, no significant resistance was noticed on EIS of the GO-mAb (Fig. 11.4C), PAMAM-GO-mAb (Fig. 11.4D), and Mn21-PAMAM-GO-mAb (Fig. 11.4E). Thus, the signal amplification of the impedimetric signal was mainly due to in situ generation of MnO2 via nanocatalytic precipitation process. This detection method is based on the capturing of anti-OTAGO-PAMAM-Mn21 onto the electrode surface, inducing in situ formation of MnO2 via redox reaction between Mn21 and KMnO4. Under optimal conditions, this method exhibited a wide dynamic linear range from 0.1 pg mL21 and 30 ng mL21 with detection limit of 0.055 pg mL21. This approach was successfully applied to detect OTA in red wine samples. The analytical efficiency of immunosensors was significantly enhanced by modifying GO nanosheets with metal NPs. To this, Srivastava’s group modified the surfaces of rGO with Ni NPs and then deposited onto ITO-coated glass electrode [51]. The fabricated electrode was successfully used as immunosensor for sensitive detection of AFB1 even at 0.16 ng mL21. The developed immunosensor exhibited higher sensitivity than that of HPLC technique. Furthermore, rGO aerogel was

Figure 11.4 (A) Nyquist diagrams of (a) OTA-BSA/GCE, (b) substrate “a” reacted with OTA 1 mAb-GO-PAMAM-Mn21 and KMnO4, (c) substrate “b” reacted with 4-CN, and (d) substrate “a” reacted with mAb-GO; Nyquist diagrams of (B) mAb-GO-PAMAM-MnO2/OTA-BSA/ GCE, (C) mAb-GO/OTA-BSA/GCE, (D) mAb-GO-PAMAM/OTA-BSA/GCE, and (E) mAb-GO-PAMAM-Mn21/OTA-BSA/GCE with 10 mM Fe (CN)642/32 in the presence of 0.1 M KCl (solid: background current; hollow: after reaction with 4-CN). Source: Reprinted from J. Tang, Y. Huang, C. Zhang, H. Liu, D. Tang, Amplified impedimetric immunosensor based on instant catalyst for sensitive determination of ochratoxin A, Biosens. Bioelectron. 86 (2016) 386
392, with permission.

284

Handbook of Nanomaterials in Analytical Chemistry

labeled with a single-stranded DNA (ss-HSDNA/rGOae) and then decorated on rotating disk electrode for impedimetric biosensing of AFB1 [52]. The authors studied the CV responses from ss-HSDNA/rGOae electrode at three different redox 42 mediators (i.e., neutral FcCH2OH, cationic RuðNH3 Þ31 6 , and anionic FeðCNÞ6 ) and noticed that neutral FcCH2OH has shown strong affinity toward electrode surface through π 2 π interactions between cyclopentadienyl ring of FcCH2OH and aromatic rings of ss-HSDNA/rGOae electrode. As a result, the authors achieved an impressive detection limit of 0.04 ng mL21 with a linear range of 1 3 10210 to 7 3 1028 g mL21. Recently, the GCE was modified with spherical Au NPs and then decorated with poly (3,4-ethylenedioxythiophene) and GO nanocomposites for fast and sensitive electrochemical detection of AFB1 in maize samples [53]. The immunoassay was completed within 8 min, and the limit of detection and the limit of quantification were 0.109 and 0.377 ng mL21, respectively. The developed immunosensor exhibited good selectivity and reproducibility (92.25% and 95.79%) for the detection of AFB1 in maize samples. Similarly, a rapid and ultrafast electrochemiluminescent immunoassay exhibited good selectivity and reproducibility for the detection of aflatoxins M1 (ATM1) in milk [54]. In this approach, authors used magnetic Fe3O4-GOs as the absorbent and antibody-labeled CdTe quantum dots (QDs) as the signal tag. This method was successfully applied to detect ATM1 in milk samples with good reproducibility and repeatability. These studies suggest that the modification of electrode surfaces with carbon nanostructures (SWCNTs, MWCNTs, GO, rGO, and their derivatives) has shown tremendous improvement in analytical performance of electrochemical devices for the detection of mycotoxins in real samples with high selectivity and sensitivity. Importantly, the performance of nanomaterial-based electrochemical sensors is almost equal to sophisticated analytical techniques such as HPLC, GC-MS, and LC-MS.

11.2.2 Modification of electrodes with metal nanoparticles Metal NPs have been proven to be potential materials for the modification of electrodes for electrochemical sensing of various chemical species because of their unique properties [55]. It is well known that the surfaces of electrodes were effectively modified with various noble metal (Au, Ag, Pt, Pd, and Cu) NPs for sensitive and selective electrochemical sensing of wide variety of chemicals and biochemical molecules in various sample matrices [56]. Further, metal NPs act as promising media for electrontransfer reactions with high degree, allowing them to use as promising materials in the development of electrochemical devices for assaying of various chemical species [57
59]. As a result, metal NPs were decorated onto the surfaces of electrodes for electrochemical sensing of mycotoxins in various food samples.

11.2.2.1 Modification of electrodes based on adsorption mechanism The modification of electrode surface plays a key role in establishing sensitive electrochemical sensors for the detection of mycotoxins with reduced time and

Nanoparticle-integrated electrochemical devices for identification of mycotoxins

285

sensitivity [55]. For example, the working electrode surfaces were decorated with OTA-BSA-Au NPs through physical adsorption for electrochemical sensing of OTA in various samples [60,61]. The authors modified screen-printed electrodes with OTA-BSA or OTA-BSA-Au NPs for electrochemical detection of OTA by differential-pulse voltammetry (DPV) [60,61]. The developed method was successfully applied to detect OTA in a certified wheat standard and a noncontaminated wheat samples and exhibited good recoveries in the range of 104% 6 0.07%
107% 6 0.08%. Similarly, anti-AFB1 was decorated on electrode via selfassembled monolayers (SAM) and used as electrochemical sensor for detection of AFB1 in Brazilian nuts [62]. The developed sensor exhibited wide linear range (3.2 3 10213
3.2 3 1029 M) with lower detection limit when thiourea was used for the formation of SAM. The use of proteins was explored in fabricating electrochemical devices for the detection of AFB1 with high selectivity and sensitivity [63]. The authors observed an impressive detection limit of 6 3 10212 M. Castillo’s group described the potential application of modified electrodes in CV and EIS techniques for the detection of AFB1 [64]. In this work, the authors used K[Fe (CN)6]23/24 as redox indicators for acquiring the signal response. Poly(amidoamine) dendrimers (PAMAM G4) were immobilized on gold (Au) electrode and then attached with single-stranded amino-modified DNA aptamers for specific interaction with AFB1. The developed method was successfully applied to detect AFB1 in certified contaminated peanuts extract and spiked samples of peanuts
corn snacks. Recently, octahedral Au NPs (Oct Au NPs) were integrated with square-wave voltammetric technique for ultrasensitive electrochemical immunosensing of OTA [65]. Fig. 11.5 shows the surface modification of electrode surfaces with alumina powder, Oct Au NPs, and antibody of OTA. The authors observed that electron-transfer ability was greatly improved with the use of Oct Au NPs on the surfaces of electrode. In this approach, the authors polished GCE surfaces with alumina powder to generate mirrorlike surface and then Oct Au NPs were deposited onto GCE surface, which was further decorated with antibody of OTA. As a result, the designed immunosensor exhibited wider linear range (0.1 pg mL21
10 ng mL21) and achieved remarkable detection limit of 39 fg mL21.

11.2.2.2 Molecular assembly on metal and metal oxide nanoparticle surfaces Various organic molecules were effectively assembled on the surfaces of metal NPs and used as electrochemical sensors for the detection of wide variety of molecules [59]. It was noticed that electron-transfer reactions were greatly enhanced with the use of molecular assembly on the surfaces of metal NPs. Loyprasert’s group modified Au electrode surfaces with Ag NPs-thiourea and used as a label-free electrochemical sensor for the detection of MC-LR [66]. This method exhibited lower detection limit of 7.0 pg L21 and obtained analytical results well agreed with HPLC (p , 0.05). Moreover, the electrode was derivatized with electrochemical reduction of in situ 4-carboxyphenyl diazonium salt, which yields stable 4-carboxyphenyl monolayer [67]. The derivatized electrode was decorated with antibody of OTA for

286

Handbook of Nanomaterials in Analytical Chemistry

Figure 11.5 (A) Modification of glass carbon electrode surfaces with alumina powder, Oct Au NPs, and antibodies of OTA for electrochemical sensing of OTA (B) Steps involves in the fabrication of electrochemical sensor. Source: Reprinted from T. Zhang, B. Xing, Q. Han, Y. Lei, D. Wu, X. Ren, et al., Electrochemical immunosensor for ochratoxin A detection based on Au octahedron plasmonic colloidosomes, Anal. Chim. Acta 1032 (2018) 114
121, with permission.

detection of OTA by using CV and EIS techniques. It was noticed that the electrontransfer resistance values were gradually increased with increasing concentration of OTA (1
20 ng mL21), which allowed the detection of OTA even at 0.5 ng mL21. Liu et al. modified Au electrode with 1,6-hexanedithiol
Au colloid layer for effective loading of OTA
ovalbumin conjugate for electrochemical sensing of OTA [68]. The authors observed an impressive sensitivity with remarkable electrochemical readouts in the range of 10 pg mL21
100 ng mL21 with detection limit of 8.2 pg mL21. This method was successfully applied to detect OTA in corn samples. The same group fabricated microcomb electrode with molecular assembly of HRP and AFB1 antibody using Au NPs for electrochemical detection of AFB1 [69]. In this method, antibody
antigen complex was formed between the immobilized antiAFB1 and AFB1 via immunoreaction and then a barrier that comprised HRP and the electrode surface was introduced. The local conductivity variations were detected by HRP bioelectrocatalytic reaction. As a result, the developed immunosensor exhibited an impressive conductometric response with increasing

Nanoparticle-integrated electrochemical devices for identification of mycotoxins

287

concentration of AFB1 (0.5
10 ng mL21) with detection limit of 0.1 ng mL21. This method exhibited good precision and accuracy for the detection of AFB1 in food samples. It is well known that MC-LR causes serious problems to human health and fisheries. A label-free amperometric immunosensor was developed for the detection of MC-LR in water samples [70]. In this work, antibody was immobilized onto the surfaces of Au electrode that contains L-cysteine-modified Au NPs. The analytical performance of fabricated immunosensor was evaluated by EIS and DPV. The authors observed that the DPV current was gradually changed upon addition of MC-LR concentration (0.05
15.00 μg L21), and sensor exhibited detection limit of 20 ng L21. Similarly, Au electrode was modified with polytyramine-Au NPs and then decorated with antibodies for electrochemical sensing of MC-LR [71]. The developed sensor was very stable and achieved low detection limit of 0.01 pM. Recently, the identification and quantification of mycotoxins in various food samples have received significant attention in analytical sciences due to their toxic effects toward various living organisms. In this connection, ring-like nickel (RnNi B 10
20 nm) NPs were prepared and then deposited onto the surfaces of ITO glass substrate [72]. Then, antibody of AFB1 was immobilized onto the surfaces of ITO glass substrate for immunosensing of AFB1. This method exhibited wider linearity in the concentration range of AFB1 from 5 to 100 ng dL21 with limit of detection of 32.7 ng dL21. The prepared sensor was stable for up to 60 days and was successfully applied to detect AFB1 in real samples. Liu’s group enhanced the photoelectrochemical performance of rutile TiO2 mesocrystals by chelating assembly of polydopamine and then secondary antibodydecorated mesoporous Co3O4 nanomaterials were introduced via immunoreactions for the detection of zearalenone [73]. Similarly, samarium oxide (n-Sm2O3) nanorods were electrophoretically attached onto the surfaces of ITO glass substrate and then monoclonal antibodies of AFB1-BSA were coimmobilized for electrochemical sensing of AFB1 [74]. The prepared n-Sm2O3 nanorods were characterized by atomic force microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared, and X-ray photoelectron spectroscopic techniques. The electrochemical response of fabricated electrode was shown good linearity as a function of AFB1 concentration in the range of 10
700 pg mL21. The authors achieved remarkable limit of detection of 57.82 pg mL21 cm22 and the system exhibited sensitivity of 48.39 μA pg21 mL21 cm22. Moreover, 3-aminopropyltriethoxysilane was assembled onto the surfaces of nanoporous aluminum surfaces for covalent attachment of antibody [75]. The modified nanoporous aluminum substrate was used as electrochemical device for electrochemical sensing of ricin in food and biological samples. Vig’s group modified graphite screen-printed electrodes with Au-catalyzed deposition of silver (Ag) for impedimetric immunosensing of ATM1 [76]. This method exhibited wider linearity in the range of 15
1000 ppt with detection limit of 12 ppt. Kuang and coworkers developed aptamer-based electrochemical sensor for the identification of OTA in real samples [77]. In this approach, Au NPs were functionalized with DNA-3 and then decorated with aptamer onto the electrode surface for electrochemical sensing of OTA. The developed sensor exhibited higher sensitivity in the range of pg mL21.

288

Handbook of Nanomaterials in Analytical Chemistry

Similarly, the captured probe DNA was first attached onto the surface of Au electrode and then modified with OTA aptamer for electrochemiluminescence sensing of OTA [78]. The probe exhibited good linearity in the range of 0.05
500 pg mL21 and achieved limit of detection of 0.02 pg mL21. The fabricated biosensor was successfully applied to detect OTA in corn samples. The developed biosensor was applied to determine OTA concentration in the corn samples with satisfied results. A reliable disposable electrochemical magnetoimmunosensor was developed for the detection of OTA in coffee samples [79]. In this approach, authors initially modified carbon screen-printed electrodes with antibody-coated magnetic beads and enzyme HRP as tracer. As a result, this method exhibited remarkable detection limit of 0.32 μg L21, and successfully applied to detect OTA in coffee samples. A labelfree photoelectrochemical platform was developed for the detection of OTA using TiO2/S-BiVO4@Ag2S nanocomposites as a substrate [80]. The use of TiO2 provides high surface area and good photoelectric activity. The porous structure of S-BiVO4 is useful for in situ growth of Ag2S NPs. The authors noticed that the developed sensor exhibited lower detection limit of 1.7 pg mL21 with wide linearity in the range of 5 pg mL21
750 ng mL21. This sensor exhibited good selectivity, higher sensitivity, good accuracy, and precision. Table 11.1 summarizes the nanomaterialintegrated electrochemical analytical techniques for immunosensing of various mycotoxins. Zearalenone is a resorcyclic acid lactone, and is considered as a nonsteroidal estrogenic mycotoxin, which can be generated by fusarium fungi via polyketide pathway. A novel label-free ultrasensitive amperometric immunosensor was developed for the detection of zearalenone in clinical samples [81]. In this work, electrode surfaces were fabricated with MSC and trimetallic nanorattles (Au-AgPt). Under optimum conditions, the electrochemical sensor exhibited wide linear range (0.005
15 ng mL21) with detection limit of 1.70 pg mL21. Similarly, Feng’s group converted nanomontmorillonites into sodium montmorillonites (Na-Mont) for the immobilization of thionine, HRP, and the secondary antibody of zeranol [82]. The modified Na-Mont substrate was used as a label for immunosensing of zeranol in beef tissues. The authors noticed that the catalytic current was linearly increased with increasing concentration of zeranol (0.01
12 ng mL21), which allows the detection of zeranol even at 3 pg mL21. These observations clearly revealed that the modification of electrode surfaces with nanostructured material plays key role in selective and sensitive detection of mycotoxins with reduced sample preparations at minimal volume samples.

11.3

Summary

In this chapter, progress of nanomaterial-integrated electrochemical analytical methods for the detection of mycotoxins has been summarized. It was noticed that nanomaterial-based electrochemical techniques have been successfully applied to detect mycotoxins with high selectivity. Various nanomaterials [carbon

Table 11.1 Overview of nanomaterial-integrated electrochemical analytical techniques for the detection of mycotoxins. Surface modification of electrode

Detection technique

Linear range

Limit of detection 21

21

Analyzed mycotoxin

Reference

Aflatoxin oxidase-MWCNTs-Pt Rabbit-IgGs and BSA-CNT-ITO BSA-monoclonal AFB1 antibodyMWCNTs-COOH-ITO HRP-labeled C. difficile toxin B antibody-MWCNTs-GO Antibody of microcystin-LR-SWCNTs HRP-labeled MC-LR antibody-SWCNHs Antibody FB1-BSA-SWCNTs-CS AFB1 antibody-BSA-HRP-MWCNTs-CS AFB1 antibody-MSC Ionic liquid-GO-Au NPs Rabbit anti-BoNT/E antibody-GNS-PhPhNH2 AFB1 antibody-rGO-ITO AFB1 antibody-GO-Au NPs AFB1 antibody-BSA-rGO

Chronamperometry DPV CV

3.2
721 nmol L 0.25
6 ng dL21 0.25
1.375 ng mL21

1.6 nmol L 0.25 ng dL21 0.08 ng mL21

AFB1 OTA AFB1

[25] [27] [28]

CV and DPV

0.003
320 ng mL21

0.7 pg mL21

C. difficile toxin B

[29]


CV EIS DPV DPV CFFTCV DPV

0
10 0.6 nmol 0.05
20 μg L21 0.01
1000 ng mL21 0.0001
10 ng mL21 0.01
20 ng mL21 2200 nM 10 pg mL21
10 ng mL21

0.6 nmol L21 0.03 μg L21 2 pg mL21 0.1 pg mL21 3.0 pg mL21 0.22 nM 5.0 pg mL21

Microcystin-LR Microcystin-LR FB1 AFB1 AFB1 OTA Botulinum neurotoxin-E

[30] [31] [34] [35] [36] [42] [43]

CV CV CV

0.125
1.5 ng mL21 0.5
5 ng mL21 1024
1 ppt

AFB1 AFB1 AFB1

[44] [45] [46]

Rabbit anti-AFB1 antibody-PtNPsCoTPP-rGO rGO-PPy-PPa Ionic liquid/antibody-G-polymer-Au NPs OTA antibody-GO-PAMAM-Mn21 Monoclonal anti-AFB1 antibodyrGO
Ni NPs-ITO Single strand DNA-rGOae-ss-HSDNA Antibody anti-AFB1-PEDOT-GO-Au NPs

DPV

0.005
5.0 ng mL21

0.12 ng mL21 0.23 ng mL21 1024 ppt (0.1 fg mL21) 1.5 pg mL21

AFB1

[47]

EIS CV EIS CV

10 fg mL21
10 pg mL21 3.2 fM
0.32 pM 0.1 pg mL21
30 ng mL21 1.0
8.0 ng mL21

10 fg mL21 1.0 fM 0.055 pg mL21 0.16 ng mL21

AFB1 AFB1 OTA AFB1

[48] [49] [50] [51]

CV CV and EIS

0.1
70 ng mL21 0.5
25 ng mL21

0.04 ng mL21 11.81 μA ng mL21

AFB1 AFB1

[52] [53]

(Continued)

Table 11.1 (Continued) Surface modification of electrode

Detection technique

Linear range

Limit of detection

Analyzed mycotoxin

Reference

ATM1 antibody-Fe3O4-GO-CdTe QDs

Multifunctional electrochemical analytical system DPV

1.0
1.0 3 105 pg mL21

0.3 pg mL21

AFM1

[54]

0.3
8.5 ng mL21

0.86 ng mL21

OTA

[60]

DPV CV CV and EIS SWV CV CV and EIS

0.15
9.94 ng mL21 1
1000 ng mL21 0.1
10 nM 0.1 pg mL21
10 ng mL21 0 pg L21
1 μg L21 10 pg mL21
100 ng mL21

0.10 ng mL21 1.97 3 1023 ng mL21 0.40 6 0.03 nM 39 fg mL21 7.0 pg L21 8.2 pg mL21

OTA AFB1 AFB1 OTA Microcystin-LR OTA

[61] [62] [64] [65] [66] [68]

Conductometric immune-biosensor DPV and EIS

0.5
10 ng mL21

0.1 ng mL21

AFB1

[69]

0.05
15.00 μg L21

20 ng L21

Microcystin-LR

[70]

1.0 3 1026
20 ng mL21

3.3 3 1027 ng mL21

Zearalenone

[73]


5 pg mL21
750 ng mL21 0.005
15 ng mL21 0.01
12 ng mL21

0.32 μg L21 1.7 pg mL21 1.7 pg mL21 3.0 pg mL21

OTA OTA Zearalenone Zeranol

[79] [80] [81] [82]

Anti-rabbit IgG peroxidase/anti-rabbit IgG-alkaline phosphatase-Au NPsBSA-OTA Antibody OTA-HRP-Au NPs-BSA-OTA Gold electrode-imprinted protein Aptamer-Au-PAMAM dendrimers Au Oct PCs-TB-Ab2 Anti-microcystin-LR-Ag NPs Anti-OTA mouse monoclonal antibodyhorse anti-mouse IgG-colloid Au NPs HRP-AFB1 antibody-Au NPs BSA-anti-MC-LR antibody-L-cysteineAu NPs BSA-antibody-TiO2-Co3O4 Antibody-magnetic beads TiO2/S-BiVO4-Ag2S Antibody-MSC-Au-AgPt TH-HRP-secondary anti-zeranol antibody-nanoporous Au

Photoelectrochemical technique Amperometry
CV and SWV CV

ATM1, Aflatoxins M1; DPV, differential-pulse voltammetry; CFFTCV, Fourier transformation cyclic voltammetry; CV, cyclic voltammetry; EIS, electrochemical impedance spectroscopy; MSC, mesoporous carbon; OTA, ochratoxin-A; PAMAM, poly(amidoamine); PEDOT, poly (3,4-ethylenedioxythiophene); SWV, square-wave voltammetry.

Nanoparticle-integrated electrochemical devices for identification of mycotoxins

291

nanomaterials (MWCNTs, SWCNTs, rGO, and GO), metal NPs, and metal oxide] have been decorated with specific antibodies for the selective detection of mycotoxins in food samples. It was confirmed that analytical performance of electroanalytical techniques (limit of detection, stability, precision, and accuracy) were greatly improved by modifying electrode surfaces with nanomaterial-conjugated biosensors. Importantly, nanomaterial-based electrochemical sensors offer several potential advantages such as high selectivity, sensitivity, reusability, portability, and onsite identification, which exhibit better performance than those of traditional analytical techniques. These studies revealed that the fabrication electrodes with nanomaterials tremendously improved the analytical performance of electroanalytical techniques for the selective and sensitive detection of mycotoxins in food samples. Therefore, we can predict the future developments on the nanomaterial-based electrochemical sensors for the identification of multiple mycotoxins in food and environmental samples with reduced sample preparations at minimal volume of sample.

Acknowledgments S.K.K. acknowledges the Department of Science & Technology, Government of India for financial support (EMR/2016/002621/IPC).

References [1] A. Reunanen, P. Knekt, R.-K. Aaran, A. Aromaa, Serum antioxidants and risk of noninsulin dependent diabetes mellitus, Eur. J. Clin. Nutr. 52 (1998) 89
93. Available from: https://doi.org/10.1038/sj.ejcn.1600519. [2] M.E. Bezerra da Rocha, Fda C.O. Freire, F.E.F. Maia, M.I.F. Guedes, D. Rondina, Mycotoxins and their effects on human and animal health, Food Control 36 (2014) 159
165. [3] H. Hussein, J. Brasel, Toxicity, metabolism and impact of mycotoxins on human and animals, Toxicology 167 (2001) 101
134. Available from: https://doi.org/10.1016/ S0300-483X(01)00471-1. [4] M. Peracia, B. Radic, A. Lucic, M. Pavlovic, Toxic effects of mycotoxins in humans, Bull. World Health Organ. 77 (1999) 754
766. [5] J. Dever, USDA Staff and not necessarily statements of official U. S. Government Greece, Greece Stone Fruit Approved By: 11 (2010) 1
4. [6] S.K. Kailasa, V.N. Mehta, H.-F. Wu, Recent developments of liquid-phase microextraction techniques directly combined with ESI- and MALDI-mass spectrometric techniques for organic and biomolecule assays, RSC Adv. 4 (2014) 16188
16205. [7] S.K. Kailasa, H.F. Wu, Nanomaterial-based miniaturized extraction and preconcentration techniques coupled to matrix-assisted laser desorption/ionization mass spectrometry for assaying biomolecules, Trends Anal. Chem. 65 (2015) 54
72. [8] S.K. Kailasa, K. Kiran, H.-F. Wu, Comparison of ZnS semiconductor nanoparticles capped with various functional groups as the matrix and affinity probes for rapid analysis of cyclodextrins and proteins in surface-assisted laser desorption/ionization time-offlight mass spectrometry, Anal. Chem. 80 (2008) 9681
9688.

292

Handbook of Nanomaterials in Analytical Chemistry

[9] S.K. Kailasa, J.R. Koduru, M.L. Desai, T.J. Park, R.K. Singhal, H. Basu, Recent progress on surface chemistry of plasmonic metal nanoparticles for colorimetric assay of drugs in pharmaceutical and biological samples, Trends Anal. Chem. 105 (2018) 106
120. [10] K.Y. Goud, S.K. Kailasa, V. Kumar, Y.F. Tsang, S.E. Lee, K.V. Gobi, et al., Progress on nanostructured electrochemical sensors and their recognition elements for detection of mycotoxins: a review, Biosens. Bioelectron. 121 (2018) 205
222. [11] A. Chen, S. Chatterjee, Nanomaterials based electrochemical sensors for biomedical applications, Chem. Soc. Rev. 42 (2013) 5425. Available from: https://doi.org/10.1039/ c3cs35518g. [12] A. Azzouz, S.K. Kailasa, S.S. Lee, A.J. Rascon, E. Ballesteros, M. Zhang, et al., Review of nanomaterials as sorbents in solid-phase extraction for environmental samples, Trends Anal. Chem. 108 (2018) 347
369. [13] C.M. Hussain, Handbook of Nanomaterials for Industrial Applications, Elsevier, Amsterdam, Netherlands, 2018. [14] C.M. Hussain, Nanomaterials in Chromatography: Current Trends in Chromatographic Research Technology and Techniques, Elsevier, Amsterdam, Netherlands, 2018. [15] J.C. Vidal, L. Bonel, A. Ezquerra, S. Herna´ndez, J.R. Bertolı´n, C. Cubel, et al., Electrochemical affinity biosensors for detection of mycotoxins: A review, Biosens. Bioelectron. 49 (2013) 146
158. Available from: https://doi.org/10.1016/ j.bios.2013.05.008. [16] B.D. Malhotra, S. Srivastava, M.A. Ali, C. Singh, Nanomaterial-based biosensors for food toxin detection, Appl. Biochem. Biotechnol. 174 (2014) 880
896. Available from: https://doi.org/10.1007/s12010-014-0993-0. [17] A. Rhouati, G. Bulbul, U. Latif, A. Hayat, Z.-H. Li, J. Marty, Nano-aptasensing in mycotoxin analysis: recent updates and progress, Toxins (Basel) 9 (2017) 349. Available from: https://doi.org/10.3390/toxins9110349. [18] G. Bu¨lbu¨l, A. Hayat, S. Andreescu, Portable nanoparticle-based sensors for food safety assessment, Sensors 15 (2015) 30736
30758. Available from: https://doi.org/10.3390/ s151229826. [19] Y. Zeng, Z. Zhu, D. Du, Y. Lin, Nanomaterial-based electrochemical biosensors for food safety, J. Electroanal. Chem. 781 (2016) 147
154. Available from: https://doi. org/10.1016/j.jelechem.2016.10.030. [20] V. Georgakilas, J.A. Perman, J. Tucek, R. Zboril, Broad family of carbon nanoallotropes: classification, chemistry, and applications of fullerenes, carbon dots, nanotubes, graphene, nanodiamonds, and combined superstructures, Chem. Rev. 115 (2015) 4744
4822. [21] R. Alshehri, A.M. Ilyas, A. Hasan, A. Arnaout, F. Ahmed, A. Memic, Carbon nanotubes in biomedical applications: factors, mechanisms, and remedies of toxicity, J. Med. Chem. 59 (2016) 8149
8167. [22] R. Zhang, Y. Zhang, F. Wei, Horizontally aligned carbon nanotube arrays: growth mechanism, controlled synthesis, characterization, properties and applications, Chem. Soc. Rev. 46 (2017) 3661
3715. [23] C.B. Jacobs, M.J. Peairs, B.J. Venton, Review: carbon nanotube based electrochemical sensors for biomolecules, Anal. Chim. Acta 662 (2010) 105
127. [24] P. Ya´n˜ez-Seden˜o, J.M. Pingarro´n, J. Riu, F.X. Rius, Electrochemical sensing based on carbon nanotubes, Trends Anal. Chem. 29 (2010) 939
953. 2010. [25] S.C. Li, J.H. Chen, H. Cao, D.S. Yao, D. Liu, Amperometric biosensor for aflatoxin B1 based on aflatoxin-oxidase immobilized on multiwalled carbon nanotubes, Food Control 22 (2011) 43
49.

Nanoparticle-integrated electrochemical devices for identification of mycotoxins

293

[26] D.-S. Yao, H. Cao, S. Wen, D.L. Liu, Y. Bai, W.J. Zheng, A novel biosensor for sterigmatocystin constructed by multi-walled carbon nanotubes (MWNT) modified with aflatoxin
detoxifizyme (ADTZ), Bioelectrochemistry 68 (2006) 126
133. [27] A. Kaushik, P.R. Solanki, M. Pandey, K. Kaneto, S. Ahmad, B.D. Malhotra, Carbon nanotubes—chitosan nanobiocomposite for immunosensor, Thin Solid Films 519 (2010) 1160
1166. [28] C. Singh, S. Srivastava, M.A. Ali, T.K. Gupta, G. Sumana, A. Srivastava, et al., Carboxylated multiwalled carbon nanotubes based biosensor for aflatoxin detection, Sens. Actuat. B Chem. 185 (2013) 258
264. [29] Y.-S. Fang, S.-Y. Chen, X.-J. Huang, L.-S. Wang, H.-Y. Wang, J.-F. Wang, Simple approach for ultrasensitive electrochemical immunoassay of Clostridium difficile toxin B detection, Biosens. Bioelectron. 53 (2013) 238
244. [30] L.B. Wang, W. Chen, D.H. Xu, B.S. Shim, Y.Y. Zhu, F.X. Sun, et al., Simple, rapid, sensitive, and versatile SWNT-paper sensor for environmental toxin detection competitive with ELISA, Nano Lett. 9 (2009) 4147
4152. [31] J. Zhang, J.P. Lei, C.L. Xu, L. Ding, H.X. Ju, Carbon nanohorn sensitized electrochemical immunosensor for rapid detection of microcystin-LR, Anal. Chem. 82 (2010) 1117
1122. [32] S. Viswanathan, L.C. Wu, M.R. Huang, J.A.A. Ho, Electrochemical immunosensor for cholera toxin using liposomes and poly(3,4-ethylenedioxythiophene)-coated carbon nanotubes, Anal. Chem. 78 (2006) 1115
1121. [33] R.B. Queiros, A. Guedes, P.V.S. Marques, J.P. Noronha, M.G.F. Sales, Recycling old screen-printed electrodes with newly designed plastic antibodies on the wall of carbon nanotubes as sensory element for in situ detection of bacterial toxins in water, Sens. Actuat. B Chem. 189 (2013) 21
29. [34] X. Yang, X. Zhou, X. Zhang, Y. Qing, M. Luo, X. Liu, et al., A highly sensitive electrochemical immunosensor for Fumonisin B1 detection in corn using single-walled carbon nanotubes/chitosan, Electroanalysis 27 (2015) 2679
2687. [35] F.A. Azri, J. Selamat, R. Sukor, Electrochemical immunosensor for the detection of aflatoxin B1 in palm kernel cake and feed samples, Sensors 17 (2017) 2776. Available from: https://doi.org/10.3390/s17122776. [36] Y. Lin, Q. Zhou, Y. Lin, D. Tang, G. Chen, D. Tang, Simple and sensitive detection of aflatoxin B1 within five minute using a non-conventional competitive immunosensing mode, Biosens. Bioelectron. 74 (2015) 680
686. [37] M. Pumera, The electrochemistry of carbon nanotubes: fundamentals and applications, Chem. A Eur. J. 15 (2009) 4970
4978. [38] I. Dumitrescu, P.R. Unwin, J.V. Macpherson, Electrochemistry at carbon nanotubes: perspective and issues, Chem. Commun. (Camb) 45 (2009) 6886
6901. [39] A. Ambrosi, C.K. Chua, A. Bonanni, Electrochemistry of graphene and related materials, Chem. Rev. 114 (2014) 7150
7188. [40] S. Wu, Q. He, C. Tan, Y. Wang, H. Zhang, Graphene-based electrochemical sensors, Small 9 (2013) 1160
1172. [41] D. Chen, L. Tang, J. Li, Graphene-based materials in electrochemistry, Chem. Soc. Rev. 39 (2010) 3157
3180. [42] P. Norouzi, B. Larijani, M. Ganjali, Ochratoxin A sensor based on nanocomposite hybrid film of ionic liquid-graphene nano-sheets using coulometric FFT cyclic voltammetry, Int. J. Electrochem. Sci. 7 (2012) 7313
7324. [43] J. Narayanan, M.K. Sharma, S. Ponmariappan, Sarita, M. Shaik, S. Upadhyay, Electrochemical immunosensor for botulinum neurotoxin type-E using covalently

294

[44]

[45]

[46]

[47]

[48]

[49]

[50]

[51]

[52]

[53]

[54]

[55]

[56] [57]

Handbook of Nanomaterials in Analytical Chemistry

ordered graphene nanosheets modified electrodes and gold nanoparticles-enzyme conjugate, Biosens. Bioelectron. 69 (2015) 249
256. S. Srivastava, V. Kumar, M.A. Ali, P.R. Solanki, A. Srivastava, G. Sumana, et al., Electrophoretically deposited reduced graphene oxide platform for food toxin detection, Nanoscale 5 (2013) 3043
3051. S. Srivastava, M.A. Ali, S. Umar, U.K. Parashar, A. Srivastava, G. Sumana, et al., Graphene oxide-based biosensor for food toxin detection, Appl. Biochem. Biotechnol. 174 (2014) 960
970. J. Basu, S. Datta, C.A. RoyChaudhuri, A graphene field effect capacitive Immunosensor for sub-femtomolar food toxin detection, Biosens. Bioelectron. 68 (2015) 544
549. J. Shu, Z. Qiu, Q. Wei, J. Zhuang, D. Tang, Cobalt-porphyrin-platinum-functionalized reduced graphene oxide hybrid nanostructures: A novel peroxidase mimetic system for improved electrochemical immunoassay, Sci. Rep. 5 (2015) 15113. Available from: https://doi.org/10.1038/srep15113. D. Wang, W. Hu, Y. Xiong, Y. Xu, C.M. Li, Multifunctionalized reduced graphene oxide-doped polypyrrole/pyrrolepropylic acid nanocomposite impedimetric immunosensor to ultra-sensitively detect small molecular aflatoxin B1, Biosens. Bioelectron. 63 (2015) 185
189. Z. Linting, L. Ruiyi, L. Zaijun, X. Qianfang, F. Yinjun, L. Junkang, An immunosensor for ultrasensitive detection of aflatoxin B1 with an enhanced electrochemical performance based on graphene/conducting polymer/gold nanoparticles/the ionic liquid composite film on modified gold electrode with electrodeposition, Sens. Actuat. B Chem. 174 (2012) 359
365. J. Tang, Y. Huang, C. Zhang, H. Liu, D. Tang, Amplified impedimetric immunosensor based on instant catalyst for sensitive determination of ochratoxin A, Biosens. Bioelectron. 86 (2016) 386
392. S. Srivastava, V. Kumar, K. Arora, C. Singh, Md. A. Ali, N.K. Puri, et al., Antibody conjugated metal nanoparticle decorated graphene sheets for a mycotoxin sensor, RSC Adv. 6 (2016) 56518
56526. A. Krittayavathananon, M. Sawangphruk, Impedimetric sensor of ss-HSDNA/reduced graphene oxide aerogel electrode toward Aflatoxin B1 detection: Effects of redox mediator charges and hydrodynamic diffusion, Anal. Chem. 89 (2017) 13283
13289. A. Sharma, A. Kumar, R. Khan, A highly sensitive amperometric immunosensor probe based on gold nanoparticle functionalized poly (3, 4-ethylenedioxythiophene) doped with graphene oxide for efficient detection of aflatoxin B1, Synthet. Metal. 235 (2018) 136
144. N. Gan, J. Zhou, P. Xiong, F. Hu, Y. Cao, T. Li, et al., An ultrasensitive electrochemiluminescent immunoassay for aflatoxin M1 in milk, based on extraction by magnetic graphene and detection by antibody-labeled CdTe quantumn dots-carbon nanotubes nanocomposite, Toxins (Basel) 5 (2013) 865
883. Available from: https://doi.org/ 10.3390/toxins5050865. M. Nasir, N.H. Nawaz, U. Latif, M. Yaqub, A. Hayat, A. Rahim, An overview on enzyme-mimicking nanomaterials for use in electrochemical and optical assays, Microchim. Acta 184 (2017) 323
342. C. Zhu, G. Yang, H. Li, D. Du, Y. Lin, Electrochemical sensors and biosensors based on nanomaterials and nanostructures, Anal. Chem. 87 (2015) 230
249. G. Doria, J. Conde, B. Veigas, L. Giestas, C. Almeida, M. Assunc¸a˜o, et al., Noble metal nanoparticles for biosensing applications, Sensors (Basel) 12 (2012) 1657
1687.

Nanoparticle-integrated electrochemical devices for identification of mycotoxins

295

[58] S.E.F. Kleijn, S.C.S. Lai, M.T.M. Koper, P.R. Unwin, Electrochemistry of Nanoparticles, Angew. Chem. Int. Ed. 53 (2014) 3558
3586. [59] L. Reverte´, B. Prieto-Simo´n, M. Campa`s, New advances in electrochemical biosensors for the detection of toxins: Nanomaterials, magnetic beads and microfluidics systems. A review, Anal. Chim. Acta 908 (2016) 8
21. [60] L. Bonel, J.C. Vidal, P. Duato, J.R. Castillo, Ochratoxin A nanostructured electrochemical immunosensors based on polyclonal antibodies and gold nanoparticles coupled to the antigen, Anal. Method. 2 (2010) 335
341. [61] J.C. Vidal, L. Bonel, P. Duato, J.R. Castillo, Improved electrochemical competitive immunosensor for ochratoxin A with a biotinylated monoclonal antibody capture probe and colloidal gold nanostructuring, Anal. Method. 3 (2011) 977
984. [62] R.A.V. Gutierrez, M. Hedstro¨m, B. Mattiasson, Screening of self-assembled monolayer for aflatoxin B1 detection using immune-capacitive sensor, Biotechnol. Rep. 8 (2015) 144
151. [63] R.A.V. Gutierrez, M. Hedstro¨m, B. Mattiasson, Bioimprinting as a tool for the detection of aflatoxin B1 using a capacitive biosensor, Biotechnol. Rep. 11 (2016) 12
17. ˇ ´ rkova´, L. Mosiello, T. Hianik, [64] G. Castillo, K. Spinella, A. Poturnayova´, M. Snejda Detection of aflatoxin B 1 by aptamer-based biosensor using PAMAM dendrimers as immobilization platform, Food Control 52 (2015) 9
18. [65] T. Zhang, B. Xing, Q. Han, Y. Lei, D. Wu, X. Ren, et al., Electrochemical immunosensor for ochratoxin A detection based on Au octahedron plasmonic colloidosomes, Anal. Chim. Acta 1032 (2018) 114
121. [66] S. Loyprasert, P. Thavarungkul, P. Asawatreratanakul, B. Wongkittisuksa, C. Limsakul, P. Kanatharana, Label-free capacitive immunosensor for microcystin-LR using selfassembled thiourea monolayer incorporated with Ag nanoparticles on gold electrode, Biosens. Bioelectron. 24 (2008) 78
86. [67] A.E. Radi, X. Mun˜oz-Berbel, V. Lates, J.L. Marty, Label-free impedimetric immunosensor for sensitive detection of ochratoxin A, Biosens. Bioelectron. 24 (2009) 1888
1892. [68] X.P. Liu, Y.J. Deng, X.Y. Jin, L.G. Chen, J.H. Jiang, G.L. Shen, et al., Ultrasensitive electrochemical immunosensor for ochratoxin A using gold colloid-mediated hapten immobilization, Anal. Biochem. 389 (2009) 63
68. [69] Y. Liu, Z.H. Qin, X.F. Wu, H. Jiang, Immune-biosensor for aflatoxin B-1 based bioelectrocatalytic reaction on micro-comb electrode, Biochem. Eng. J. 32 (2006) 211
217. [70] P. Tong, S.R. Tang, Y. He, Y.H. Shao, L. Zhang, G.N. Chen, Label-free immunosensing of microcystin-LR using a gold electrode modified with gold nanoparticles, Microchim. Acta 173 (2011) 299
305. [71] L. Lebogang, B. Mattiasson, M. Hedstrom, Capacitive sensing of microcystin variants of microcystis aeruginosa using a gold immunoelectrode modified with antibodies, gold nanoparticles and polytyramine, Microchim. Acta 181 (2014) 1009
1017. [72] P. Kalita, J. Singh, M.K. Singh, P.R. Solanki, G. Sumana, B.D. Malhotra, Ring like self assembled Ni nanoparticles based biosensor for food toxin detection, Appl. Phys. Lett. 100 (2012) 093702. [73] N. Liu, S. Chen, Y. Li, H. Dai, Y. Lin, Self-enhanced photocathodic matrix based on poly-dopamine sensitized TiO2 mesocrystals for mycotoxin detection assisted by a dual amplificatory nanotag, New J. Chem. 41 (2017) 3380
3386. [74] J. Singh, A. Roychoudhury, M. Srivastava, P.R. Solanki, D.W. Lee, S.H. Lee, et al., A highly efficient rare earth metal oxide nanorods based platform for aflatoxin detection, J. Mater. Chem. B 1 (2013) 4493
4503.

296

Handbook of Nanomaterials in Analytical Chemistry

[75] C. Chai, J. Lee, P. Takhistov, Direct detection of the biological toxin in acidic environment by electrochemical impedimetric immunosensor, Sensors 10 (2010) 11414
11427. [76] A. Vig, X. Munoz-Berbel, A. Radoi, M. Cortina-Puig, J.L. Marty, Characterization of the gold-catalyzed deposition of silver on graphite screen-printed electrodes and their application to the development of impedimetric immunosensors, Talanta 80 (2009) 942
946. [77] H. Kuang, W. Chen, D.H. Xu, L.G. Xu, Y.Y. Zhu, L.Q. Liu, et al., Fabricated aptamerbased electrochemical “signal-off” sensor of ochratoxin A, Biosens. Bioelectron. 26 (2010) 710
716. [78] L. Yang, Y. Zhang, R. Li, C. Lin, L. Guo, B. Qiu, et al., Electrochemiluminescence biosensor for ultrasensitive determination of ochratoxin A in corn samples based on aptamer and hyperbranched rolling circle amplification, Biosens Bioelectron. 70 (2015) 268
274. ´ ngel, L.A. Escarpa, Disposable electrochemical magneto [79] A. Jodra, M. Herva´s, M. A immunosensor for simultaneous simplified calibration and determination of Ochratoxin A in coffee samples, Sens. Actuat. B Chem. 221 (2015) 777
783. [80] J. Feng, Y. Li, Z. Gao, H. Lv, X. Zhang, D. Fan, et al., Visible-light driven label-free photoelectrochemical immunosensor based on TiO2/S-BiVO4@Ag2S nanocomposites for sensitive detection OTA, Biosens. Bioelectron. 99 (2018) 14
20. [81] L. Liu, Y. Chao, W. Cao, Y. Wang, C. Luo, X. Pang, et al., A label-free amperometric immunosensor for detection of zearalenone based on trimetallic Au-core/AgPt-shell nanorattles and mesoporous carbon, Anal. Chim. Acta 847 (2014) 29
36. [82] R. Feng, Y. Zhang, H. Li, D. Wu, X. Xin, S. Zhang, et al., Ultrasensitive electrochemical immunosensor for zeranol detection based on signal amplification strategy of nanoporous gold films and nano-montmorillonite as labels, Anal. Chim. Acta 758 (2013) 72
79.

Further reading R. Eivazzadeh-Keihan, P. Ashazadeh, M. Hejazi, M. de la Guardia, A. Mokhtarzadeh, Recent advances in nanomaterial-mediated bio and immune sensors for detection of aflatoxin in food products, Trends Anal. Chem. 87 (2017) 112
128.

Functional nanomaterial-derived electrochemical sensor and biosensor platforms for biomedical applications

12

Govindhan Maduraiveeran1 and Wei Jin2 1 Material Electrochemistry Laboratory, Department of Chemistry, SRM Institute of Science and Technology, Kattankulathur, Tamil Nadu, India, 2National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, P.R. China

12.1

Introduction

Development of functional nanomaterials possesses enormous interest on catalysis, sensors and biosensors, energy conversion, and energy storage devices over the last decade. A diversity of functional nanomaterials with well-controlled physicochemical features, shape, and dimension is created by significant advances in synthetic approaches. Owing to the high reactive surface area and small particle size, nanomaterial-based electrochemical sensors and biosensors provide many advantages [1]. The high surface-area-to-volume ratio permits higher electrocatalysis and sensing response, signifying noteworthy benefits over macroscale materials for biomedical applications [2]. The most important nanomaterials used for the biomedical applications are schematically shown in Fig. 12.1 [3]. The functional nanomaterial-based electrodes offer various chemical composition, surface texture, crystal structure perfection, crystallographic axis orientation, etc., control electron-transport mechanism on electroanalytical in vivo and in vitro measurements to diagnose diseases and to monitor the clinical status of patients at various levels [4]. The development of functional nanomaterials that are capable of interacting with specific biological compounds is currently facing significant challenges. On the other hand, nanoentity support matrix interactions and critical structural parameters also affect the catalytic and biosensing properties of the nanomaterials [5]. In medical diagnostics and clinical analysis, the use of electrochemical biosensors in the detection of scrupulous cell-type or precise anatomical sites in a human body is potentially expanding. The nanobiosensors offer high sensitivity and ease of miniaturization, which may assist in developing a new pattern for clinical and field-deployable analytical instruments [6]. Handbook of Nanomaterials in Analytical Chemistry. DOI: https://doi.org/10.1016/B978-0-12-816699-4.00012-8 Copyright © 2020 Elsevier Inc. All rights reserved.

298

Handbook of Nanomaterials in Analytical Chemistry

Figure 12.1 Scheme for advanced nanomaterials used as sensing materials for electrochemical biomedical applications.

Electrochemical biosensors are dominant analytical tools for the detection and determination of numerous biomarkers owing to their portability, self-containment, and low cost. The advanced functionalized nanomaterial-based electrochemical sensor methods are sensitive and selective tools, which are highly essential in the field of biomedical and certainly in many areas of analytical sciences [7]. It has been shown that numeral electrochemical biosensing approaches have been established based on numerous nanostructures for various biomedical applications. The junction of functional nanomaterials, microfabrication of electrodes, and sensor engineering technology is an efficient approach for the detection of level of blood, metabolites, etc. [8 10]. This chapter mainly focuses on the progress in the growth of functional nanomaterial-derived electrochemical sensors and biosensors for the detection of potent biomedically important analytes, which are presented in the clinical, pharmaceutical, biomedical, and biological fluids. It is believed that the perceptions discussed in this chapter will impetus on the advanced nanomaterials, construction, and the integration of the sensor platforms for prolonging the human life.

Functional nanomaterial-derived electrochemical sensor

12.2

299

Noble metallic nanoparticles

Noble metallic nanoparticles (NPs), including gold (Au), silver (Ag), platinum (Pt), palladium (Pd), corresponding bi- or trimetallic alloys, and core-shell NPs have primarily engaged in the progress of electrochemical sensors for biomedical analyses owing to their exceptional size- and shape-dependent physical, chemical, and electrochemical properties [11]. Noble metal NP-derived electrochemical sensors possess a great potential to improve both sensitivity and selectivity via tuned signal amplifications. For realistic real-world biomedical applications, the development of functional nanomaterials with minimal toxicity and environmental impact via nanoengineering has a huge impact over selective targeting of specific cells and tissues of interest, as well as to clearly identify the affected tissues. Noble metalbased NPs have been directed toward the development of several analytical approaches for clinical, pharmaceutical and medical diagnostics, cancer therapeutics, etc. [12]. The synthesis of metal NPs, biofunctionalized NPs, and nanocomposites or nanohybrids has fascinated in the design of sensor and biosensors for numerous biomedical applications.

12.2.1 Gold nanoparticles Owing to the unique properties such as physiochemical properties, high surface area, greater stability, and complete recovery in biochemical redox reactions, significant efforts have been made in the expansion of the Au NP-based electrochemical sensor and biosensor platforms for numerous biomedical applications [13 15]. Au NPs and their functional nanocomposites have been recognized as potential candidate in the area of biomedical research because of the following merits: (1) simple preparation methods; (2) easy fabrication process; (3) high chemical stability; (4) great biocompatibility; (5) wide electrochemical potential range; and (6) high catalytic activity, which open the opportunity for the miniaturization of sensing platforms, offering excellent sensing and biosensing prospects in near future [13,16,17]. Au NPs have been widely used in the field of nanomedicine because of their high biocompatibility with wide range of drugs or biomarkers [18,19]. It has been shown that the comparative concentration of plasma S-nitrosothiol derivatives (RSNOs) might be connected with inflammatory conditions and various diseases [19,20]. The accurate sensing of RSNOs in biological medium using Au NP-based sensor platform has recently been developed with a detection limit of B100 nM by Baldim et al. [19]. The Au NP-based electrochemical sensor for the detection of RSNOs was performed in the presence of free thiols through RSNOs decomposition by Au NPs with an ultra-microelectrode [20]. Wang et al. have established hydroxylamine sensor using Au NPs immobilization on metal 2 metalloporphyrin networks (Au-NPs/MMPF-6(Fe)) via electrostatic adsorption [21]. The developed sensor showed a couple of linear dynamic ranges, 0.01 1.0 and 1.0 20.0 μM L21 with a low detection limit of 4.0 nM (S/N 5 3). The integration of Au NPs and MMPF-6(Fe) offered a potential hydroxylamine

300

Handbook of Nanomaterials in Analytical Chemistry

sensor because of its strong catalytic sites, enhanced electrochemical active sites, and their soaring electronic conductivity. Electrogenerated chemiluminescence (ECL) biosensor platform based on Au nanomaterials for clinical application has displayed several advantages and numerous commercial ECL systems in clinical analyses. For instance, Dong et al. recently have demonstrated ECL aptasensor based on Au NPs/graphene oxide (Au-NPs/GO) nanocomposites [22]. The ECL aptasensor exhibited responsive and discriminatory detection of adenosine triphosphate in the range of 0.02 200 pM with a low detection limit of 6.7 fM (S/N 5 3). Recently, Maduraiveeran et al. developed an amperometric sensor for acetaminophen without any help of electrochemically active redox mediators and enzymes using bimetallic Au nickel (Au-Ni) NPs (Fig. 12.2) on Ti substrate [23]. This sensor platform showed high sensitivity of 0.2 μA nM21 cm22 with a correlation coefficient (R2) of 0.99 and an extensive linear range starting from 0.0 to 1.75 μM with a calculated lowest sensor limit of 0.51 nM (S/N 5 3). Chauhan and coworker have developed an electrochemical biosensor using nanocomposite of Au NP-embedded N-doped graphene nanosheets for the detection of glycated hemoglobin (HbA1c) [24].

Figure 12.2 SEM images obtained for bare Ti electrode (A) and Au-NPs (B), Ni-NPs (C), and Au-Ni-NPs (D) modified Ti electrode. Source: Reprinted from G. Maduraiveeran, R. Rasik, M. Sasidharan, W. Jin, Bimetallic goldnickel nanoparticles as a sensitive amperometric sensing platform for acetaminophen in human serum, J. Electroanal. Chem. 808 (2018) 259 265 with permission from Elsevier.

Functional nanomaterial-derived electrochemical sensor

301

The fabricated biosensor showed an extensive linear collection from 0.3 to 2000.0 μM with a low detection limit of 0.2 μM. The electrochemical HbA1c biosensor exhibited an excellent selectivity toward the intrusive varieties including ascorbic acid (AA), uric acid (UA), triglycerides, bilirubin, glucose, and urea.

12.2.2 Silver nanoparticles Ag NP-based electrochemical sensors and biosensors have made significant impact on biomedical applications due to their high conductivity, amplified electrochemical signal, and excellent biocompatibility. Over the last two decades, enormous efforts have been made toward the design of novel analytical methods for various analytes such as disease markers, biological and infectious agents in the early-stage detection of disease, and other physiological threats based on Ag NPs and their nanocomposites [25 28]. The construction of nanocomposite based on Ag NPs with matrices such as metal oxides, silicate networks, polymers, graphene, fibers, and dendrimers led to enhanced biosensing performance because of the versatile nature of the materials [29 32]. The sensitivity and stability of the biosensor platform depend on the dispersion and prevention of the aggregation of Ag NPs in the network or matrices. Sheng et al. have recently constructed a hydrogen peroxide (H2O2) sensor using Ni-doped Ag@C (Ni/Ag@C) nanocomposites [31], which exhibited a linear range of 0.03 17.0 mM with a detection limit of 0.01 mM (S/N 5 3). Another electrochemical detection method for moxifloxacin hydrochloride was developed by Fekry using carbon paste (CP) modified with Ag NPs [25]. The sensor showed a sensing limit of 2.9 nM and it successfully tested in Delmoxa tablet and human urine. The homogeneous dispersion of Ag NPs on reduced graphene oxide (rGO) as a nanocomposite was used for the electrochemical oxidation of NO [33]. Amperometric i t curve technique was used to detect NO based on the optimized rGO Ag nanocomposite-modified electrode and showed a detection limit of 2.8 μM. Thus Ag-based biosensor platform could serve as an ideal alternative to other sensors based on other noble metals and polymeric nanomaterials for detection of NO. The same research group also developed another nonenzymatic H2O2 sensor based on rGO-Nafion@Ag6 (rGO-Nf@Ag6) nanohybrid using amperometric method [32]. The rGO-Nf@Ag6 nanohybrid demonstrated a low detection limit of 0.5 μM with a sensitivity of 0.45 μA μM21. Further, rGO-Nf@Ag6 nanomaterial can serve as a highly selective electrochemical sensor for the detection of H2O2 in the presence of NaCl, urea, glucose, dopamine (DA), UA, and AA. In addition, the sensor was highly stable for B5.0 days and showed high reliability with good accuracy and precision for H2O2 sensing in apple juice. Ag NPs and their nanocomposites can significantly improve the electrochemical activity by exhibiting higher catalytic performance in comparison to their bulk material counterpart owing to large reactive surface area.

302

Handbook of Nanomaterials in Analytical Chemistry

12.2.3 Platinum nanoparticles Pt-based nanomaterials have attracted widespread interest in the field of electrochemical biosensors for biomedical applications over the last decade because of their distinctive electronic and electrocatalytic properties [34 37]. The electron-transfer process of the Pt NPs can be drastically influenced by material compositions, surface reactive environment, crystalline plane and orientation. Pt-based functional nanocomposites provide effectual electrode materials for the extension of their novel characteristics [36 41] toward the development of reliable, fast, and precise bioanalytical methods for the detection of various biomarkers and early-stage detection of diseases [36,39,40,42,43]. Abella´n-Llobregat et al. have developed a flexible electrochemical sensor for glucose determination in human perspiration based on Pt-decorated graphite and glucose oxidase (GOx) [44]. The sensor was demonstrated for the detection of glucose with a linear range of 0.0 0.9 mM and a low detection limit (6.6 mM). This skin-worn sensor had been effectively applied to real human perspiration samples, verifying an appealing method for noninvasive glucose sensing. The real samples were collected from volunteers without any diabetes history after an intense sport session, which were performed by chronoamperometry by applying at 20.35 V. Parrilla et al. developed paper-based high-performance potentiometric sensor for sensing glucose in biological fluids in a wide linear range from 0.1 to 10 mM with a limit of detection of 0.1 mM [45]. Functional Pt nanomaterial-based sensor platforms have been prepared to enhance the sensitivity and selectivity toward the biomolecules detection [46 48]. There are a number of reports available for embedding multiplicity of nanomaterials for diverse electrochemical sensing applications. Shahid et al. have established an electrochemical sensor using rGO cobalt oxide (Co3O4) nanocube@Pt nanocomposite for the detection of NO [48]. The obtained impressive catalytic activity of the rGO Co3O4@Pt nanocomposite was ascribed to the synergistic effect of metal oxide nanocubes and Pt NPs present in the rGO sheets. This sensor exhibited a low detection limit of 1.73 μM (S/N ratio of 3) with a wide linear range of 10 650 μM using the amperometric i t curve technique. Govindhan et al. have fabricated an exceedingly sensitive electrochemical sensor for NO based on a nanocomposite made up of Pt-tungsten NPs, rGO and Ionic-liquid (IL) (PtW/rGO-IL) [49]. In this sensor design, there were no capping agents used, which are commonly present on the NPs surface to avert the NPs agglomeration and they might slab mass transport and electron transfer, thereby lowering the sensor performance. As presented in Fig. 12.3A, the extensive distribution of PtW NPs in the rGO-IL nanocomposite with an average particle size of B7.3 nm exhibited high crystalline nature (Fig. 12.3B). The detection limit was found to be 0.13 nM with high sensitivity (3.01 μA μM21 cm2) and good specificity against electroactive interferences. Fig. 12.3(C F) depicts the sensing of NO on the PtW/rGO-IL electrode through i t and differential pulse voltammetric (DPV) techniques. The NO sensor was also further demonstrated to selectively distinguish NO in genuine human serum and urine samples, confirming practical application.

Functional nanomaterial-derived electrochemical sensor

303

Figure 12.3 SEM image of the PtW/rGO-IL (A), X-ray diffraction (XRD) pattern of the rGO-IL (red), W/rGO-IL (blue), Pt/rGO-IL (pink), and PtW/rGO-IL (green) (B). Amperometry (C) and DPV (E) responses of the PtW/rGO-IL electrode for sensing of NO and the correponding calibration plots (D and F). Source: Reprinted from M. Govindhan, A. Chen, Enhanced electrochemical sensing of nitric oxide using a nanocomposite consisting of platinum-tungsten nanoparticles, reduced graphene oxide and an ionic liquid, Microchim. Acta 183 (2016) 2879 2887 with permission from Springer.

12.2.4 Palladium nanoparticles Pd NPs have immersed much awareness in the field of biomedical applications due to their huge catalytic and sensor activities. The size- and shape-controlled production of Pd NPs is imperative for facile selective catalytic and sensing properties toward various chemical and biological analytes [50 52]. The relatively large abundance of Pd over other noble metals such as Au and Pt makes it a cheaper substitute for application in various electrochemical sensing and biosensing platforms

304

Handbook of Nanomaterials in Analytical Chemistry

[50,53]. Owing to unique electronic properties, improved catalytic and selective sensing performance, a variety of Pd nanomaterials such as nanocomposites, bimetallic NPs, metal oxide nanomaterials, and carbon nanomaterials with variable composition have been investigated for the detection of numerous biomarkers over the last decade [54 56]. Rahi et al. have demonstrated an electrochemical genosensor for Brucella using Pd NPs deposited on an Au surface by applying constant potential [54]. Brucellosis, an infectious disease, is affected by the Gram-negative bacteria of the genus Brucella and this infection may be transmitted to people by contacts through bacteria-contaminated animal products or animals [54]. Pd NPs are used as a transducer, which is used to immobilize a Brucella-specific probe. The method of immobilization and hybridization was achieved by voltammetric technique. This sensor exhibited a linear calibration range from 1.0 pM to 0.1 aM with a low detection limit of 27 zM, while it showed excellent stability for 30 days if stored in the refrigerator at 4oC. The synthesis of bimetallic Au-Pd NPs is one of the most % preferred alloys in catalytic and sensing studies, which were effectively applied in sensing drugs [55,56]. The electrochemical sensor with Au and Pd NP-modified nanoporous stainless steel (Au-Pd/NPSS) electrode for concurrent sensing levodopa and UA in urine, blood serum, and levodopa C-Forte tablet was developed by Rezaei et al. [56]. In order to obtain better sensitivity and selectivity, the metal NP-based nanocomposite containing graphene and IL have been established for sensing DA, nifedipine, hydroquinone, NO, DNA, etc. [49,57,58]. Wang et al. have recently prepared a nonenzymatic glucose sensor using homogenously dispersed Pd NPs on graphene sheet and IL [59]. A number of IL were used and optimized toward the detection of glucose and AA using Pd-NPs/GNss-IL electrode. Butyl methyl pyrrolidinium bis (trifluoromethanesulfonyl) imide (BMP TFSI) IL was more constructive for sensing glucose, whereas butylmethylpyrrolidinium dicyanamide (BMP DCA) IL was beneficial for high sensitivity toward the sensing of AA with Pd-NPs/GNss-IL electrode in 0.1 M NaOH. Noble metal NPs may easily enhance the electrochemical sensing and biosensing performance as they show higher sensitivity, good specific catalytic activity, quick response time, and good biocompatibility, which may expedite the design of advanced applications in biological, pharmaceutical, clinical, and point-of-care diagnostics.

12.3

Metal oxide nanomaterials

Metal oxide nanomaterials are widely used in numerous fields such as electrochemistry, soft magnetism, catalysis, and sensor. Owing to tremendously reduced dimension, huge surface-area-to-volume ratio, specific facet exposure, and the Debye length comparable to its dimensions, metal oxide nanomaterials may significantly improve sensitivity and/or selectivity [60 66]. Metal oxide nanomaterials have been widely utilized as effective electrocatalysts for sensing various analytes in the

Functional nanomaterial-derived electrochemical sensor

305

field of biology and biomedicine because of their strong electrocatalytic activity, low cost, and high organic capture ability [67 69]. A variety of metal oxide NPs have been used in electroanalysis, including cerium oxide (CeO2), copper oxide (CuO), nickel oxide (NiO), iron oxide (Fe2O3), cobalt oxide (Co3O4), manganese oxide (MnO2), zinc oxide (ZnO), titanium oxide (TiO2), tin oxide (SnO2), and cadmium oxide (CdO).

12.3.1 Cerium oxide nanomaterials CeO2 nanomaterial is one of the central functional rare earth oxides and it reached momentous interest in the field of biosensors due to the easy immobilization of enzyme or protein on the surface of electrode and its tremendous catalytic activity. Recently, Bracamonte et al. have developed an electrochemical H2O2 sensor based on the integration of single-walled carbon nanohorns with CeO2 (CeO2/SWCNH) catalysts [70]. The fabricated CeO2/SWCNH electrode exhibited an excellent sensor performance toward H2O2 (LOD of 0.1 mM). The nanocomposite sensor displayed high stability for over 2 weeks with high reproducibility. The versatility of the developed sensor was examined in commercial samples of milk and cleaning liquid, showing a remarkable selectivity toward H2O2 even in very complex matrices. In particular, the immobilization of primary antibody (Ab1) in an immunosensor with sandwich-type is crucial point to increase sensitivity. It has been shown that making a nanocomposite with other semiconductor oxides is an efficient mode to improve its sensing ability through synergistic effect.

12.3.2 Copper oxide nanomaterials CuO nanomaterials offer versatile functions such as various valence states, tunable electron-transport performance, hierarchical nanostructures, and high surface area. The exploration of CuO nanomaterials has been effectively employed in numerous sensing and biosensing applications. Yang et al. have demonstrated recently a nonenzymatic glucose sensing using nanoneedle-like CuO on N-doped rGO (CuO/ N-rGO) in 0.2 M NaOH [71]. The CuO/N-rGO sensor demonstrated a rapid response to glucose with a wide linear range between 0.5 and 639.0 μM with a lowest detection limit of 0.01 μM. This three-dimensional (3D) nanohybrid architecture of the electrode may prominently increase the interfacial communicating area by offering high reactive sites for glucose housing, which condensed the diffusion length and improve the reactivity. In addition, this glucose sensor was effectively applied for the detection of glucose in human serum samples. Li et al. have developed Cu2O@CeO2-Au nanocomposites for the sensing of prostate-specific antigen [72]. Synergetic consequence displays in the Cu2O@CeO2 core-shell decorated with Au NPs (Cu2O@CeO2/Au-NPs), showing superior electrocatalytic activity for H2O2 reduction than pure Cu2O, Au-NPs, and Cu2O@CeO2. This immunosensor demonstrated a wide linear range, 0.1 pg mL21 100 ng mL21 and showed a low detection limit of 0.03 pg mL21 (S/N 5 3).

306

Handbook of Nanomaterials in Analytical Chemistry

12.3.3 Magnetic nanomaterials Owing to high accessible and active surface area and superior electron-transfer behavior, magnetic nanomaterials such as NiO, Fe2O3, and Co3O4 have been measured as promising materials for superior electrochemical biosensors. Hierarchical porous metal oxide architectures with controlled surface structure and dimension have inward and ample range of fields. Hierarchical porous Co3O4/graphene (GR) was also used as an effective enzyme-free glucose sensor [73]. Fig. 12.4A and B shows scanning electron microscopic (SEM), transmission electron microscopic (TEM) image, and energy dispersive spectroscopic (EDS) of the Co3O4/GR microsphere, revealing that graphene sheets were aggregated and interconnected with Co3O4. The EDS mapping revealed the concurrence and regular dispersal of Co3O4 on graphene sheets. As presented in Fig. 12.4C F, the Co3O4/GR-constructed electrode demonstrated high sensitivity and selectivity toward glucose detection. The application of binary metal oxides has become progressively dominant due to the lack of efficient protocols to upsurge the action of an individual metal oxide. Recently, it has been demonstrated that noble metal NPs deposited on various semiconducting oxide provisions are catalytically energetic due to the noble metal NPs polarization at the interface [47,67]. In several cases, metal oxide nanomaterials are used as backing materials for the dispersion of noble metal NPs due to its much higher catalytic activity than the single-component nanomaterials [74]. The enhanced catalytic activity is often associated to the synergetic consequence that arises at the boundary of metal and oxide support [75,76]. Metal oxide NPs offered a biocompatible atmosphere for the functionalization of the electrode by the immobilization of enzymes and augment the sensitivity of the electrode via easing electron transfer. The enzymes, acetylcholine esterase and choline oxidase were immobilized on the surface of Fe2O3 NPs and poly(3,4ethylenedioxythiophene) (PEDOT)-rGO nanocomposites were used as the sensing electrode materials for the sensitive detection of acetylcholine [77]. This biosensor showed a linear range between 4.0 nM and 800.0 μM with a low detection limit of 4.0 nM. Han et al. have established a glucose biosensor based on genetically engineered M13@MnO2/GOx nanowires [78]. This biosensor demonstrated a wide linear range from 5.0 μM to 2.0 mM with a low detection limit of 1.8 μM. Numerous advances have been made in the field of design and uses of electrochemical sensor based on the metal oxides and their nanocomposites. The development of these sensor systems may lead to significant advantages in terms of simplicity, rapid response, cost, and robotics for various sensing applications toward the monitoring of biomolecules in cell.

12.4

Carbon nanomaterials

Carbon-based nanomaterials [single-walled carbon nanotubes (SWNTs), multiwalled carbon nanotubes (MWNTs), SWCNHs], buckypaper, graphene, fullerenes (e.g., C60), etc. afford many significant benefits because of their extraordinary

Functional nanomaterial-derived electrochemical sensor

307

Figure 12.4 SEM image (A) and TEM-based EDS mapping (B) of hierarchical Co3O4/G microsphere. (C) The i t responses of Co3O4/G electrode to flow injection of glucose (0.02 18.0 mM). (D) Corresponding calibration plot. (E) The i t responses to the successive addition of interfering compounds, including 0.2 mM ascorbic acid (AA), uric acid (UA), and dopamine (DA). (F) Variation of the response current of sensor to 5.0 mM glucose with injection number. Source: Reprinted from M. Yang, J.M. Jeong, K.G. Lee, D.H. Kim, S.J. Lee, B.G. Choi, Hierarchical porous microspheres of the Co3O4@graphene with enhanced electrocatalytic performance for electrochemical biosensors, Biosens. Bioelectron. 89 (2017) 612 619 with permission from Elsevier.

surface-to-volume ratio, great electrical conductivity, chemical durability, biocompatibility, and strong mechanical strength [79 82]. These novel functionalities of carbon materials are accountable for the enlargement of a widespread variability of versatile carbon-based sensing electrodes, which exhibit great sensitivities and low sensing limits toward various biological and biomedical analytes. The morphology

308

Handbook of Nanomaterials in Analytical Chemistry

Figure 12.5 Scheme for the functionalization of rGO-NiO nanocomposite with antibody for the sensitive detection of low-density lipoprotein. Source: Reprinted from M.A. Ali, C. Singh, K. Mondal, S. Srivastava, A. Sharma, B.D. Malhotra, Mesoporous few-layer graphene platform for affinity biosensing application, ACS Appl. Mater. Interfaces 8 (2016) 7646 7656 with permission from American Chemical Society.

of functionalized carbon nanomaterials creates more appealing features that assist their enhanced sensitivity, selectivity, and stable response. The reactive surface functional groups, edge-plane-like sites, and impurities may also be responsible for the tremendous electrocatalytic and sensing performance of carbon nanomaterials [83,84]. Many advances have been explored on carbon nanomaterials in recent years, both through continual development of the existing or new fabrication techniques for the integration of sensor. For instance, Ali et al. recently established a sensor (Fig. 12.5) for low-density lipoprotein molecules based on antiapolipoprotein B 100 functionalized carbon nanomaterials and NiO as nanocomposites for molecules and it showed a low detection limit of 5 mg dL21 concentration with a linear range of 0 2 130 mg dL21 [85].

12.4.1 Carbon nanotubes Carbon nanotubes (CNTs) have quite a lot of fascinating properties associated to their structure, functionality, morphology, and aptness in hybrid or composite materials due to their hollow cylindrical tubes comprising graphitic carbon with an extraordinary aspect proportion and sp2 hybridization. CNTs can be mainly categorized as SWNTs, double-walled nanotubes, and MWNTs contingents on the number of graphite layers. In particular, CNTs have intensively explored to improve the

Functional nanomaterial-derived electrochemical sensor

309

performance of sensing and biosensing platforms due to their unique chemical and physical properties. The functionalized CNTs reveal distinctive properties that could enable diverse clinical, pharmaceutical, and medical applications. The chemical functionalities can easily be conjugated and tuned for the modification of these tubular structures. Delivery of diverse therapeutic agents such as drugs, peptides, proteins, genes, and immune modulators via the biological membrane has easily achieved using the functionalized CNTs. Venton and coworkers have demonstrated an electrochemical in vivo DA sensor based on metal microelectrodes modified with CNTs [86]. It has been found that CNT-coated niobium (CNT-Nb) microelectrode exhibited higher sensitivity and lower ΔEp value than the CNTs grown on carbon fibers (CFs) or other metal wires. The CNT-Nb sensor demonstrated a low detection limit of 11 6 1 nM for DA. The CNT-Nb sensor was also used to detect stimulated DA release in anesthetized rats and demonstrated high sensitivity with rapid measurements in vivo. The CNTNb sensor was stable for .4.0 h of nonstop measurement and thus able to quantify the stimulated DA release in anesthetized rats. The design and synthesis of functional CNTs that focus on specific biological and biomedical applications are highly attractive because of high selectivity, accuracy, and long-term stability toward in vivo biosensing in live brains. Zhang et al. have designed an electrochemical AA sensor for accurately measuring AA levels in live brain using aligned carbon nanotube fiber (CNF) as a microsensor [87]. The sensor demonstrated that the AA concentration was measured to be 259.0 6 6 μM in cortex, 264.0 6 20 μM in striatum, and 261.0 6 21.0 μM in hippocampus, respectively, under normal conditions. Fig. 12.6 shows the pictorial representation, optical images, and the DPV results of in vivo measurements for determining AA in rat brain. This sensor provided a simple methodology for the integration of high-performance biosensors with other neurotransmitters, which might inspire new sensing techniques in brain medical research. Nanocomposite of CNTs and various noble metal and metal oxide nanomaterials have been used as electrocatalyst to enhance the sensing and biosensing performance toward biomedical research [88 90]. Highly monodisperse Ni-NPs supported on functionalized MWCNT (Ni@f-MWCNT)-based nonenzymatic glucose sensor were studied by Baskaya et al. [88]. The Ni@f-MWCNT-based sensor showed a linear range of 0.05 12.0 mM and a low detection limit of 0.021 μM. The novel surface structure, the definite interfaces between Ni and f-MWCNT, and high surface area led to enhanced electrochemical sensing performance, which also showed high stability (over 10 weeks). In order to increase the biocompatibility of CNT-based nanomaterials, the biopolymer, chitosan (CS) has been used for electrochemical sensor application. Bal et al. have developed an electrochemical diethylstilbestrol (DES) sensor based on Au-NPs/MWCNT-CS [89]. It was found that DES has many adverse effects on human body by causing damage to genetic elements, which is forwarded to transmutations in genes, and indorse cancers. The Au-NPs/MWCNT-CS sensor exposed a low detection limit of 24.3 fg mL21 and the sensing range of 0.1 1026 mg mL21. The combination of CNTs and graphene is reflected as an exceptional sensing candidate for production of sensitive, durable,

310

Handbook of Nanomaterials in Analytical Chemistry

Figure 12.6 (A) Schematic illustration of in vivo setup for the sensing of ascorbic acid in rat brain. (B) Optical images prior to- and after the stereotaxic implant into the brain. (C) DPV responses measured at the CNF microelectrode in the striatum of normal rat (I) and rat brain models of AD (II). (D) DPV responses recorded at the CNF microelectrode in the striatum of the rat brain model of AD prior to (I) and after (II) injection of AAox. Source: Reprinted from L. Zhang, F. Liu, X. Sun, G.F. Wei, Y. Tian, Z.P. Liu, et al., Engineering carbon nanotube fiber for real-time quantification of ascorbic acid levels in a live rat model of Alzheimer’s disease, Anal. Chem. 89 (2017) 1831 1837 with permission from American Chemical Society.

and low-cost electrochemical sensor due to the large number of carboxyl groups, reduced volumes, and upright electrical conductivity [91 95]. Recently, Arvand et al. have established nanocomposite of graphene quantum dots (GQDs), Fe3O4 NPs, and f-MWCNT (Fe3O4@GQD/f-MWCNT) for the sensitive detection of progesterone (P4) in human serum and pharmaceutical yields [91]. The flexible and wearable electrochemical sensor can be able to quantify in situ sweat metabolites and secretions. It is considered to be a potential method for real-time monitoring of mechanically induced biochemical signals during mechanotransduction in sensitive cells and tissues. The great challenges still continue in constructing high-performance flexible electrochemical sensors during repeated stretching for biological and biomedical applications. In particular, CNT-based thin films onto or between stretchable substrates of highly elastic polydimethylsiloxane (PDMS), Ecoflex was designed for electrochemical sensor. The real-time

Functional nanomaterial-derived electrochemical sensor

311

monitoring of NO level from mechanically sensitive cells is of great importance because NO generation from cells through mechano-transduction was dramatically influenced by mechanical forces, including strain, tension, compression, and shear stress. Recently Jin et al. have developed a versatile approach to fabricate CNT-based stretchable and transparent electrochemical NO sensors by binding SWCNT with conductive polymer of PEDOT to form composite films [96]. CNTs still have vast potential in the field of biomedical applications due to their novel characteristics including high aspect ratio, catalytic properties, amenable to surface functionalization, conductive nature, and ability to maintain structural integrity. In addition, the capability to transfer electrons at a rapid pace at the electrode and electrolyte interface permits them to be effectively applied in ultrasensitive, discerning, and forceful chemical sensors, and biosensors.

12.4.2 Graphene Enormous research efforts have been dedicated on the graphene and graphene-based nanocomposite materials for various applications. Graphene is an indeterminately extended two-dimensional carbon network with a hexagonal lattice resembling a honeycomb structure that exhibit high sensitivity, great selectivity, good stability, low over potential, wide potential window, negligible capacitive current, and excellent electrocatalytic activity [97]. It presents numerous interesting properties such as huge specific surface area, giant conductivity and transparency, excellent mechanical strength and flexibility, strong ambipolar electric field effect, good thermal and electrical conductivity, and excellent electronic properties. The various forms of graphene such as GO, rGO, and graphene nanorippons are possible after freeing the CNTs. The functionalized graphene using various materials, including organic and biomolecules, metal and metal oxide NPs, polymers, and enzymes are often used for achieving improved sensing and biosensing performance toward biomedical applications [40]. Over the past few years, many researchers have reviewed graphene-based nanomaterials and their electroanalytical applications toward biological, biomedical, food safety, and environmental applications [40,97 99]. Adhikari et al. have developed a sensor using electrochemically reduced graphene oxide (ERG) for sensitive sensing acetaminophen in pharmaceutical formulations and human body fluids [100]. The superb electrical conductivity, great surface area, and oxygen-related defects of ERG create them as sensitive and rapid electrochemical sensing platforms toward acetaminophen detection. The ERG-based sensor demonstrated a low detection limit of 2.13 nM and showed a linear range, 5.0 nM 800.0 μM. In addition, this sensor was productively smeared for the sensing of acetaminophen in human serum and pharmaceutical samples. The successful integration of graphene and metal NPs has attracted much attention due to their great surface area, improved the kinesis of charge carriers, and firm electron-transfer kinetics. Maduraiveeran et al. have designed an electrochemical β-nicotinamide adenine dinucleotide (NADH) sensor using unscrewed Au NP/rGO nanocomposite (Au-NPs/rGO) without using any redox mediators and enzymes

312

Handbook of Nanomaterials in Analytical Chemistry

Figure 12.7 SEM images of the rGO (A) and Au nanoparticle/rGO (B and C). Inset: photographs of rGO (A) and Au nanoparticle/rGO (B) films on Ti substrate. (C) EDS spectra obtained for rGO (bottom) and Au nanoparticle/rGO (top) films. The peaks marked with asterisks are derived from the Ti substrate. (D) XRD spectra of the rGO (bottom) and Au nanoparticle/rGO (top). Source: Reprinted from M. Govindhan, M. Amiri, A. Chen, Au nanoparticle/graphene nanocomposite as a platform for the sensitive detection of NADH in human urine, Biosens. Bioelectron. 66 (2015) 474 480 with permission from Elsevier.

[101]. The Au-NPs/rGO-based sensor (Fig. 12.7) exhibited superior electrocatalytic activity toward the oxidation of NADH in neutral solution by offering a suitable atmosphere for electron transfer through the boosted electrical conductivity. This sensor showed high sensitivity (0.916 μA μM21 cm2) and wide linear range (50.0 nM 500.0 μM) with a low detection limit of 1.13 nM (S/N 5 3). In addition, the developed sensor was tested for the detection of NADH in human urine samples, displaying the Au-NPs/rGO nanocomposite devise encouraging biomedical applications. Three-dimensional porous graphene (3D GN) is recently considered as new support for immobilization to improve the enzyme-like activities toward the sensing of various biomolecules. The structural effects of metal oxide nanomaterials such as NiO, Co3O4, and Fe3O4 and peroxidase-like activity were examined. Wang et al. recently fabricated 3D GN decorated with Fe3O4 NPs for the detection of glucose with a low sensing limit of 0.8 μM [102]. Graphene possesses significant advantages such as rich anchoring sites, extraordinary surface area, brilliant

Functional nanomaterial-derived electrochemical sensor

313

biocompatibility, and low-priced production cost in comparison to other kinds of carbon nanomaterials, including CNTs, fullerene, carbon dots, and nano-diamond. The functionalization of graphene sheets can be easily attained using numerous approaches such as mechanical mixing, hybridization, codeposition, covalent or noncovalent interaction, etc. The graphene-based nanomaterials have been used extensively in electrochemical sensors and biosensors for biomedical, healthcare, and clinical applications.

12.5

Polymer nanomaterials

Electrochemical sensor and biosensor platforms based on polymeric nanomaterials such as homo- and copolymers, polymeric structures with planned structure, and molecular shape-recognition materials have been used widely in the detection of biomolecules due to their facile functionalization of biomolecules and long-term stability [103 106]. The development of biomedical electrochemical sensor platforms trusts on manufacturing aspects of the biotic/abiotic interface. It has shown that electrochemical sensors and biosensors or biomedical devices comprise a physical, mechanical, or electrical transducer attached to a biorecognition element. The enhanced sensing performance of the polymer-based sensors can be simply attained via tuning the following factors: (1) biofunctionalization—it depends on the exposed surface and nature of biomolecules; (2) durability— covalent binding of the biomolecule; (3) increased electrochemical signal transduction—fast kinetics of carriers/analytes; and (4) high specificity—high recognition of bioanalytes. Owing to the high sensitivity, linearity, hysteresis, and selectivity, polymeric nanomaterials based on dendrimers, conducting polymers (CPs), and molecular-imprinted polymers (MIPs) have been used for the detection of DNA, enzymes, proteins, antigens, and metabolites. In this section, we highlight some recent examples of nanostructure functionalization, integration, and application of polymer nanomaterial-based electrochemical sensors and biosensors related to biomedical applications.

12.5.1 Dendrimers Dendrimer-based electrochemical sensor/biosensor platforms have been extensively engaged for the sensing various bioanalytes because of their unique structural properties, including structural consistency, veracity, well-ordered composition, and biocompatibility. Recently, significant efforts were made toward the preparation and utilization of dendrimer-based electrochemical sensing electrodes. In particular, a huge number of biosensors were established on the direct electrochemistry of hemeproteins and enzymes. The active biomolecules can easily be restrained on dendrimers without losing their biological activity that helps to produce efficient conducting interfaces useful in many fields. Dendrimers easily combine with a bulky number of bioreceptors because of their extraordinary quantity of amine

314

Handbook of Nanomaterials in Analytical Chemistry

groups, which significantly increase the sensitivity and detection limit of the target bioanalytes. Miodek et al. have developed a sensor for the detection of DNA using nanocomposite consisted of MWCNTs coated with polypyrrole (PPy) and redox poly(amidoamine) dendrimers (PAMAM) (MWCNTs-PPy-PAMAM) for Mycobacterium tuberculosis [107]. This sensor showed a low detection limit of 0.3 fM (S/N 5 3) with a linear range of 1 fM to 10 pM. Moreover, it was successfully applied to practical DNA samples from M. tuberculosis. The similar PAMAM-G4-based sensor was developed for the sensitive detection of paracetamol in commercially available tablets and human serum samples [108]. Voltammetry technique was used for the identifying of paracetamol using MWCNTs-PAMAM electrode and showed a low detection limit of 0.1 μM (S/N 5 3) with a linear range of 0.3 μM 0.2 mM. The CNT-functionalized dendrimer-based paracetamol sensor platform exhibited excellent permanence and specificity in presence of electrochemically active interferents.

12.5.2 Conducting polymers CPs have been successfully applied in wide-ranging uses such as chemical sensing, biosensing, gas sensing, supercapacitors, etc. due to their unique electronic properties. The nanostructured polypyrrole (PPy), polyaniline (PANI), polythiophene, and their functionalized derivatives thereof have been studied intensely for sensing and biosensing applications because of their intrinsic conductivity. The rapid development of biosensor system has also motivated to investigate the communication of these polymers with biological tissues through in vitro assays and methods to improve biocompatibility. Recently, Au-NPs patterned on polyaniline nanowires (PANI)-based electrochemical neurotransmitter sensor in presence of AA and UA were developed by Deveki and coworkers [109]. The deposition of Au-NPs improved the conductivity of the PANI-based hybrid system by offering significant electronic interactions with the polymer, thereby enhancing charge-transfer process. The developed sensor exhibited low detection limits of 0.08, 0.01, 0.025, and 0.04 μM for DA, AA, serotonin, and UA, respectively. Wang et al. have constructed a nonenzymatic blood glucose sensor using poly(o-phenylenediamine)/Ag-NPs (PoPD/Ag-NPs) composite [110]. The established glucose sensor disclosed a varied linear range of 0.15 13.0 mM with a low detection limit of 12.0 μM. The PoPD/ Ag-NPs electrode was stable for more than 10 weeks, showing great potential for bioanalysis. CP-based nanomaterials have been demonstrated to be decidedly well matched with an extensive diversity of live cells, and cell components owing to well-defined polymeric materials without dangling surface bonds, causing in an operative interaction with cells surface, enabling adhesion and promoting ionic interactions [111]. Recently, Liu et al. have designed a biosensor platform using cell membrane-mimic phosphorylcholine polymer film-enabled microelectrode for in vivo electrochemical detection of DA [112]. Fig. 12.8A shows the SEM images

Functional nanomaterial-derived electrochemical sensor

315

Figure 12.8 (A) SEM images obtained for bare CFE (a), PEDOT/CFE (b), PEDOT-OH/CFE (c), and PEDOT-PC/CFE (D). (B) Schematic representation of in vivo monitoring of dopamine (DA) using microelectrode. (C) Cyclic voltammertic (CV) curves recorded at PEDOT-OH/CFE (red curve) (a), PEDOT-PC/CFE (red curve) (b), and bare CFE (black curves in a and b) in a cerebrospinal fluid (CSF) containing 20 μM DA. (c) i t response toward 20 μM DA recorded with CFE (black) and PEDOT-PC/CFE (red). (d) i t response toward 20 μM DA recorded with CFE (black), PEDOT/CFE (blue), PEDOT-OH/CFE (green), and PEDOT-PC/CFE (red) upon the addition 10 mg mL21 bovine serum albumin (BSA). Source: Reprinted from X. Liu, T. Xiao, F. Wu, M.Y. Shen, M. Zhang, H.H. Yu, et al., Ultrathin cell-membrane-mimic phosphorylcholine polymer film coating enables large improvement for in vivo electrochemical detection, Angew. Chem. Inter. Ed. 56 (2017) 11802 11806 with permission from Wiley-VCH.

316

Handbook of Nanomaterials in Analytical Chemistry

of the developed electrodes, which have been used for in vivo electrochemical detection of DA in the biological living system (Fig. 12.8B). CF microelectrodes (CFEs) are entrenched into the animal’s brain, but unfortunately electrode-active materials in some cases perish by a nonspecific adsorption of biomacromolecules and proteins onto the microelectrode surface during in vivo electrochemical detection of biomolecules (Fig. 12.8C). The design of next-generation nanopolymer- or functionalized polymer-based devices with controlled surface structure and morphology is required to be investigated for improving selectivity and biocompatibility, which may further advance the sensing machineries to the extent of bioelectronics and healthcare.

12.5.3 Molecularly imprinted polymers MIP-based sensor and biosensor platforms have been used for a variety of target chemical and biological molecules. The imprinting of organic or biomolecules including pharmaceuticals, pesticides, amino acids, peptides, nucleotide bases, steroids and sugars, even metal and other ions are well demonstrated to favor the selective organization of functional groups in the imprinting network. It is still a challenging task for the imprinting of large or robust complex structures such as proteins through imprinting techniques. For the production of nanostructured MIPs, a variety of methods have been used such as suspension, dispersion, precipitation, and emulsion-seeded polymerization. Though the MIPs are normally organic solvent-compatible, the specific template binding of MIPs prepared in organic solvents is unusually decreased in aqueous environments, which dramatically limit the biotechnological applications. The combination of the self-assembly of an amphiphilic cross-linkable copolymer and imprinting technology is effectively used for a series of molecularly imprinted NPs in aqueous solution to fabricate several electrochemical sensors for biomedical application. Liu et al. have prepared a sensitive electrochemical paracetamol sensor using a water-dispersible molecularly imprinted electroactive NP by a combination of macromolecular self-assembly and molecular imprinting technique using paracetamol as a template molecule [113]. This sensor exhibited two linear ranges from 1.0 μM to 0.1 mM and 0.1 to 10 mM with a low detection limit of 0.3 μM for sensing of paracetamol. Li et al. have established a sensor for salbutamol based on Ag-NPs and N-doped rGO (Ag-N-rGO) [114]. The developed sensor showed an active catalytic property and outstanding discrimination toward the sensing salbutamol in human urine and pork samples. The Ag-N-rGO composite electrode presented a linear range of 0.03 20.00 μM with a low detection limit of 7.0 nM for sensing salbutamol. The Ag-N-rGO composite-based sensor not only enhances the sensitivity and selectivity of salbutamol, but also offers high stability and good reproducibility. Recently, Rao et al. have demonstrated an electrochemical creatinine sensor using of a magnetic-MIPs and a nanocomposite consisting of Ni-NPs

Functional nanomaterial-derived electrochemical sensor

317

and PANI (Ni@PANI-NPs) in urine-mimic and real-urine samples, which displayed a linear range from 40.0 to 800.0 nM with a low detection limit of 0.2 nM for sensing creatinine [115]. The combination of metal NPs into the MIP matrix permits to enrich the properties of inorganic NPs and polymer, providing excellent materials with novel functions suitable for biomedical fields. Indeed, multicomponent nanomaterials involving carbon nanomaterials (such as CNT, graphene), metal oxide nanomaterials (such as TiO2, Fe2O3), and noble metal NPs (such as Au, Ag, Pt, Pd) clearly provide distinct added advantages. The MIP-based science and technology has reached a new epoch where the molecular-recognition capability of the imprinted polymers and the implementation of nanostructures license designing/constructing exclusive biomimetic sensor devices with unprecedented analytical performances. The development polymeric nanomaterials such as dendrimers, conducting polymers, and molecular/ion-imprinted polymers were successfully established for biological and biomedical applications.

12.6

Bionanomaterials

Numerous efforts have been made on the development of novel biomaterials such as proteins/enzymes, nucleic acids, biopolymers, and their nanocomposite consisting of metal, semiconductor, carbon, and CPs for applications in biosensors, cell targeting, bioimaging, biomineralization, biocatalysts, and drug delivery because of their unique recognition, transport, electronic, and catalytic properties [116]. The combination of biotechnology and nanotechnology has directed the growth of nanocomposite materials, toward novel electrochemical biosensor platform incorporating highly selective catalytic and recognition properties of biomaterials, including proteins/enzymes, peptides, nucleic acids, and biopolymers. Over the past two decades, bionanomaterial-based electrochemical biosensor platforms have been successfully designed and attracted much attention due to their efficient sensing performances in terms of great sensitivity, selectivity, and biocompatibility. With the advancement in synthesis, functionalization, and integration of bionanomaterial, desired level of sensitivity and selectivity, rapid response, and speedy recovery can easily be achieved in the biological systems. A few selective biomaterial-based electrochemical sensor platforms for the detection of biomolecules are highlighted in the following section.

12.6.1 Aptamers Aptamer-based biosensors have much attention due to their high affinity, selectivity, and specificity, which are equal to or even superior to antibodies.

318

Handbook of Nanomaterials in Analytical Chemistry

Aptasensors have shown an excessive assurance in protein sensing with high sensitivity, selectivity, and low cost. Li et al. have developed a protein biosensor using a nanocomposite of CNTs, aptamer, and horseradish peroxidase [117] for thrombin with a sensing limit of 0.05 pM. The amperometric aptasensor based on various sensing substrates of nanocomposites such as ferrocene-aptamerCNTs, alkaline phosphatase-aptamer-SWCNTs, aptamer-Au-NPs-SWCNTs, and aptamer-MWCNTs-ionic liquid-CS have been established for thrombin detection. The microfluidic aptamer-based electrochemical biosensor for the detection of cardiac organoids was developed by Shin et al. [118]. Au-based microelectrode was functionalized with aptamers, which were highly selective to creatine kinase (CK)-MB (CK-MB) biomarker secreted from a damaged cardiac tissue. This biosensor was accessed to sense trace amounts of CK-MB secreted by the cardiac organoids upon drug treatments, agreeing well with the thrashing characteristics and cell feasibility scrutinizes. In recent years, the advancements in microfluidics provide new tactics to construct biomimetic human organoid models that mimic both the biology and the physiological microenvironment of the human system.

12.6.2 DNA nanostructures DNA triplex structure is very similar to the structure of aptamer, which has been used for the design of biosensors due to its high selectivity, low cost, simple synthesis, reusability, and high affinity and flexibility. For instance, Fu et al. have recently demonstrated a melamine biosensor based on DNA on an indium tin oxide electrode surface (Fig. 12.9A) [119]. This biosensor presented a low detection limit of 0.43 nM with a wide linear range from 1.0 nM to 0.5 μM (Fig. 12.9B and C). Deng et al. have demonstrated a dual signal-tagged hairpinstructured DNA (dhDNA)-based ratiometric probe using the combination of ferrocene-labeled signal probe (Fc-sP) and methylene blue-altered internal orientation probe (MB-rP) in one hairpin-structured DNA for the detection of Mucin 1 (MUC1) [120]. MUC1 is considered as a tumor marker model. This is very substantial for the initial diagnosis, distinguishing diagnosis, remedial consequence monitoring, and continuation inspections of patients with tumors or carcinomas. Hemaglutinin-based electrochemical biosensors such as genosensors and immunosensors were developed for biomedical applications. Recently, neuroaminidase enzyme activity assessment-based biosensor was designed for the detection of influenza A virus by Anik et al. [121]. Nanomaterial-based signal amplification, enzyme-based signal amplification, and DNA facilitating amplified sensor have been used to attain high sensitivity and selectivity. Electrochemical immunosensors based on functional nanomaterials are used for miniaturization of devices, making them suitable for POC diagnosis, DNA/enzyme amplification approach, and new electroanalytical techniques.

Functional nanomaterial-derived electrochemical sensor

319

Figure 12.9 Scheme for the melamine sensor based on DNA triplex structure and exo IIIassisted recycling amplification (A). DPV curves (B) and corresponding calibration plot (C) for sensing of melamine in the range of 1.0 nM—1.0 μM. Source: Reprinted from C. Fu, C. Liu, Y. Li, Y. Guo, F. Luo, P. Wang, et al., Homogeneous electrochemical biosensor for melamine based on DNA triplex structure and exonuclease IIIassisted recycling amplification, Anal. Chem. 20 (2016) 10176 10182 with permission from American Chemical Society.

12.7

Conclusion

This chapter describes the significance of functional nanomaterial-based electrochemical sensors and biosensors for majorly biomedical applications. The detailed electrochemical sensing and biosensing strategies based on wide range of functional nanomaterials such as noble nanomaterials, semiconducting metal oxide nanomaterials, carbon nanomaterials, polymeric nanomaterials, biomaterials, and their nanocomposites are described well in order as unique and amplified functionality toward

320

Handbook of Nanomaterials in Analytical Chemistry

electrochemical sensing and biosensing applications. The application of electrochemical sensor and biosensor platforms have been much attracted for in vivo and in vitro analyses relating a judiciously planned electrode/solution interface. As described in this chapter, diverse sensing nanomaterials are used to progress the electrochemical sensing and biosensing performance toward biomedical applications. An enormous research has been focused on the construction of nanocomposite-based electrodes consisting of noble metal NPs or metal oxides with carbon nanomaterials or polymer materials. The advanced nanocomposites favor the immobilization enzyme or bioactive molecules thereby enhancing the catalysis due to their synergistic effect. In certain noble metal NPs, especially Au NPs show intrinsic characteristics and played a key responsibility in designing sensitive biosensors. The advanced functional nanomaterial-based electrochemical sensing and biosensing platforms have potential for improving the scope of present neuroscience diagnostics, clinical, and point-of-care diagnostics.

Acknowledgments G.M. thanks DST-FIST (fund for improvement of S&T infrastructure) for financial assistance for Department of Chemistry, SRM Institute of Science and Technology, No. SR/FST/CST266/2015(c).

References [1] Z. Farka, T. Jurik, D. Kovar, L. Trnkova, P. Skladal, Nanoparticle-based immunochemical biosensors and assays: recent advances and challenges, Chem. Rev. 117 (2017) 9973 10042. [2] A. Piscitelli, A. Pennacchio, S. Longobardi, R. Velotta, P. Giardina, Vmh2 hydrophobin as a tool for the development of “self-immobilizing” enzymes for biosensing, Biotechnol. Bioeng. 114 (2017) 46 52. [3] G. Maduraiveeran, M. Sasidharan, V. Ganesan, Electrochemical sensor and biosensor platforms based on advanced nanomaterials for biological and biomedical applications, Biosens. Bioelectron. 103 (2018) 113 129. [4] X. Huang, Y. Liu, B. Yung, Y. Xiong, X. Chen, Nanotechnology-enhanced no-wash biosensors for in vitro diagnostics of cancer, ACS Nano 11 (2017) 5238 5292. [5] G. Rong, S.R. Corrie, H.A. Clark, In vivo biosensing: progress and perspectives, ACS Sens. 2 (2017) 327 338. [6] J. Kneipp, Interrogating cells, tissues, and live animals with new generations of surfaceenhanced raman scattering probes and labels, ACS Nano 11 (2017) 1136 1141. [7] D.L. Bowen Ren, Q. Jin, H. Cui, C. Wang, Novel porous tungsten carbides hybrids nanowires on carbon cloth for high-performance hydrogen evolution, J. Mater. Chem. A 5 (2017) 13196 13203.

Functional nanomaterial-derived electrochemical sensor

321

[8] F. Xiao, L. Wang, H. Duan, Nanomaterial based electrochemical sensors for in vitro detection of small molecule metabolites, Biotechnol. Adv. 34 (2016) 234 249. [9] C.M. Hussain, Handbook of Nanomaterials for Industrial Applications, Elseveir, 2018. ISBN: 9780128133514. [10] C.M. Hussain, Handbook of Nanomaterials in Chromatography: Current Trends in Chromatographic Research Technology and Techniques, Elsevier, 2018. ISBN: 9780128127933. [11] B.R. Smith, S.S. Gambhir, Nanomaterials for in vivo imaging, Chem. Rev. 117 (2017) 901 986. [12] G. Chen, I. Roy, C. Yang, P.N. Prasad, Nanochemistry and nanomedicine for nanoparticle-based diagnostics and therapy, Chem. Rev. 116 (2016) 2826 2885. [13] R.A. Masitas, S.L. Allen, F.P. Zamborini, Size-dependent electrophoretic deposition of catalytic gold nanoparticles, J. Am. Chem. Soc. 138 (2016) 15295 15298. [14] M. Qi, Y. Zhang, C. Cao, M. Zhang, S. Liu, G. Liu, Decoration of reduced graphene oxide nanosheets with aryldiazonium salts and gold nanoparticles toward a label-free amperometric immunosensor for detecting cytokine tumor necrosis factor-alpha in live cells, Anal. Chem. 88 (2016) 9614 9621. [15] S. Su, H. Sun, W. Cao, J. Chao, H. Peng, X. Zuo, et al., Dual-target electrochemical biosensing based on DNA structural switching on gold nanoparticle-decorated MoS2 nanosheets, ACS Appl. Mater. Interfaces 8 (2016) 6826 6833. [16] A. Gupta, D.F. Moyano, A. Parnsubsakul, A. Papadopoulos, L.S. Wang, R.F. Landis, et al., Ultrastable and biofunctionalizable gold nanoparticles, ACS Appl. Mater. Interfaces 8 (2016) 14096 14101. [17] Z. Chang, Y. Zhou, L. Hao, Y. Hao, X. Zhu, M. Xu, Simultaneous determination of dopamine and ascorbic acid using β-cyclodextrin/Au nanoparticles/graphene-modified electrodes, Anal. Methods 9 (2017) 664 671. [18] H. Rao, M. Chen, H. Ge, Z. Lu, X. Liu, P. Zou, et al., A novel electrochemical sensor based on Au@PANI composites film modified glassy carbon electrode binding molecular imprinting technique for the determination of melamine, Biosens. Bioelectron. 87 (2017) 1029 1035. [19] V. Baldim, A. Ismail, P. Taladriz-Blanco, S. Griveau, M.G. de Oliveira, F. Bedioui, Amperometric quantification of S-nitrosoglutathione using gold nanoparticles: a step toward determination of S-nitrosothiols in plasma, Anal. Chem. 88 (2016) 3115 3120. [20] P. Taladriz-Blanco, V. Pastoriza-Santos, J. Perez-Juste, P. Herves, Controllable nitric oxide release in the presence of gold nanoparticles, Langmuir 29 (2013) 8061 8069. [21] Y. Wang, L. Wang, H. Chen, X. Hu, S. Ma, Fabrication of highly sensitive and stable hydroxylamine electrochemical sensor based on gold nanoparticles and metalmetalloporphyrin framework modified electrode, ACS Appl. Mater. Interfaces 8 (2016) 18173 18181. [22] Y.P. Dong, Y. Zhou, J. Wang, J.J. Zhu, Electrogenerated chemiluminescence resonance energy transfer between Ru(bpy)321 electrogenerated chemiluminescence and gold nanoparticles/graphene oxide nanocomposites with graphene oxide as coreactant and its sensing application, Anal. Chem. 88 (2016) 5469 5475. [23] G. Maduraiveeran, R. Rasik, M. Sasidharan, W. Jin, Bimetallic gold-nickel nanoparticles as a sensitive amperometric sensing platform for acetaminophen in human serum, J. Electroanal. Chem. 808 (2018) 259 265.

322

Handbook of Nanomaterials in Analytical Chemistry

[24] U. Jain, N. Chauhan, Glycated hemoglobin detection with electrochemical sensing amplified by gold nanoparticles embedded N-doped graphene nanosheet, Biosens. Bioelectron. 89 (2017) 578 584. [25] A.M. Fekry, A new simple electrochemical moxifloxacin hydrochloride sensor built on carbon paste modified with silver nanoparticles, Biosens. Bioelectron. 87 (2017) 1065 1070. [26] I.J. Godfrey, A.J. Dent, I.P. Parkin, S. Maenosono, G. Sankar, Structure of gold silver nanoparticles, J. Phys. Chem. C 121 (2017) 1957 1963. [27] S. Kumar-Krishnan, A. Hernandez-Rangel, U. Pal, O. Ceballos-Sanchez, F.J. FloresRuiz, E. Prokhorov, et al., Surface functionalized halloysite nanotubes decorated with silver nanoparticles for enzyme immobilization and biosensing, J. Mater. Chem. B 4 (2016) 2553 2560. [28] G. Maduraiveeran, M. Kundu, M. Sasidharan, Electrochemical detection of hydrogen peroxide based on silver nanoparticles via amplified electron transfer process, J. Mater. Sci. 53 (2018) 8328 8338. [29] Y. Liu, X. Liu, Y. Liu, G. Liu, L. Ding, X. Lu, Construction of a highly sensitive nonenzymatic sensor for superoxide anion radical detection from living cells, Biosens. Bioelectron. 90 (2017) 39 45. [30] D. Martin-Yerga, E.C. Rama, A. Costa-Garcia, Electrochemical study and applications of selective electrodeposition of silver on quantum dots, Anal. Chem. 88 (2016) 3739 3746. [31] Q. Sheng, Y. Shen, J. Zhang, J. Zheng, Ni doped Ag@C core shell nanomaterials and their application in electrochemical H2O2 sensing, Anal. Methods 9 (2017) 163 169. [32] N. Yusoff, P. Rameshkumar, M.S. Mehmood, A. Pandikumar, H.W. Lee, N.M. Huang, Ternary nanohybrid of reduced graphene oxide-nafion@silver nanoparticles for boosting the sensor performance in non-enzymatic amperometric detection of hydrogen peroxide, Biosens. Bioelectron. 87 (2017) 1020 1028. [33] N.I. Ikhsan, P. Rameshkumar, N.M. Huang, Electrochemical properties of silver nanoparticle-supported reduced graphene oxide in nitric oxide oxidation and detection, RSC Adv. 6 (2016) 107141 107150. [34] Z.G. Liu, H. Forsyth, N. Khaper, A.C. Chen, Sensitive electrochemical detection of nitric oxide based on AuPt and reduced graphene oxide nanocomposites, Analyst 141 (2016) 4074 4083. [35] Y. Yan, J.Y. Zhang, L.X. Ren, C.B. Tang, Metal-containing and related polymers for biomedical applications, Chem. Soc. Rev. 45 (2016) 5232 5263. [36] A.C. Chen, S. Chatterjee, Nanomaterials based electrochemical sensors for biomedical applications, Chem. Soc. Rev. 42 (2013) 5425 5438. [37] X.P. Dang, H. Hu, S.F. Wang, S.S. Hu, Nanomaterials-based electrochemical sensors for nitric oxide, Microchim. Acta 182 (2015) 455 467. [38] D.J. Rao, Q.L. Sheng, J.B. Zheng, Novel nanocomposite of chitosan-protected platinum nanoparticles immobilized on nickel hydroxide: facile synthesis and application as glucose electrochemical sensor, J. Chem. Sci. 128 (2016) 1367 1375. [39] L.M. Zhang, J.L. Wang, Y. Tian, Electrochemical in-vivo sensors using nanomaterials made from carbon species, noble metals, or semiconductors, Microchim. Acta 181 (2014) 1471 1484. [40] R.Z. Zhang, W. Chen, Recent advances in graphene-based nanomaterials for fabricating electrochemical hydrogen peroxide sensors, Biosens. Bioelectron. 89 (2017) 249 268. [41] C.Z. Zhu, G.H. Yang, H. Li, D. Du, Y.H. Lin, Electrochemical sensors and biosensors based on nanomaterials and nanostructures, Anal. Chem. 87 (2015) 230 249.

Functional nanomaterial-derived electrochemical sensor

323

[42] V.V. Singh, K. Kaufmann, B.E.F. de Avila, E. Karshalev, J. Wang, Molybdenum disulfide-based tubular microengines: toward biomedical applications, Adv. Funct. Mater. 26 (2016) 6270 6278. [43] S. Imani, A.J. Bandodkar, A.M.V. Mohan, R. Kumar, S.F. Yu, J. Wang, et al., A wearable chemical-electrophysiological hybrid biosensing system for real-time health and fitness monitoring, Nat. Commun. 7 (2016) 11650. [44] A. Abella´n-Llobregat, I. Jeerapan, A. Bandodkar, L. Vidal, A. Canals, J. Wang, et al., A stretchable and screen-printed electrochemical sensor for glucose determination in human perspiration, Biosens. Bioelectron. 91 (2017) 885 891. [45] M. Parrilla, R. Canovas, F.J. Andrade, Paper-based enzymatic electrode with enhanced potentiometric response for monitoring glucose in biological fluids, Biosens. Bioelectron. 90 (2017) 110 116. [46] T. Maiyalagan, P. Kannan, M. Jonsson-Niedziolka, J. Niedziolka-Jonsson, Tungsten carbide nanotubes supported platinum nanoparticles as a potential sensing platform for oxalic acid, Anal. Chem. 86 (2014) 7849 7857. [47] M. Govindhan, Z.G. Liu, A.C. Chen, Design and electrochemical study of platinumbased nanomaterials for sensitive detection of nitric oxide in biomedical applications, Nanomaterials (Basel) 6 (2016) 211. [48] M.M. Shahid, P. Rameshkumar, A. Pandikumar, H.N. Lim, Y.H. Ng, N.M. Huang, An electrochemical sensing platform based on a reduced graphene oxide-cobalt oxide nanocube@platinum nanocomposite for nitric oxide detection, J. Mater. Chem. A 3 (2015) 14458 14468. [49] M. Govindhan, A. Chen, Enhanced electrochemical sensing of nitric oxide using a nanocomposite consisting of platinum-tungsten nanoparticles, reduced graphene oxide and an ionic liquid, Microchim. Acta 183 (2016) 2879 2887. [50] A.C. Chen, C. Ostrom, Palladium-based nanomaterials: synthesis and electrochemical applications, Chem. Rev. 115 (2015) 11999 12044. [51] F.H. Cincotto, D.L.C. Golinelli, S.A.S. Machado, F.C. Moraes, Electrochemical sensor based on reduced graphene oxide modified with palladium nanoparticles for determination of desipramine in urine samples, Sens. Actuat. B-Chem. 239 (2017) 488 493. [52] M.R. Majidi, S. Ghaderi, K. Asadpour-Zeynali, H. Dastangoo, Electrochemical determination of bromate in different types of flour and bread by a sensitive amperometric sensor based on palladium nanoparticles/graphene oxide nanosheets, Food Anal. Method 8 (2015) 2011 2019. [53] P. Kannan, J. Dolinska, T. Maiyalagan, M. Opallo, Facile and rapid synthesis of Pd nanodendrites for electrocatalysis and surface-enhanced Raman scattering applications, Nanoscale 6 (2014) 11169 11176. [54] A. Rahi, N. Sattarahmady, H. Heli, An ultrasensitive electrochemical genosensor for Brucella based on palladium nanoparticles, Anal. Biochem. 510 (2016) 11 17. [55] S. Shahrokhian, R. Salimian, S. Rastgar, Pd-Au nanoparticle decorated carbon nanotube as a sensing layer on the surface of glassy carbon electrode for electrochemical determination of ceftazidime, Mat. Sci. Eng. C-Mater. 34 (2014) 318 325. [56] B. Rezaei, L. Shams-Ghahfarokhi, E. Havakeshian, A.A. Ensafi, An electrochemical biosensor based on nanoporous stainless steel modified by gold and palladium nanoparticles for simultaneous determination of levodopa and uric acid, Talanta 158 (2016) 42 50. [57] H. Mao, J.C. Liang, H.F. Zhang, Q. Pei, D.L. Liu, S.Y. Wu, et al., Poly(ionic liquids) functionalized polypyrrole/graphene oxide nanosheets for electrochemical sensor to detect dopamine in the presence of ascorbic acid, Biosens. Bioelectron. 70 (2015) 289 298.

324

Handbook of Nanomaterials in Analytical Chemistry

[58] J. Li, Y. Wang, Y. Sun, C. Ding, Y. Lin, W. Sun, et al., A novel ionic liquid functionalized graphene oxide supported gold nanoparticle composite film for sensitive electrochemical detection of dopamine, RSC Adv. 7 (2017) 2315 2322. [59] C.H. Wang, C.H. Yang, J.K. Chang, High-selectivity electrochemical non-enzymatic sensors based on graphene/Pd nanocomposites functionalized with designated ionic liquids, Biosens. Bioelectron. 89 (2017) 483 488. [60] P. Kannan, T. Maiyalagan, E. Marsili, S. Ghosh, J. Niedziolka-Jonsson, M. JonssonNiedziolka, Hierarchical 3-dimensional nickel-iron nanosheet arrays on carbon fiber paper as a novel electrode for non-enzymatic glucose sensing, Nanoscale 8 (2016) 843 855. [61] K.C.F. Leung, S.H. Xuan, Noble metal-iron oxide hybrid nanomaterials: emerging applications, Chem. Rec. 16 (2016) 458 472. [62] V. Galstyan, E. Comini, I. Kholmanov, A. Ponzoni, V. Sberveglieri, N. Poli, et al., A composite structure based on reduced graphene oxide and metal oxide nanomaterials for chemical sensors, Beilstein J. Nanotech. 7 (2016) 1421 1427. [63] P.T. Gormley, N.I. Callaghan, T.J. MacCormack, C.A. Dieni, Assessment of the toxic potential of engineered metal oxide nanomaterials using an acellular model: citrated rat blood plasma, Toxicol. Mech. Method 26 (2016) 601 610. [64] S. Jahanbani, A. Benvidi, Comparison of two fabricated aptasensors based on modified carbon paste/oleic acid and magnetic bar carbon paste/Fe3O4@oleic acid nanoparticle electrodes for tetracycline detection, Biosens. Bioelectron. 85 (2016) 553 562. [65] L. Lan, Y. Yao, J. Ping, Y. Ying, Recent advances in nanomaterial-based biosensors for antibiotics detection, Biosens. Bioelectron. 91 (2017) 504 514. [66] Y. Xue, G. Maduraiveeran, M. Wang, S. Zheng, Y. Zhang, W. Jin, Hierarchical oxygen-implanted MoS2 nanoparticle decorated graphene for the non-enzymatic electrochemical sensing of hydrogen peroxide in alkaline media, Talanta 176 (2018) 397 405. [67] W. Alammari, M. Govindhan, A. Chen, Modification of TiO2 nanotubes with PtRu/graphene nanocomposites for enhanced oxygen reduction reaction, ChemElectroChem 2 (2015) 2041 2047. [68] M. Govindhan, T. Lafleur, B.-R. Adhikari, A. Chen, Electrochemical sensor based on carbon nanotubes for the simultaneous detection of phenolic pollutants, Electroanalysis 27 (2015) 902 909. [69] A. Mirzaei, K. Janghorban, B. Hashemi, G. Neri, Metal-core@metal oxide-shell nanomaterials for gas-sensing applications: a review, J. Nanopart. Res. 17 (2015) 371. [70] M.V. Bracamonte, M. Melchionna, A. Giuliani, L. Nasi, C. Tavagnacco, M. Prato, et al., H2O2 sensing enhancement by mutual integration of single walled carbon nanohorns with metal oxide catalysts: The CeO2 case, Sens. Actuat. B-Chem. 239 (2017) 923 932. [71] S. Yang, G. Li, D. Wang, Z. Qiao, L. Qu, Synthesis of nanoneedle-like copper oxide on N-doped reduced graphene oxide: a three-dimensional hybrid for nonenzymatic glucose sensor, Sens. Actuat. B-Chem. 238 (2017) 588 595. [72] O. Pecher, J. Carretero-Gonza´lez, K.J. Griffith, C.P. Grey, Materials’ Methods: NMR in Battery Research, Chem. Mater. 29 (2017) 213 242. [73] M. Yang, J.M. Jeong, K.G. Lee, D.H. Kim, S.J. Lee, B.G. Choi, Hierarchical porous microspheres of the Co3O4@graphene with enhanced electrocatalytic performance for electrochemical biosensors, Biosens. Bioelectron. 89 (2017) 612 619. [74] Q. Zhang, E. Uchaker, S.L. Candelaria, G. Cao, Nanomaterials for energy conversion and storage, Chem. Soc. Rev. 42 (2013) 3127 3171.

Functional nanomaterial-derived electrochemical sensor

325

[75] J.A. Albelda, A. Uzunoglu, G.N. Santos, L.A. Stanciu, Graphene-titanium dioxide nanocomposite based hypoxanthine sensor for assessment of meat freshness, Biosens. Bioelectron. 89 (2017) 518 524. [76] H. Zhu, L. Li, W. Zhou, Z. Shao, X. Chen, Advances in non-enzymatic glucose sensors based on metal oxides, J. Mater. Chem. B 4 (2016) 7333 7349. [77] N. Chauhan, S. Chawla, C.S. Pundir, U. Jain, An electrochemical sensor for detection of neurotransmitter-acetylcholine using metal nanoparticles, 2D material and conducting polymer modified electrode, Biosens. Bioelectron. 89 (2017) 377 383. [78] L. Han, C. Shao, B. Liang, A. Liu, Genetically engineered phage-templated MnO2 nanowires: synthesis and their application in electrochemical glucose biosensor operated at neutral pH condition, ACS Appl. Mater. Interfaces 8 (2016) 13768 13776. [79] A. Zhang, C.M. Lieber, Nano-bioelectronics, Chem. Rev. 116 (2016) 215 257. [80] O. Erol, I. Uyan, M. Hatip, C. Yilmaz, A.B. Tekinay, M.O. Guler, Recent advances in bioactive 1D and 2D carbon nanomaterials for biomedical applications, Nanomed. Nanotechnol. Biol. Med. 14 (2017) 2433 2454. [81] M. Kim, J. Jang, C. Cha, Carbon nanomaterials as versatile platforms for theranostic applications, Drug Discov. Today 22 (2017) 1430 1437. [82] N.L. Teradal, R. Jelinek, Carbon nanomaterials in biological studies and biomedicine, Adv. Healthc. Mater. 6 (2017) 1700574. [83] D. Jariwala, V.K. Sangwan, L.J. Lauhon, T.J. Marks, M.C. Hersam, Carbon nanomaterials for electronics, optoelectronics, photovoltaics, and sensing, Chem. Soc. Rev. 42 (2013) 2824 2860. [84] W.A. Marmisolle, O. Azzaroni, Recent developments in the layer-by-layer assembly of polyaniline and carbon nanomaterials for energy storage and sensing applications. From synthetic aspects to structural and functional characterization, Nanoscale 8 (2016) 9890 9918. [85] M.A. Ali, C. Singh, K. Mondal, S. Srivastava, A. Sharma, B.D. Malhotra, Mesoporous few-layer graphene platform for affinity biosensing application, ACS Appl. Mater. Interfaces 8 (2016) 7646 7656. [86] C. Yang, C.B. Jacobs, M.D. Nguyen, M. Ganesana, A.G. Zestos, I.N. Ivanov, et al., Carbon nanotubes grown on metal microelectrodes for the detection of dopamine, Anal. Chem. 88 (2016) 645 652. [87] L. Zhang, F. Liu, X. Sun, G.F. Wei, Y. Tian, Z.P. Liu, et al., Engineering carbon nanotube fiber for real-time quantification of ascorbic acid levels in a live rat model of alzheimer’s disease, Anal. Chem. 89 (2017) 1831 1837. [88] G. Baskaya, Y. Yildiz, A. Savk, T.O. Okyay, S. Eris, H. Sert, et al., Rapid, sensitive, and reusable detection of glucose by highly monodisperse nickel nanoparticles decorated functionalized multi-walled carbon nanotubes, Biosens. Bioelectron. 91 (2017) 728 733. [89] J. Bai, X. Zhang, Y. Peng, X. Hong, Y. Liu, S. Jiang, et al., Ultrasensitive sensing of diethylstilbestrol based on AuNPs/MWCNTs-CS composites coupling with sol-gel molecularly imprinted polymer as a recognition element of an electrochemical sensor, Sens. Actuat. B Chem. 238 (2017) 420 426. [90] M.M. Rahman, M.M. Hussain, A.M. Asiri, A glutathione biosensor based on a glassy carbon electrode modified with CdO nanoparticle-decorated carbon nanotubes in a nafion matrix, Microchim. Acta 183 (2016) 3255 3263. [91] M. Arvand, S. Hemmati, Magnetic nanoparticles embedded with graphene quantum dots and multiwalled carbon nanotubes as a sensing platform for electrochemical detection of progesterone, Sens. Actuat. B Chem. 238 (2017) 346 356.

326

Handbook of Nanomaterials in Analytical Chemistry

[92] M. Rahimi-Nasrabadi, A. Khoshroo, M. Mazloum-Ardakani, Electrochemical determination of diazepam in real samples based on fullerene-functionalized carbon nanotubes/ionic liquid nanocomposite, Sens. Actuat. B Chem. 240 (2017) 125 131. [93] V. Mani, M. Govindasamy, S.-M. Chen, R. Karthik, S.-T. Huang, Determination of dopamine using a glassy carbon electrode modified with a graphene and carbon nanotube hybrid decorated with molybdenum disulfide flowers, Microchim. Acta 183 (2016) 2267 2275. [94] E. Asadian, S. Shahrokhian, A. Iraji Zad, F. Ghorbani-Bidkorbeh, Glassy carbon electrode modified with 3D graphene carbon nanotube network for sensitive electrochemical determination of methotrexate, Sens. Actuat. B Chem. 239 (2017) 617 627. [95] Y. Li, J. Liu, M. Liu, F. Yu, L. Zhang, H. Tang, et al., Fabrication of ultra-sensitive and selective dopamine electrochemical sensor based on molecularly imprinted polymer modified graphene@carbon nanotube foam, Electrochem. Commun. 64 (2016) 42 45. [96] Z.H. Jin, Y.L. Liu, J.J. Chen, S.L. Cai, J.Q. Xu, W.H. Huang, Conductive polymercoated carbon nanotubes to construct stretchable and transparent electrochemical sensors, Anal. Chem. 89 (2017) 2032 2038. [97] X. Yu, W. Zhang, P. Zhang, Z. Su, Fabrication technologies and sensing applications of graphene-based composite films: advances and challenges, Biosens. Bioelectron. 89 (2017) 72 84. [98] C. Zhu, D. Du, Y. Lin, Graphene-like 2D nanomaterial-based biointerfaces for biosensing applications, Biosens. Bioelectron. 89 (2017) 43 55. [99] L. Wang, Y. Zhang, J. Yu, J. He, H. Yang, Y. Ye, et al., A green and simple strategy to prepare graphene foam-like three-dimensional porous carbon/Ni nanoparticles for glucose sensing, Sens. Actuat. B Chem. 239 (2017) 172 179. [100] B.-R. Adhikari, M. Govindhan, A. Chen, Sensitive detection of acetaminophen with Ggraphene-based electrochemical sensor, Electrochim. Acta 162 (2015) 198 204. [101] M. Govindhan, M. Amiri, A. Chen, Au nanoparticle/graphene nanocomposite as a platform for the sensitive detection of NADH in human urine, Biosens. Bioelectron. 66 (2015) 474 480. [102] Q. Wang, X. Zhang, L. Huang, Z. Zhang, S. Dong, One-pot synthesis of Fe3O4 nanoparticle loaded 3D porous graphene nanocomposites with enhanced nanozyme activity for glucose detection, ACS Appl. Mater. Interfaces 9 (2017) 7465 7471. [103] T.V. Duncan, K. Pillai, Release of engineered nanomaterials from polymer nanocomposites: diffusion, dissolution, and desorption, ACS Appl. Mater. Interfaces 7 (2015) 2 19. [104] O.I. Parisi, L. Scrivano, M.S. Sinicropi, N. Picci, F. Puoci, Engineered polymer-based nanomaterials for diagnostic, therapeutic and theranostic applications, Mini Rev. Med. Chem. 16 (2016) 754 761. [105] C.G. Qian, Y.L. Chen, P.J. Feng, X.Z. Xiao, M. Dong, J.C. Yu, et al., Conjugated polymer nanomaterials for theranostics, Acta Pharmacol. Sin. 38 (2017) 764 781. [106] H. Yoon, Current trends in sensors based on conducting polymer nanomaterials, Nanomaterials 3 (2013) 524 549. [107] A. Miodek, N. Mejri, M. Gomgnimbou, C. Sola, H. Korri-Youssoufi, E-DNA sensor of Mycobacterium tuberculosis based on electrochemical assembly of nanomaterials (MWCNTs/PPy/PAMAM), Anal. Chem. 87 (2015) 9257 9264. [108] Y. Zhang, X. Liu, L. Li, Z. Guo, Z. Xue, X. Lu, An electrochemical paracetamol sensor based on layer-by-layer covalent attachment of MWCNTs and a G4.0 PAMAM modified GCE, Anal. Methods 8 (2016) 2218 2225.

Functional nanomaterial-derived electrochemical sensor

327

[109] N.K. Sadanandhan, S.J. Devaki, Gold nanoparticle patterned on PANI nanowire modified transducer for the simultaneous determination of neurotransmitters in presence of ascorbic acid and uric acid, J. Appl. Pol. Sci. 134 (2017) 44351. [110] J. Wang, M. Wang, J. Guan, C. Wang, G. Wang, Construction of a non-enzymatic sensor based on the poly(o-phenylenediamine)/Ag-NPs composites for detecting glucose in blood, Mater. Sci. Eng. C Mater. Biol. Appl. 71 (2017) 844 851. [111] X. Strakosas, B. Wei, D.C. Martin, R.M. Owens, Biofunctionalization of polydioxythiophene derivatives for biomedical applications, J. Mater. Chem. B 4 (2016) 4952 4968. [112] X. Liu, T. Xiao, F. Wu, M.Y. Shen, M. Zhang, H.H. Yu, et al., Ultrathin cellmembrane-mimic phosphorylcholine polymer film coating enables large improvement for in vivo electrochemical detection, Angew. Chem. Inter. Ed., 56, 2017, pp. 11802 11806. [113] J. Luo, Q. Ma, W. Wei, Y. Zhu, R. Liu, X. Liu, Synthesis of water-dispersible molecularly imprinted electroactive nanoparticles for the sensitive and selective paracetamol detection, ACS Appl. Mater. Interfaces 8 (2016) 21028 21038. [114] J. Li, Z. Xu, M. Liu, P. Deng, S. Tang, J. Jiang, et al., Ag/N-doped reduced graphene oxide incorporated with molecularly imprinted polymer: an advanced electrochemical sensing platform for salbutamol determination, Biosens. Bioelectron. 90 (2017) 210 216. [115] H. Rao, Z. Lu, H. Ge, X. Liu, B. Chen, P. Zou, et al., Electrochemical creatinine sensor based on a glassy carbon electrode modified with a molecularly imprinted polymer and a Ni@polyaniline nanocomposite, Microchim. Acta 184 (2016) 261 269. [116] M.R. Saidur, A.R. Aziz, W.J. Basirun, Recent advances in DNA-based electrochemical biosensors for heavy metal ion detection: a review, Biosens. Bioelectron. 90 (2017) 125 139. [117] J. Li, J. Wang, X. Guo, Q. Zheng, J. Peng, H. Tang, et al., Carbon nanotubes labeled with aptamer and horseradish peroxidase as a probe for highly sensitive protein biosensing by post electropolymerization of insoluble precipitates on electrodes, Anal. Chem. 87 (2015) 7610 7617. [118] S.R. Shin, Y.S. Zhang, D.J. Kim, A. Manbohi, H. Avci, A. Silvestri, et al., Aptamerbased microfluidic electrochemical biosensor for monitoring cell-secreted trace cardiac biomarkers, Anal. Chem. 88 (2016) 10019 10027. [119] C. Fu, C. Liu, Y. Li, Y. Guo, F. Luo, P. Wang, et al., Homogeneous electrochemical biosensor for melamine based on DNA triplex structure and exonuclease III-assisted recycling amplification, Anal. Chem. 20 (2016) 10176 10182. [120] C. Deng, X. Pi, P. Qian, X. Chen, W. Wu, J. Xiang, High-performance ratiometric electrochemical method based on the combination of signal probe and inner reference probe in one hairpin-structured DNA, Anal. Chem. 89 (2017) 966 973. [121] U. Anik, Y. Tepeli, M.F. Diouani, Fabrication of electrochemical model influenza A virus biosensor based on the measurements of neuroaminidase enzyme activity, Anal. Chem. 88 (2016) 6151 6153.

Nanomaterial-based sensors

13

Fabiana Arduini1, Stefano Cinti2, Viviana Scognamiglio3 and Danila Moscone1 1 Department of Chemical Science and Technologies, University of Rome “Tor Vergata”, Rome, Italy, 2Department of Pharmacy, University of Naples “Federico II”, Rome, Italy, 3 Institute of Crystallography, Department of Chemical Sciences and Materials Technologies, Monterotondo Scalo, Rome, Italy

13.1

Introduction

Renaissance means new growth of activity or interest in something, especially art, literature, or music; nevertheless, we can stand this word in the science field as well. Among the multifarious branches of science, sensing is leading a renaissance era, thanks to the exploitation of cross-cutting technologies including nanotechnology, microfluidics and lab-on-chip, rational design, printing technology, and internet of things [1]. In particular, nanomaterials have been furnishing key instruments for easy engineering and fine-tuning unprecedented biosensing configurations based on recognition phenomena occurring at the nanoscale. Therefore, many nanomaterials have been widely exploited for the design of sensors and biosensors for several application fields. This established nanomaterial-based (bio)sensors as a hot topic, further confirmed by the fast growing of publications (Fig. 13.1). Nowadays, emerging nanomaterials are available for customizing both electrochemical and optical (bio)sensors, thanks to their fascinating properties as strong absorption band in the visible region, high electrical conductivity, and good mechanical features. Indeed, several nanomaterials are exploited with custom-made properties and controlled nanodimensions, including spheres and particles [metal nanoparticles (NPs), magnetic beads, and quantum dots (QDs)], nanotubes, nanowires, nanorods, nanofibers, as well as nanocomposites, nanofilms, nanopolymers, and nanoplates. A huge number of nanostructured (bio)sensors have been realized for many application fields exploiting different types of nanomaterials, including graphene, carbon nanotubes (CNTs), gold NPs (AuNPs), and nanomotors to name a few. Fig. 13.2 reports the trends of the last 10 years about the number of publications related to the use of the previously mentioned nanomaterials in the development of (bio)sensors, highlighting that graphene represents a rising star in the plethora of nanomaterials, while the use of CNTs remain almost constant. AuNPs have a slight Handbook of Nanomaterials in Analytical Chemistry. DOI: https://doi.org/10.1016/B978-0-12-816699-4.00013-X Copyright © 2020 Elsevier Inc. All rights reserved.

330

Handbook of Nanomaterials in Analytical Chemistry

Figure 13.1 Number of publications reported in Scopus with “nanomaterial and sensor” as keywords in the period 2010 18 (March 2019).

Figure 13.2 Number of publications reported in Scopus with “graphene/carbon nanotubes/ gold nanoparticles/nanomotors and sensor” as keywords in the period 2010 18. In case of nanomotors, the inset highlighted the low number of publications.

Nanomaterial-based sensors

331

increase, and nanomotors are relegated at a proof-of-concept level. These astonishing outcomes obtained by scientists exploiting graphene in many fields, including sensor technology, resulted in the largest research initiative in the European Union (UE) with the “Graphene Flagship”, tasked with taking graphene from laboratories into the market with a h1 billion budget [2]. If it is well established that nanomaterials entail inorganic materials, there is a new emerging vision, according to which biological materials as DNA and proteins can be considered as nanoscale entities being capable of folding in nanostructures [3 5]. As reported by Nature Nanotechnology journal “the ability of DNA to selfassemble into a variety of nanostructures and nanomachines is highlighted in a growing number of papers in Nature Nanotechnology. The appeal of DNA to nanoscientists is threefold: first, it is a natural nanoscale material; second, a large number of techniques for studying DNA are already available; and third, its ability to carry information can be exploited in the self-assembly process. DNA is also increasingly being used to organize other nanomaterials, and the related field of RNA nanotechnology is beginning to emerge” [6]. DNA is largely exploited as biological recognition elements (bioreceptors) in the design of biosensors, a branch of sensor technology. Beside DNA, enzymes are also used as biological recognition elements for catalytic detection as well as peptides and antibodies for affinity detection. In this scenario, it is noteworthy that the arrangement of nanomaterials and biological materials plays a crucial role in the design of hybrid nanostructured analytical devices “with enhanced detection performance in terms of response time, higher storage/operational stability, resistance toward environmental conditions, improved selectivity, reduced sample volumes, and easy sampling” [7].

13.2

Graphene

Graphene is a high-quality 2D crystal (one-atom-thick) with unique electronic properties, becoming an unlimited promise in the development of field-effect transistors, photovoltaic devices, and biosensors. The astonishing features of this nanomaterial were recently praised by K.S. Novoselov in his Nobel lecture (December 8, 2010), stating that graphene is “more than just a flat crystal”, which mimic massless relativistic particles, thanks to charge carriers. This crucial feature makes graphene a great candidate in the design of both electrochemical and optical (bio)sensors, being able: 1 to modify the electrochemical properties of an electrode and to work as label/loading agent for biomolecules and nanomaterials, thanks to its high surface area and easy functionalization, in the case of electrochemical transduction; 2 to provide fluorescence quenching at any wavelength by means of energy transfer in the case of optical transduction.

Therefore, depending on its multifarious configurations, graphene could be seen as a kaleidoscope in the realization of sensing tools with uncountable shapes, as largely described in the following subchapters.

332

Handbook of Nanomaterials in Analytical Chemistry

13.2.1 Electrochemical graphene-based (bio)sensors As a matter of fact, graphene is an excellent transducer material in biosensors, thanks to its propriety of high electron transfer and specific surface area. Graphenemodified screen-printed electrodes (SPEs) found applicable in many analytical sectors for revealing compounds ranging from clinical diagnosis to environmental pollution. Various graphene forms are available with graphene oxide (GO) and reduced graphene oxide (rGO) as the most used, or composites in combination with ZnO nanorods, CNTs, AuNPs, polyaniline, and pyrrole, just to name a few. Graphene oxide nanosheets (GONs) were recently exploited as an SPE modifier in combination with titanium dioxide nanofibers (TNFs) to detect adenine by differential-pulse voltammetry (DPV) [8]. The authors underlined that the synergistic effect between GONs and TNFs, with an occurred decrease of overpotential and an increase of the peak current, resulted in a detection limit of 1.71 nM within two linear ranges (0.1 1 and 1 10 μM) in the presence of guanine as interferent. rGO was also used as a network between ions and the electrode to design a disposable ion-selective electrode to selectively detect calcium [9]. In this case, the high graphene hydrophobicity prevented the formation of an aqueous layer inside the electrode avoiding drift instability, displaying a potential drift of only 14.7 μV h21 during continuous monitoring (20 h). This electrode (Fig. 13.3A) exhibited a Nernstian slope of 29.1 mV/decade, a linearity range of 1025.6 to 1021.6 M of Ca21 and a detection limit of 1025.8 M. The same research group deposited rGO by one-step electrodeposition of the exfoliated GO sheets onto an ionic liquid-doped SPE for the detection of glucose by using glucose oxidase [11]. This graphene-modified electrode demonstrated the ability to reveal the enzymatic product hydrogen peroxide at a negative applied potential (20.2 V vs Ag/AgCl) within a linear range from 0.15 μM to 1.8 mM. Therefore, glucose was detected with a sensitivity of 22.78 μA mM21 cm22 and a detection limit of 1.0 μM, within a linear range up to 10 mM. The suitability of the biosensor was challenged in milk samples with satisfactory recovery values, demonstrating its aptness for glucose determination in real samples. GO was similarly used in combination with ultrathin Au nanowires to modify SPEs for the development of an innovative 3D paper-based immunosensor to detect the tumor marker α-fetoprotein [10]. The presence of α-fetoprotein as low as 0.5 pg mL21 was evaluated by adding CuS nanoparticle-decorated graphene (CuS/ GO) composites used as label of the signal antibodies, showing efficient electrocatalytic activity toward the reduction of H2O2 (Fig. 13.3B). In this work, graphene demonstrated to be able to augment the electrochemical performances of the SPE, as well as the antibody loading. GO nanoplatelets electroactive properties were also recognized in a DNA electrochemical sensor for single-nucleotide polymorphism detection, based on the interactions between GO nanoplatelets and DNA strands [12]. The sensing mechanism was based on the different binding ability of single-stranded (ss) and doublestranded (ds) DNA toward GO nanoplatelets and the stronger ability of graphene to conjugate ssDNA with respect to dsDNA, demonstrating the inherently

Nanomaterial-based sensors

333

Figure 13.3 (A) Ion-selective electrochemical sensor using graphene as the ion-to-electron transducer for calcium detection [9]. (B) Immunosensor for α-fetoprotein measurement designed by immobilizing the capture antibody onto the working electrode surface, previously modified by drop-casting GO and ultrathin gold nanowires. The binding with α-fetoprotein was evaluated by adding CuS nanoparticle-decorated graphene (CuS/GO) composites labeled to the signal antibodies [10].

electroactive property of GO. In this way, the detection at SPE of a noncomplementary target yielded a higher voltammetric signal than the complementary target at an SPE, because higher amounts of graphene were confined on the working electrode surface in the case of ssDNA.

13.2.2 Optical graphene-based biosensors As aforementioned, graphene derivatives show multifarious characteristics, which can be exploited for the design of optical (bio)sensing systems, including the ability of fluorescence quenching at any wavelength by means of energy transfer. It is a matter of fact that the efficiency of this ability depends on the number of graphene layers as well as from their oxidation degree. The most used in optical (bio)sensors are oxidized graphene derivatives, which undergo a recombination of electron hole pairs localized within an sp2 carbon domain embedded within an sp3 matrix, thus

334

Handbook of Nanomaterials in Analytical Chemistry

resulting in characteristic photoluminescent properties. Indeed, it is possible to modulate the maximum fluorescence emission wavelength from the blue region to the near-infrared region by simply tuning the oxygen-containing moieties, the lateral size, and the oxidation degree [13]. These amazing features allowed to custom-make strategic DNA-based sensing principles based on effective interactions (hydrophobic and π π stacking interactions) between the hexagonal cells of graphene derivatives and the ring structures in nucleotides. The sensing mechanism of such biosensors is certainly elegant: an ssDNA labeled with a fluorescent probe is complexed with the graphene derivative, thus resulting in a quenched state when the analyte is absent. In the presence of the target analyte, the ssDNA/graphene complex is detached, hence recovering its fluorescence, as more weaker interactions between graphene and the nucleotide rigid structure occur (Fig. 13.4A) [14]. Different graphene derivatives have been exploited to set-up such sensing configurations, with graphene QDs and GO as the most common [13]. Morales-Narva´ez

Figure 13.4 (A) Scheme of graphene-based nanomaterials as a DNA biosensor with fluorescent detection [14]. (B) Scheme of strategy for a microRNA sensor based on graphene oxide (GO) and peptide nucleic acids (PNAs) for multiplexed microRNA sensing in vitro. The fluorescence signal is recovered when the fluorescent dye-labeled probes, initially adsorbed onto the surface of GO, detach from it and hybridize with a target microRNA [15].

Nanomaterial-based sensors

335

and coworkers used antibody/QD (Ab-QD) probes and GO to design a pathogen-detection microarray [16]. This sensing principle is based on the energy-transfer phenomenon that occurs between photoexcited QDs and GO when in close proximity. In the absence of the pathogen, the Ab-QD probes extensively interact through π π stacking with GO, which quenches their fluorescence. When the pathogens are selectively captured by the Ab-QD probes, they fluoresce when excited with a laser, since a weaker interaction occurs with GO that, in this configuration, is not more capable of strong fluorescence quenching. As a model pathogen to test the system, Escherichia coli O157:H7.16 was used, while QDs were (core-shell) CdSe@ZnS QDs functionalized with streptavidin. This biosensing approach led to a highly specific and sensitive analysis, noticeable up to 10 CFU mL21 in standard buffer and 100 CFU mL21 in bottled water and milk. Ryoo and coworkers [15] described the use of GO for the development of an optical biosensor to detect microRNAs exploiting peptide nuclei acids (PNA), highlighting the advantages of graphene as high loading capacity nanomaterial for bioreceptor immobilization. In particular, GO was used both as scaffold for peptide nucleic acid and as a quencher for the fluorophore attached to the PNA probe (Fig. 13.4B). After the addition of the target, the labeled PNA was able to emit fluorescence in a concentration-dependent manner monitoring target microRNAs in the picomolar range.

13.3

Carbon nanotubes

In 1991, a letter of Iijima was published on Nature, reporting the synthesis of nanometer-size and needle-like tubes of carbon, namely helical microtubules of graphitic carbon, that now we call CNTs. CNTs came across notable interest in chemistry, physics, and material science since their discovery in 1991, own to their 1D structure and unique properties [17]. These tubular structures are composed by sp2 carbon units and can stand principally as single-walled CNTs (SWCNTs) and multiwalled CNTs (MWCNTs). Many research articles have been published entailing CNTs for several applications such as microelectronic circuitry, biological systems, and sensing devices also coupled with other nanomaterials, compounds, or/and biocomponents [18].

13.3.1 Electrochemical carbon nanotube-based (bio)sensors The copious features of CNTs, as the electrocatalytic properties own to edge defect sites and metal impurities, combined with the high surface area, suitable to immobilize nanomaterials and/or biocomponents, have been widely exploited to develop electrochemical (bio)sensors. Indeed, in the years comprised between 1991 and 2010, CNTs played a noticeable role in sensor design, afterward losing their leading position because tarnished by graphene. As mentioned above, CNTs were principally used in combination with other nanomaterials, as in the case of Dong et al. [19], which developed a glassy carbon

336

Handbook of Nanomaterials in Analytical Chemistry

electrode modified with a nanocomposite constituted of MWCNTs CeO2 Au NPs for methyl parathion detection, with a limit of 3.02 3 10211 M. This nanocomposite was able to perform the solid-phase extraction of the herbicide, thanks to the exceptional adsorption properties of MWCNTs, resulting in high sensitivity. Moreover, because of the presence of CeO2 and AuNPs, a high surface area and a special catalytic activity were provided, with a great sensitivity improvement when methyl parathion was detected in river and soil samples. MWCNTs were also joined with GO sheets by Huang et al. [20] to release an interesting hybrid nanocomposite used to modify glassy carbon electrodes for the detection of Pb21 and Cd21 with a detection limit of 0.2 and 0.1 μg L21, respectively (Fig. 13.5A). This nanocomposite was characterized by an excellent conductivity and a good water-solubility, overcoming respective deficiencies, since the hydrophilic GO sheets could load CNTs through π π stacking interactions, overcoming the solubility problem, while the presence of CNTs suppresses the aggregation between GONs. CNTs also showed high capability for bioreceptor immobilization, enhancing the biomolecule loading as well as the electrochemical analytical performances, as demonstrated by Vicentini et al. [21]. The authors immobilized tyrosinase enzyme on CNTs using their carboxylic moieties. In detail, tyrosinase was covalently immobilized onto CNTs by means of (1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide) and N-hydroxysuccinimide, for catechol detection with a detection limit of 0.58 μM (Fig. 13.2B).

13.3.2 Optical carbon nanotube-based (bio)sensors The brilliant exclusive optical features of CNTs have gained huge attention among researchers in the development of optical biosensors for the detection of several analytes of biomedical and agro-environmental interest. Indeed, such nanomaterials possess peculiar characteristics that can be tuned for the different optical transductions, including luminescence, fluorescence, and color changes, as well as extended wavelength range of emission from 700 to 1400 nm, high photostability, low autofluorescence, and deep penetration capability in skin for in vivo imaging among others [22]. CNTs are rolled-up cylinders of carbon monolayers (graphene), which can be chemically custom-made in such a way that bioreceptors can be accommodated in ideal environments to enhance their robustness as well as their sensitivity and selectivity toward target molecules [23]. The most important optical sensing mechanisms exploiting CNTs are: 1. Fluorescence: change of the fluorescence spectrum due to the interaction between analyte and SWCNT/wrapping (intensity or wavelength shift); 2. Quenching: proximity quenching of other (organic) fluorophores; and 3. Raman scattering: CNTs are used as a tag exhibiting extremely high Raman scattering.

Several biosensors using CNTs have been described in the literature toward different target analytes from DNA [24] to oxygen reactive species [25], hydrogen

Nanomaterial-based sensors

337

Figure 13.5 (A) Scheme of GO and MWCNTs nanocomposite and its application for heavy metal detection [20]. (B) Scheme of the reaction used to immobilize tyrosinase enzyme on MWCNT [21].

peroxide [26], nitric oxide [27], proteins [28], and small molecules as ATP [29]. Many CNT-based biosensors have been also setup for glucose monitoring in diabetic patients because of CNTs high suitability in the design of continuous implantable diagnostic tools where high sensitivity, tissue transparency, and no

338

Handbook of Nanomaterials in Analytical Chemistry

photobleaching are required. Yoon et al. [30] covalently conjugated the periplasmic glucose-binding protein from E. coli with carboxylated poly(vinyl alcohol)wrapped SWNTs, leading to allosterically controlled optical transduction by reversible exciton quenching in response to glucose. Glucose-binding protein is characterized by two domains linked by a “hinge” region; it binds the sugar with very high specificity undergoing a conformational change in which the two domains close around the glucose. This actuation resulted in changes of the polymer SWCNT interaction, ultimately causing a highly selective and reversible SWCNT fluorescent quenching, proportional to the glucose concentration. Changes in fluorescence emission of glucose-binding protein/SWNTs were analyzed at different glucose concentrations, over a long observation time ( . 60 h), thanks to the photostability of SWNT. A similar approach was exploited by Ahn et al. to study the interaction mechanisms among proteins [31]. In detail, they used CNTs as optical sensors for the label-free detection of protein protein interactions where each nanotube was encased within a chitosan polymer wrapping modified with nitrilotriacetic acid moieties (Fig. 13.6). After Ni21 chelation, NTA Ni21 complexes work as proximity quenchers, modulating the intrinsic SWCNT fluorescence intensity as a function of distance from the SWCNT surface. The Ni21 NTA group binds to any capture protein, which possesses a hexahistidine tag. Upon target binding to the capture protein, a variation of Ni21-SWCNT distance occurred, allowing for the evaluation of protein binding by means of fluorescence intensity changes.

Figure 13.6 Schematic of the SWCNT array and the signal transduction. NTA-bound Ni21 ions act as proximity quenchers of the nanotube fluorescence. Upon binding of a histagged capture protein, the distance of the ion from the SWCNT surface decreases, resulting in a fluorescence-quenching response. Upon binding of an analyte protein to the his-tagged capture protein, a further fluorescence modulation occurs, allowing for direct detection of the binding event [31].

Nanomaterial-based sensors

339

As evidenced, obvious advantages of CNTs make them suitable candidate in the design of optical biosensors. Among others, CNTs’ different chiralities allow to configure multiplexing platform since every SWCNT could be used as a single color. However, this diversity can also be considered as a concern, since so far ensembles of different chiralities, length, and impurities might decrease sensitivity and selectivity. The lower fluorescence quantum yield can be also considered a drawback if compared with high quantum yield fluorophores, as for example QDs; thus many other nanomaterials are gaining much attention in the last years, as a replacement to CNTs.

13.4

Other carbon-based materials

It is noteworthy that the properties of one and two-dimensional (2D) graphitic materials, such as CNTs, graphene, and other carbon nanomaterial as carbon nanofibers (CNFs) have received increased attention due to their physical and chemical properties not available in other materials, such an interesting molecular structure, high surface area for bioreceptor loading, size-tunable emission, narrow and symmetric photoluminescence, broad and strong excitation spectra, strong luminescence, and robust photostability. Thanks to these fascinating properties, these carbon nanostructures have been extensively used for the development of electrochemical and optical (bio)sensors.

13.4.1 Other carbon-based materials in electrochemical biosensors Among the most famous carbon-based materials namely graphene and CNTs, carbon black (CB) is a carbon nanomaterial that has recently attracted a huge attention by scientists thanks to its cost-effectiveness as well as outstanding electrochemical properties. Before 2010, few articles have been reported for the application of CB as electrode modifier for analyte detection in solution. Only after 2010 there was a relevant growth of publication number describing CB as electrode nanomodifier. Our group highlighted the mesmerizing electrochemical characteristics of CB in the ink/paste as well as in modifying electrodes by drop-casting to reveal many analytes as catechol, hydrogen peroxide, nicotinamide adenine dinucleotide (NADH), and thiocholine [32 35]. Our results were validated by other groups: Compton’s group [36] reported the gain of using CB over the more specialized MWCNTs in terms of sensitivity toward the detection of nicotine by adsorbitive stripping voltammetry, because the presence of CB allowed higher current responses for nicotine oxidation at lower potentials. Pumera’s group [37] demonstrated that CB is more suitable than the thermally reduced GO, being cheaper and not requiring any chemical and physical treatment before use. Fatibello-Filho’s group [38] as well as Evtugyn’s group [39] successfully used CB-modified electrodes for the detection of different analytes. Arduini et al. [35] reported a miniaturized and disposable

340

Handbook of Nanomaterials in Analytical Chemistry

electrochemical sensor for phenolic compound detection constructed by modifying the working electrode surface of SPEs with CB dispersion (Fig. 13.7A). This sensor showed higher sensitivity and better resistance to fouling than the bare SPE, displaying the suitability of CB as an excellent electrode nanomodifier. Catechol, gallic acid, caffeic acid, and tyrosol were detected by square-wave voltammetry with detection limits of 0.1, 1, 0.8, and 2 μM, respectively. Other recently used nanomaterials with peculiar features are magnetic carbon structures, starting from spheres (CSs) to more elongated structures as tubes and fibers, with nano- and microsize. Arduini and colleagues [40] combined CSs with SPEs highlighting their electrochemical effectiveness toward the detection of several species, that is, ferricyanide, ascorbic acid, dopamine, cysteine, serotonin, and NADH (Fig. 13.7B). The presence of iron nuclei within the carbonaceous lattices, besides improving the electrochemical performances of the printed electrodes, might confer these CS-based structures a future application in the field of remediation/sensing. In addition, this magnetic material was used for collecting the sample (e.g., ferricyanide) and measuring it on the working electrode surface by cyclic voltammetry.

13.4.2 Other carbon-based materials in optical biosensors Many optical biosensors entail fluorescence transduction based on Fo¨rster resonance energy transfer (FRET), which consists in the transfer of energy from a photoexcited energy donor to a close energy acceptor. To this aim, carbon nanomaterials are good candidates for biosensor configuration as smart quenchers. Morales-Narva´ez and coworkers [41] explored the ability of different carbon nanomaterials as quencher in comparison with the most used QDs for FRET measurements. In this regard, the authors exploited QDs as donors and graphite, CNTs, CNFs, and GO as energy acceptors of FRET from QDs. The responses of the explored carbon-based materials as acceptors of QD FRET donors in the proposed platform are displayed in Fig. 13.8. They observed that graphite was a weak acceptor for spots deposited from high concentration suspensions (0.5 1 mg mL21), while for thinner films at graphite lower concentrations (0.125 0.25 mg mL21), graphite becomes a strong acceptor. Both CNT and CNF in general behave as stronger acceptors in comparison to graphite, whereas, as observed, the strongest quenching is caused by GO at all the studied concentration values (from 0.125 to 1 mg GO mL21). A recent example of optical biosensor based on carbon nanomaterials was described by Wang and colleagues for the detection of thrombin by exploiting aptamers and FRET [42]. In detail, poly(acrylic acid) functionalized upconverting phosphors were covalently tagged with a thrombin aptamer, bound to the surface of carbon NPs through π π stacking interaction. The energy donor and acceptor were taken into close proximity, providing quenching of upconverting phosphors. The presence of thrombin allowed for quadruplex structure of the aptamer resulting in the increasing of the distance between acceptor and donor, blocking the FRET process, restoring the fluorescence in a thrombin concentration-dependent manner.

Figure 13.7 (A) Square-wave voltammetry using bare SPE (blue line) and SPE modified with CB (black line) in absence (dashed line) and in the presence of different concentrations (continuous line) of catechol, caffeic acid, gallic acid, and tyrosol [35]. (B) Schematic representation of the experimental path followed to collect ferricyanide on the aggregate CSs and release the same molecule on a printed electrode, that is, SPE. Electrochemical detection by using a bare SPE without CSs aggregate (black line) and in presence of 1 mg of CSs aggregate immersed for 10 (red line), and 30 (green line) min in a 3-mL solution containing 10 mM ferricyanide [40].

342

Handbook of Nanomaterials in Analytical Chemistry

Figure 13.8 Responses of four carbon-based materials as acceptors of QDs FRET donors in the solid phase and their UV Vis spectra. Graphs show fluorescent intensity profile of the spots. (A) Unquenched QDs (blank). (B) QD quenching by graphite. (C) QD quenching by carbon nanotubes (CNTs). (D) QD quenching by carbon nanofibers (CNFs). (E) QD quenching by graphene oxide (GO). Carbon-based material concentration: 1, 0.5, 0.25, 0.125 mg mL21 in dimethylformamide (DMF) (from left to right respectively). QD concentration: 12.5 nM in PBS. (F) UV Vis absorbance of the studied carbon materials and QD emission (excitation wavelength, 630 nm) [41].

The sensor provided a linear range from 0.5 to 20 nM for thrombin with a detection limit of 0.18 nM in an aqueous buffer.

13.5

Non-carbonaceous nanomaterials

Beyond the use of carbonaceous-based entities such as graphene, nanotubes, CB, fullerene, etc., creating nanostructures starting from noble metals has been widely adopted in producing both electrochemical and colorimetric sensing platforms. However, many other nanomaterials can improve the performance of sensing devices such as inorganic crystals, oxides, and semiconductors, which can be

Nanomaterial-based sensors

343

synthesized at nanosized level to reveal their tremendous enhancement of proprieties while detecting traces of analytes in complex matrices such as surface waters, blood, urine. Prior to analyzing the various applications related to the use of nanomaterials, it should be noted that many of them can be used in a ubiquitous way. For example, AuNPs can be used for the development of colorimetric assays due to their size-dependent plasmonic band and also for the realization of electrochemical platforms by exploiting their high surface area and electrocatalysis [43]. In next section, some of the successful applications of these nanosized boosters are reported.

13.5.1 Non-carbonaceous nanomaterials electrochemical (bio)sensors 13.5.1.1 AuNPs Recently, AuNPs have been used to develop screen-printed paper strips for the electrochemical detection of ss- and ds-DNA sequences related HIV in serum samples [44], as shown in Fig. 13.9A. In this work, two kind of paper-based substrates, namely filter and copy papers, have been evaluated toward the realization of an affordable device capable to detect targets in few microliters of undiluted serum samples. The AuNPs have been obtained by making an Au precursor salt reacting with a reductant (sodium borohydride) and a capping agent (sodium citrate). However, it should be considered that the synthesis of the final B20 nm NPs needed very clean glassware (in fact, aqua regia and piranha solution have been used for cleaning). The role of AuNPs was dual: they served as anchor points for the attachment of the thiol-extremity of the DNA probe, and they produced an obvious improvement of the electrochemical properties compared to unmodified graphite-based printed electrodes. AuNPs allowed, at a very low cost of production, to reach detection limit of 3 and 7 nM, respectively, for ss and ds sequences. In comparison with the classical approaches, that involve the use of Au macroelectrode, the use of AuNPs for DNA sensing is highly recommendable especially in terms of surface-to-volume ratio. The use of AuNPs has been also adopted for the analysis of heavy metals in environmental context such as the detection of arsenic in surface waters [47] and mercury in soil [48]. Clear advantages must be attributed to the combined presence of AuNPs and CB. The latter allowed increasing the spreading of AuNPs on the top of the SPE area, thus augmenting the available area for detecting the metals. Arsenic and mercury have been detected, respectively, down to 0.4 and 3 ppb as detection limits. The extremely high portability of the platforms permitted to carry out the measurements directly on-site, reducing costs and time-consuming procedures of laboratory-based settings. However, the use of AuNPs should not only be linked to the modification of the electrode’s surface. In fact, AuNPs can also be applied as electrochemical label. The group of Merkoc¸i developed a new methodology for the isothermal amplification of Leishmania DNA using magnetic beads coupled to AuNPs [49]. The

344

Handbook of Nanomaterials in Analytical Chemistry

Figure 13.9 (A) Schematic representation of the paper-based E-DNA platform for the detection of single- and double-stranded DNA targets. The measurements have been carried out with a multi-8 reader, by using one-shot SPE for each concentration of target [44]. (B) TEM micrographs of AuAg NSs composed, SEM of AuAg NSs surface characterization, comparison of differential-pulsed voltammetries (DPVs) of AuAg NSs in different buffers. In the absence of chlorides in the matrix, no Ag corrosion is possible and therefore no stripping detection can be carried out (Permission from [7]); (C) Preparation of GCE and fabrication of modified GCE with CuNPs-multiwalled carbon nanotubes-reduced GO [45]. (D) Development and measurement scheme of the blood glucose biosensor on paper Blue. Amperometric detection of increasing concentration of glucose (0 30 mM), applying 20.1 V. Inset: calibration curve of glucose in the range 0 30 mM (measurements have been carried out in 0.05 M phosphate buffer, pH 7.4); Paper Blue versus Bayer Contour for blood glucose determination [46].

presence of magnetic beads allowed to purificate/concentrate the analyte, while AuNPs were used both to label the oligonucleotide primers and to enhance the electrochemical signal for the rapid quantification of the DNA on screen-printed carbon electrodes. The presence of AuNPs displayed an electroactive role toward the hydrogen evolution reaction after the addition of acid, and this strategy yielded the quantification of less than one parasite per microliter of blood. The adoption of this inorganic label allowed to achieve a good stability in terms of shelf-life of the primer/AuNPs adduct, that in fact arrived up to 8 weeks when stored at 4 C and in dark condition.

Nanomaterial-based sensors

345

13.5.1.2 AgNPs Although the use of AuNPs for the development of electrochemical platforms represents the majorly adopted choice, AgNPs are also used for the realization of sensors and biosensors. However, due to the susceptibility of Ag to be oxidized in presence of halide ions when a slightly positive potential is applied, especially in presence of chloride, its application as an electrode modifier does not represent the first choice because its oxidation might hide the peak corresponding to the species of interest. On the contrary, the use of AgNPs is particularly effective when an electrochemical label is needed. Many examples are reported within the field of electrochemistry. For instance, AgNPs together with graphene have been used to develop a novel trace label for the development of a clinical immunosensor for avian influenza virus H7 [50]. In order to produce a stable adduct, a chitosan solution has been added to provide carboxylic groups (after NaOH treatment) for the conjugation with H7polyclonal antibodies, making a biohybrid conjugate. Taking advantage of the high surface-to-volume ratio of graphene, a high amount of AgNPs has been immobilized, and allowed to improve the sensitivity of the final platform by detecting the virus with a detection limit of 1.6 pg mL21 and a four-orders linearity range (up to 16 ng mL21). In addition, the bioconjugate retained more than 90% of its initial activity after a storage period of 1 month in phosphate-buffered saline solution. Beyond this, the use of AgNPs as electrochemical label has been recently demonstrated in combination with Au. Russo et al. [51] took advantage of a novel class of nanomaterial, namely hollow AuAg nanoshells (NSs), to detect E. coli and Salmonella typhimurium at a screen-printed carbon-based electrode. The determination of bacteria is due to non-specific affinity interactions between bacteria’s walls and AuAg NSs surface. The electrochemical mechanism is because if the AuAg NSs are exposed to a high concentration of halides and dissolved oxygen, Ag1 cations can be produced by galvanic corrosion without compromising the particles’ structural stability, and anodic stripping analysis can be performed. This proof-ofconcept approach allowed reaching high sensitivities down to 102 CFU mL21 in only 10 min. However, this assay was not able to distinguish and quantify different bacterial strains in complex mixtures and the presence of interfering species such as copper and mercury, lead to an electrochemical quenched effect due to suspected formation of alloys and amalgams between these cations (Cu21, Hg21) and the noble metals, Au and Ag, constituting the NSs, as reported in Fig. 13.9B. The use of AgNPs has been also adopted for the rapid detection of another human pathogen, the Staphylococcus aureus [52]. In this work, AgNPs were conjugated to an anti-S. aureus aptamer to be integrated into an immunoassay platform. Briefly, a biotinylated primary anti-S. aureus aptamer was fixed onto streptavidincoated magnetic beads that served as the capture agent. Subsequently, a second anti-S. aureus aptamer (conjugated to AgNPs by means of S Ag covalent bond) was allowed to form a sandwich structure with the bacterium, and the electrochemical signal of Ag ions was carried out by means of anodic stripping voltammetry (in strong acidic conditions). The electrochemical immunosensor displayed a dynamic range comprised between 10 and 106 CFU mL21 with a detection limit calculated

346

Handbook of Nanomaterials in Analytical Chemistry

(S/N 5 3) equal to 1 CFU mL21. Authors claimed that the sensitivity of the developed assay is strictly dependent on the Ag ions released by each NP, that is, 106 ions from a 40-nm particle. In addition, the use of AgNPs instead of AuNPs should be preferred also because the electrochemical redox reactions of Ag occur at lower potentials with respect to those needed by colloidal Au.

13.5.1.3 Cu nanoparticles and Pt nanoparticles Within the electrochemical development of sensors and biosensors, though the role of Au and Ag for making smart NPs represents the majority of applications, other metals can be obtained in form of NPs/nanocomposites such as copper and platinum. Even if their usage is not spread as well as the previous ones, some nice applications have been reported in literature. CuNPs have been used to modify the electrodic surface for the detection of nitrite and nitrate ions in food and beverages samples. The authors developed a sensing tool by electrodepositing CuNPs onto a layer composed by multiwalled CNTs-reduced GONs [45] (Fig. 13.9C). The presence of CuNPs was necessary to carry out nitrite and nitrate detection at the glassy carbon electrode. In addition, the combination between carbonaceous material and copper allowed reaching a two-fold enhancement of the platform sensitivity. Both the ions were detected by square-wave voltammetry within the 0.1 75 μM range with detection limits of 20 and 30 nM, respectively, for nitrate and nitrite ions. An experimental issue demonstrated the effect of chloride ions in solution, similar for the simultaneous determination of nitrite and nitrate: their presence might form a surface layer onto the modified electrode, altering the double layer characteristics; to avoid this, an Ag-impregnated filter could be used to remove the excess of chloride ions. The use of CuNPs has been also used to mimic the role of an enzyme. In fact, metal-organic frameworks (MOFs) have been used as an envelope for Cu NPs for nonenzymatic glucose sensing in alkaline media [53]. The encapsulated CuNPs in organic zeolitic imidazolate framework have been adsorbed onto a SPE. The presence of MOFs allowed to enhance the stability of CuNPs, preventing their dissolution and agglomeration during the electrocatalytic analysis. This effect was also confirmed through a comparison with a layer-by-layer approach, indicated by the authors as Cu-on, instead of Cu-in, that is, encapsulation. The use of transition metals such as copper was also convenient because of the easier controllable synthesis, higher activity and lower cost, if compared to Au-based platforms. The limit of detection was calculated to be 2.76 μM on the basis of S/N 5 3, and the linearity was observed up to 0.7 mM. In addition, this device was successfully compared with a commercial glucometer (One Touch Ultra, LifeScan), achieving a good agreement. Another example of electrocatalytic metal encapsulation is represented by platinum. With a similar strategy, platinum NPs (PtNPs) have been encapsulated into MOFs to detect the activity of telomerase [54]. It was detected in cancer cells following the electrocatalysis of PtNPs in the presence of NaBH4 oxidation in alkaline media. To perform the detection, a capture probe has been linked onto the

Nanomaterial-based sensors

347

PtNPs-MOF adduct, and it has been able to recognize DNA sequences related to telomerase extract. The electrochemical signal is produced following the addition of NaBH4 because its oxidation involves a maximum of eight electrons: this effect is much higher in respect to those involving one- or two-electron process. A traditional glassy carbon electrode was adopted to realize this biosensor, which showed a dynamic correlation with the telomerase activity from 500 to 107 cells mL21, and the activity calculated in a single cell was equal to 2 3 1011 IU.

13.5.1.4 Inorganic nanoparticles Not only metallic NPs have been used to enhance the electrochemical performance of sensors and biosensors. Plenty of nanomodifiers, including inorganic crystals, metal oxides, etc. have been used to develop the “right” platform. In the electrochemical field, one of these is without doubts the Prussian Blue also known as “artificial peroxidase” for its selectivity toward hydrogen peroxide [55]. The use of Prussian Blue (ferric hexacyanoferrate) has been widely adopted toward the determination of hydrogen peroxide, also in biosensing architectures involving the use of oxidase enzymes, that is, alcohol, glucose, lactate, cholesterol, etc. [56 58]. In particular, a novel approach has been recently used to produce Prussian Blue NPs: the cellulose network of filter paper has served as a reactor for fabricating these NPs [46]. Briefly, the structure of a common filter paper has been used to synthesize prussian blue nanoparticles (PBNPs) starting from their precursors without the need of any external power source and/or reducing agents. The synthesis has been entirely attributed to the composition and structure of paper, and NPs of B20 nm have been produced. This approach represented the first paper-based mediated synthesis of NPs and the so-called “Paper Blue” has been applied toward the detection of glucose in whole blood. This biosensor was capable to detect glucose linearly up to 25 mM, and the presence of Prussian Blue NPs highlighted a high selectivity even in the presence of common potential blood interferents, for example, ascorbic acid, uric acid, and acetaminophen. Moreover, this paper-based biosensor was positively compared with the commercially available strips (Bayer Contour) with a correlation of 0.987, as displayed in Fig. 13.9D. Beyond the activity toward hydrogen peroxide, PBNPs have been also used to detect thiols. In particular, combined with CB, for the development of organophosphate pesticide biosensor [59]. In this case, the synthesis of PBNPs was performed directly onto CB that acted as nucleating sites for NPs’ formation. After the nanocomposite was produced and purified, it was mechanically mixed within the carbon ink and screen-printed onto a waxed filter paper. The pesticide was detected by taking advantage of a dual electrochemical measurement, in parallel, of butyrylcholinesterase (BChE) enzyme activity toward butyrylthiocholine with and without pesticide (the enzyme inhibitor). This all-in-one biosensor allowed to detect the enzymatic inhibition caused by the presence of a model analyte, that is, paraoxon, linearly up to 25 μg L21 with a detection limit found equal to 3 μg L21. Another interesting biosensing approach has been reported by Rivas et al. while developing an aptasensor for ochratoxin A (OTA) [60]. This electrochemical

348

Handbook of Nanomaterials in Analytical Chemistry

platform has been obtained by electropolymerizing a film of polythionine onto a carbon SPE, followed by the assembly of iridium oxide NPs (IrO2NPs). The immobilization of the OTA-recognition aptamer was achieved through the electrostatic interactions produced as a consequence of the attraction between the negatively charged citrate groups surrounding IrO2NPs and the positively charged amino groups of the amino-modified aptamer. This platform allowed to develop a labelfree tool based on impedimetric detection of OTA in the interval between 0.01 and 100 nM with a detection limit of 14 pM.

13.5.2 Noncarbonaceous nanomaterials optical (bio)sensors 13.5.2.1 AuNPs A great possibility of using AuNPs in developing colorimetric assay, but even other metal-based nanomaterials, is attributable to the fact that the color of colloids depends on their shape and chemical environment. For instance, the use of 1-(2mercaptoethyl)-1,3,5-triazinane-2,4,6-trione (MTT)-functionalized AuNPs allowed detecting nitrite ions by exploiting the “molecular bridge” among the different MTT-AuNPs [61]. The presence of NO2 2 ion was capable to promote interactions between NPs, provoking the red wine color of MTT-AuNPs changing into the purple-gray color. The absorbance of the plasmonic band shifted from 535 to 790 nm, and it could be attributed to the closer contact among MTT-AuNPs, due to aggregation. The analytical performance was satisfactory: the linear regression of the calibration curve showed a good correlation coefficient (R2 5 0.9737), the detection limit was calculated equal to 1 μg mL21, and it was within the legal limits established by US EPA and WHO for drinking water. It should be noted that the presence of common interfering species such as fluoride, chloride, bromide, phosphate, sulfate, and nitrate ions, did not affect the nitrite analysis. Another elegant application of AuNPs has been reported toward the colorimetric detection of organophosphorous pesticides: the scheme of detection has been based on the enzymatic hydrolysis reaction of acetylcholinesterase (AChE) and the dissolution of AuNPs in Au31/cetyltrimethylammonium bromide (CTAB) [62], as reported in Fig. 13.10A. The dissolution of AuNPs represents a new mechanism: in fact, they can be dissolved by a mild oxidant in the presence of CTAB, exhibiting an evident shift from red to colorless. In this case, when the enzymatic substrate (acetylthiocoline) is converted by AChE, the by-product thiocholine protects AuNPs from dissolution; instead, when the inhibitor is present, the enzymatic reaction does not occur properly, AuNPs are oxidized to Au31/CTAB and the color changes from red to pink/colorless. Under the optimized conditions, parathion (the model inhibitor) was detected down to 0.7 ppb and the presence of small amount of salt (5 mM NaCl) did not affect the stability of method. Beyond these approaches, the use of AuNPs represents the “gold standard” in developing lateral flow immunoassays [66]. These NPs represent the starting point when this technology is required: the reason might be attributed to their color and the discrimination with respect to the colorless environment. Other reasons are

Nanomaterial-based sensors

349

Figure 13.10 (A) Schematic illustration of colorimetry for the assay of OPs based on the dissolution of AuNPs; (up) in the absence of organophosphorous pesticides (OPs), the enzymatic thiocholine (TCh) consumes the Au31 and prevents the dissolution of AuNPs, and (down) in the presence of OPs, the enzymatic TCh is not enough to consume all the Au31, and the residual Au31 dissolves the AuNPs [62]. (B) Cross-reaction of the three-colored probes used to label antibodies toward CAS (C-AuNP), HNP (M-AuNP), and OVA (YAgNP). The probes were mixed and applied to the YMC multiplex LFIA [63]. (C) Increase in absorbance with increasing concentration of picric acid [64]. (D) Schematic representation of BChE activity visualization, including the enzymatic reaction and the prussian blue (PB) fading [65].

linked to the easiness in conjugation with antibody and/or other species necessary for the lateral flow immunotests, and the low cost. Recently, AuNPs have been integrated into a paper-based immunoassay strip for the detection of uranium in groundwater [67]. The mechanism of the detection is founded on the fact that a monoclonal antibody (clone 12F6) is capable to specifically recognizes U(VI) when complexed to a chelator, the 2,9-dicarboxyl-1,10-phenanthroline (DCP). To reveal U(VI) complex, AuNPs have been conjugated to the antibody and due to the small size of the U-DCP complex, a competitive assay was realized. With this approach, a limit of detection of B37 nM has been obtained and it should be noted that this result well meets the legal limit of 126 nM set by the WHO and the US EPA for drinking water.

13.5.2.2 AgNPs As well as for the electrochemical-based detection, the amount of procedures that employ the use of AgNPs to realize colorimetric tests are lower in respect to those based on the use of Au colloids. The main reason is attributable to the starting color

350

Handbook of Nanomaterials in Analytical Chemistry

of AgNPs: in fact, differently from the red-based color of AuNPs, the color of AgNPs is usually yellowish. Moreover, the use of AgNPs is reported in literature particularly due to the simplicity in synthesis and to the low cost of the precursors. Recently, Peng et al. developed a method for the detection of ascorbic acid by taking into consideration the growth of AgNPs following a green photo-catalytic route [68]. Briefly, Ag nanoclusters (AgNCs) are obtained by two steps: UV-mediated photosynthesis of NCs with papain and catalytic growth of AgNPs in the presence of ascorbic acid. The difference between the NCs and NPs is in the color; while the former is colorless, the latter is yellow. The NCs represent the catalyst for promoting the synthesis of AgNPs, with an associated change of the plasmon absorption spectra at 420 nm. With this procedure, ascorbic acid has been detected in the range comprised between 0.25 and 50 μM, with a limit of detection as low as B79 nM (using a spectrophotometer), while the detection limit observed for colorimetric assays taken by the photographs was B1 μM. Another approach reported in literature has been consistent with the aggregation of AgNPs for the detection of DNA related to Middle East respiratory syndrome coronavirus (MERS-CoV), Mycobacterium tuberculosis (MTB), and human papillomavirus (HPV) [69]. A paper-based multiassay has been developed for using as the detection principle the aggregation of NPs. The AgNPs are stabilized by the citrate ions that give the traditional yellow color. If the cationic PNA probe is not bound to its target, the PNA can interact with the negatively charged AgNPs leading to NP aggregation and a significant color change (from yellow to colorless); instead, a DNA PNA duplex can be formed when target is present in solution, leading to an electrostatic repulsion of the AgNPs that do not aggregate. Under the optimized condition, the limit of detection for MERS-CoV, MTB, and HPV were found to be 1.53, 1.27, and 1.03 nM, respectively. However, the yellow color of AgNPs might represents an added value when a multi-chromatic lateral flow assay needs to be developed. The group of Anfossi took advantage of spherical AgNPs, characterized by a brilliant yellow color, to realize a trichromatic lateral flow immunoassay that was capable to detect allergenic proteins, namely casein, ovalbumin, and hazelnut allergenic protein, at levels as low as 0.1 mg L21 [63]. AgNPs were conjugated with anti-ovalbumin antibody, while two different sized (and then differently colored, i.e., red and cyan) AuNPs were conjugated with the anticasein and antihazelnut allergenic protein antibodies. This strategy allowed an obvious identification of the three allergens in commercial biscuits based on the color of the probes; the following three combinations cyan/ casein, yellow/ovalbumin, and magenta/hazelnut protein, have been used for visual discrimination (Fig. 13.10B).

13.5.2.3 CuNPs and PtNPs Differently from AuNPs and AgNPs, the making of CuNPs is more challenging because of their easy oxidation, especially when exposed to air or aqueous solution. However, two features make copper suitable in colorimetric analytical tools

Nanomaterial-based sensors

351

development: copper is less expensive than Au and Ag, and the surface plasmon resonance band is similar to AuNPs and AgNPs. In 2016, CuNPs have been produced by using the fatty acid amide N-lauryltyramine and hydrazine as capping and reducing agent, respectively [70]. Compared to the other metal-based NPs, the surface plasmon resonance band is centered B580 nm, and the color of the dispersion appears intense brown. It has been demonstrated how in presence of cysteine (Cys), a color change from brown to olive green is observed. They observed that the color change happened only when both the thiol (SH) and amine (NH2) groups were present in the analyte: CuNPs detected Cys after 2 min while 3 h were necessary to sense L-cysteine ethyl ester (CEE). This behavior can be attributed to the bulkier size of CEE, which may have delayed the contact of SH and NH2 group with CuNPs. The absorbance peak of CuNPs decreased when the Cys concentration increased, displaying a linear range up to 25 μM with a detection limit of 0.1 μM. Another interesting application of CuNPs has been demonstrated toward the detection of picric acid in real water samples [64]. 30-nm CuNPs have been synthesized by using cefuroxime drug as a protecting agent: the amide group of cefuroxime takes part in coordination with CuNPs, preventing aggregation and acting as capping agent, with the formation of spherical and stable NPs. Authors observed a change in color from red to yellow, supposed to be a consequence of complexation between picric acid and capped-CuNPs: picric acid removes cefuroxime around CuNPs, provoking the aggregation of NPs. The limit of detection was determined to be 38 nM, and the method was capable to provide a linear signal up to a level of 20 μM of picric acid. In addition, the system was evaluated also in presence of species commonly present in aqueous matrices such as pentachlorophenol, 4-nitroanaline, hydroquinone, Cd21, Ni21, Co21, As31, Cr31 and Hg21, but only the presence of picric acid was consistent with color change from red to yellow as shown in Fig. 13.10C. Among the noble metals, platinum is often used in developing colorimetric assays even if its use in form of NPs is often related to its enzyme-like activity. Chau et al. demonstrated the effectiveness of PtNPs on reduced GO as peroxidase mimetic for the colorimetric detection of specific DNA sequences [71]. In particular, authors took advantage of the synergic combination of PtNPs and graphene: the former is characterized by a peroxidase-like activity, the latter allows stacking interactions with ss-DNA but not with the ds ones. The assay involved the hybridization of a target sequence with its complementary probe sequence, followed by the addition of hybrid nanocomposite PtNPs/rGO. If the concentration of target is low, the nanocomposite is able to bind with the single-stranded probe and it is stabilized against aggregation. After centrifugation, the addition of tetramethylbenzidine (TMB) and hydrogen peroxide leads to an intense blue color. Instead, if the level of target is high, the target/probe duplex can be formed, making the nanocomposite aggregated and thus reducing the recovered PtNPs/rGO after centrifugation; the result is a pale blue production upon the addition of TMB and hydrogen peroxide. The linear range and limit of detection of this assay platform were 0.5 10 and 0.4 nM, respectively.

352

Handbook of Nanomaterials in Analytical Chemistry

13.5.2.4 Inorganic nanoparticles The effectiveness of Prussian Blue is not only visible from an electrochemical point of view, in fact, the role of Prussian Blue in electrocatalyzing the reduction of hydrogen peroxide and the oxidation of thiols is due to a redox couple: Prussian Blue and Prussian White, respectively, the oxidized and the reduced forms. Beyond the electrochemical properties, this material is very interesting because of its change in color between the different oxidation states: when Prussian Blue is reduced to Prussian White, its color changes from blue to colorless. Having in mind this mechanism, Bagheri and colleagues developed the first paper-based multiplatform highlighting the fading of Prussian Blue for sensing the enzymatic activity [65], as reported in Fig. 13.10D. They reported a 96-well chromatographic paper-based platform for the detection of BChE enzyme activity in human serum. Prussian Blue NPs were reagentlessly synthesized within the paper’s structure as already reported [65]. The principle of BChE activity detection relies on the reaction between the enzymatic product thiocholine and Prussian Blue. The presence of thiocholine is able to reduce Prussian Blue forming the reduced form, namely Prussian White. The use of a common office scanner was sufficient to detect BChE activity down to 0.8 U mL21 and linearly within a range of 2 15 U mL21. Another innovative nanomaterial for optical biosensing is Nanoceria, which is a rare-earth oxide nanostructure material, with unique physical and chemical properties compared with that of its bulk material. The Ce31/Ce41 ratio present in Nanoceria significantly affects its peroxidase-mimetic activity. The combination of this novel material with porphyrin has been evaluated in order to estimate the advantage in adopting a functional molecular material with large conjugated electronic structure. Liu et al. prepared a nanocomposite made with ceria nanorods and 5,10,15,20-tetrakis(4-carboxyl phenyl)-porphyrin (H2TCPP), namely H2TCPP CeO2 [72]. This nanocomposite exhibited an intrinsic peroxidase-like activity toward hydrogen peroxide and TMB similarly to horseradish peroxidase enzyme. The combination of these two materials led to a synergistic effect: the electrons can be easily transferred from the conduction band of porphyrin to the conduction band ceria due to the lower level of CeO2 than that of porphyrin. In the presence of glucose oxidase, the reported approach was capable to detect glucose down to 3.3 3 1025 M within a dynamic range between 5.0 3 1025 and 1.0 3 1024 M. However, as for the previous section, the use of this nanocomposite in majority is related to its enzyme-like activity. Differently from metal NPs, most of the inorganic nanomaterials have been used by taking into advantage their properties of artificial enzymes and they are often combined with coreactant that can change color after some reaction as well as TMB.

13.6

Nano/micromotors

Recent trend also includes moving from “classic” substrates to “active” substrate, by the use of self-propelled micro/nanomachines for sensing, which consist of

Nanomaterial-based sensors

353

Figure 13.11 (A) Mechanism and reactions involved in the OP nerve agents degradation to p-nitrophenol accelerated by microengines [76]. (B) Schematic of the colorimetric assay with SW 2 Fe2O3/MnO2 micromotors for phenylenediamines detection [77].

moving the receptor around the sample, the dimension of those machines ranges from nano to micrometers, and can be fabricated using a wide variety of polymers, metals, and semiconductors [73 75]. In terms of application, they are still at a proof-of-concept stage of tiny objects demonstrating capabilities to autonomously perform different tasks: transporting cargo, destroying cells, remediate pollution. In this direction, the integration of nano/micro entities within electroanalytical and colorimetric devices is highly recommendable. The first combination of micromotors with a SPE has been reported, using Mg-Au-Ni Janus microengines for accelerated destruction of nerve agents, and consequent detection of the non-hazardous remediated product (p-nitrophenol) [76]. In this work, smart micromotors were capable of producing OH2 ions to increase the pH of the medium and consequently promote the alkaline degradation of paraoxon into a readily detectable p-nitrophenol, Fig. 13.11A. In addition, the produced H2 allowed obtaining a rapid and reproducible nerve-agent degradation with a subsequent detection without the need of external stirrers or mixing devices. The use of microengines leads to a 15-fold increased sensitivity toward organophosphate pesticide detection, compared to a nonengineered SPE. This combined platform represented the first example of an alternative built-in mixing in electroanalysis. The same principle was successively taken as inspiration by the group of Escarpa, which used an Au-Mg micromotor-based platform for electrochemical detection of diphenyl phthalate in biological and food samples [78]. Also in this case, the increase of pH due to the presence of micromotors, allowed converting diphenyl phthalate into phenol (electroactive molecule). The methodology was applied for direct analysis of phthalate in human plasma, milk, and whiskey, without any sample treatment. The same group developed a colorimetric method based on the use of tubular micromotors composed of a hybrid SWCNT-Fe2O3 outer layer and powered by a MnO2 catalyst for the detection and discrimination of phenylenediamine isomers [77] (Fig. 13.11B). In just 15 min, the catalytic decomposition of hydrogen peroxide

354

Handbook of Nanomaterials in Analytical Chemistry

(the fuel) caused by the MnO2 catalytic layer resulted in the production of O2 bubbles along with hydroxyl radicals for analytes dimerization. Experimentally, authors observed that o-phenylenediamine and p-phenylenediamine solutions (500 μM) exhibited strong yellow and pink color, respectively, after 30 min of micromotor’s action in presence of 5% H2O2. A blue solution was obtained when an equimolar mixture of the two isomers was used. The micromotor movement along with radical generation resulted in low limits of detection (5 and 6 μM) and quantification (17 and 20 μM), respectively for o-phenylenediamine and p-phenylenediamine.

13.7

Conclusions

In this chapter, some interesting applications of nanomaterials for the development of analytical devices are presented. The use of nanosized materials belonging from carbonaceous, metallic, or inorganic sources confers to the realized devices improved characteristics of cost-effectiveness, high sensitivity and selectivity, lowest limit of detection, and long-term stability. As illustrated, these NPs are suitable to be combined with each other and/or with different biological elements, producing new nanocomposites always with enhanced performances. Their use also permits for the miniaturization of the platforms, allowing for the realization of wearable devices for the real-time monitoring of physiological parameters. In addition, the miniaturization of platforms paves the way for coupling them with another emerging field: the wearable electronics. The wearable technology market actually shows a very fast growth, being currently worth $30 billion and predicted to rise to $150 billion by 2026, including an expected compound annual growth rate of 32% for wearable chemical sensors for the next 10 years, as stated by the report “Wearable Technology 2016-2026: IDTechEx”, June 30, 2016 [79]. In our opinion, this field represents one of the future aspects of the research in sensing devices, which requires a strict synergy between different expertizes such as those of chemical, engineering, materials, and biological areas, boosting the multifarious vision of science.

Acknowledgments F.A. and V.S. acknowledge NanoSWS project EraNetMed—RQ3-2016 and AlgaeCB Bilateral Project Italy-Morocco 2018/2019. F.A. also acknowledges Nanospes Project, University of Rome “Tor Vergata” and Innoconcrete Project “Con il contributo del Ministero dell’Istruzione dell’Universita` e della Ricerca della Repubblica Italiana”. V.S. also acknowledges AdSWiM Interreg Project Italy-Croatia 2019/2020. S.C. acknowledges Marie Skłodowska-Curie Actions Individual Fellowship, this project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 794007.

Nanomaterial-based sensors

355

References [1] F. Arduini, S. Cinti, V. Scognamiglio, D. Moscone, G. Palleschi, How cutting-edge technologies impact the design of electrochemical (bio) sensors for environmental analysis. A review, Anal. Chim. Acta 959 (2017) 15 42. [2] http://graphene-flagship.eu/. [3] Y. Ito, F. Fukusaki, DNA as a ‘nanomaterial’, J. Mol. Catal B-Enzym. 28 (2004) 155 166. [4] A.V. Pinheiro, D. Han, W.N. Shih, H. Yan, Challenges and opportunities for structural DNA nanotechnology, Nat. Nanotechnol. 6 (2011) 763. [5] J.A. Gerrard, Protein nanotechnology: what is it? Protein Nanotechnology, Humana Press, Totowa, NJ, 2013, pp. 1 15. [6] https://www.nature.com/collections/vvtzhkzbhm. [7] F. Arduini, S. Cinti, V. Scognamiglio, D. Moscone, Nanomaterials in electrochemical biosensors for pesticide detection: advances and challenges in food analysis, Microchim. Acta 183 (2016) 2063 2083. [8] M. Arvand, N. Ghodsi, M.A. Zanjanchi, A new microplatform based on titanium dioxide nanofibers/graphene oxide nanosheets nanocomposite modified screen printed carbon electrode for electrochemical determination of adenine in the presence of guanine, Biosens. Bioelectron. 77 (2016) 837 844. [9] J. Ping, Y. Wang, Y. Ying, J. Wu, Application of electrochemically reduced graphene oxide on screen-printed ion-selective electrode, Anal. Chem. 84 (2012) 3473 3479. [10] L. Li, L. Zhang, J. Yu, S. Ge, X. Song, All-graphene composite materials for signal amplification toward ultrasensitive electrochemical immunosensing of tumor marker, Biosens. Bioelectron. 71 (2015) 108 114. [11] J. Ping, Y. Wang, K. Fan, J. Wu, Y. Ying, Direct electrochemical reduction of graphene oxide on ionic liquid doped screen-printed electrode and its electrochemical biosensing application, Biosens. Bioelectron. 28 (2011) 204 209. [12] A. Bonanni, C.K. Chua, G. Zhao, Z. Sofer, M. Pumera, Inherently electroactive graphene oxide nanoplatelets as labels for single nucleotide polymorphism detection, ACS Nano 6 (2012) 8546 8551. [13] E. Morales-Narva´ez, L. Baptista-Pires, A. Zamora-Ga´lvez, A. Merkoc¸i, Graphene-based biosensors: going simple, Adv. Mater. 29 (2017) 1604905. [14] J. Pen˜a-Bahamonde, H.N. Nguyen, S.K. Fanourakis, D.F. Rodrigues, Recent advances in graphene-based biosensor technology with applications in life sciences, J. Nanobiotechnol. 16 (2018) 75. [15] S.R. Ryoo, J. Lee, J. Yeo, H.K. Na, Y.K. Kim, H. Jang, et al., Quantitative and multiplexed microRNA sensing in living cells based on peptide nucleic acid and nano graphene oxide (PANGO), ACS Nano 7 (2013) 5882 5891. [16] E. Morales-Narva´ez, A.R. Hassan, A. Merkoc¸i, Graphene oxide as a pathogen-revealing agent: sensing with a digital-like response, Angew. Chem. 125 (2013) 14024 14028. [17] S. Iijima, Helical microtubules of graphitic carbon, Nature 354 (1991) 56 58. [18] S. Scognamiglio, Nanotechnology in glucose monitoring: advances and challenges in the last 10 years, Biosens. Bioelectron. 47 (2013) 12 25. [19] J. Dong, X. Wang, F. Qiao, P. Liu, S. Ai, Highly sensitive electrochemical stripping analysis of methyl parathion at MWCNTs CeO2 Au nanocomposite modified electrode, Sensor. Actuator. B 186 (2013) 774 780.

356

Handbook of Nanomaterials in Analytical Chemistry

[20] H. Huang, T. Chen, X. Liu, H. Ma, Ultrasensitive and simultaneous detection of heavy metal ions based on three-dimensional graphene-CNTs hybrid electrode materials, Anal. Chim. Acta 852 (2014) 45 54. [21] F.C. Vicentini, B.C. Janegitz, C.M. Brett, O. Fatibello-Filho, Tyrosinase biosensor based on a glassy carbon electrode modified with multi-walled carbon nanotubes and 1-butyl-3-methylimidazolium chloride within a dihexadecylphosphate film, Sens. Actuators B 188 (2013) 1101 1108. [22] M. Sireesha, V. Jagadeesh Babu, A.S. Kranthi Kiran, S. Ramakrishna, A review on carbon nanotubes in biosensor devices and their applications in medicine, Nanocomposites 4 (2018) 36 57. [23] S. Kruss, A.J. Hilmer, J. Zhang, N.F. Reuel, B. Mu, M.S. Strano, Carbon nanotubes as optical biomedical sensors, Adv. Drug Deliver. Rev. 65 (2013) 1933 1950. [24] V. Tjong, H. Yu, A. Hucknall, S. Rangarajan, A. Chilkoti, Amplified on-chip fluorescence detection of DNA hybridization by surface-initiated enzymatic polymerization, Anal. Chem. 83 (2011) 5153 5159. [25] J.J. Crochet, J.G. Duque, J.H. Werner, S.K. Doorn, Photoluminescence imaging of electronic-impurity-induced exciton quenching in single-walled carbon nanotubes, Nat. Nanotechnol. 7 (2012) 126. [26] H. Jin, D.A. Heller, M. Kalbacova, J.H. Kim, J. Zhang, A.A. Boghossian, et al., Detection of single-molecule H2O2 signalling from epidermal growth factor receptor using fluorescent single-walled carbon nanotubes, Nat. Nanotechnol. 5 (2010) 302. [27] J.H. Kim, D.A. Heller, H. Jin, P.W. Barone, C. Song, J. Zhang, et al., The rational design of nitric oxide selectivity in single-walled carbon nanotube near-infrared fluorescence sensors for biological detection, Nat. Chem. 1 (2009) 473. [28] Z. Chen, S.M. Tabakman, A.P. Goodwin, M.G. Kattah, D. Daranciang, X. Wang, et al., Protein microarrays with carbon nanotubes as multicolor Raman labels, Nat. Biotechnol. 26 (2008) 1285. [29] J.H. Kim, J.H. Ahn, P.W. Barone, H. Jin, J. Zhang, D.A. Heller, et al., A luciferase/ single-walled carbon nanotube conjugate for near-infrared fluorescent detection of cellular ATP, Angew. Chem. 122 (2010) 1498 1501. [30] H. Yoon, J.H. Ahn, P.W. Barone, K. Yum, R. Sharma, A.A. Boghossian, et al., Periplasmic binding proteins as optical modulators of single-walled carbon nanotube fluorescence: amplifying a nanoscale actuator, Angew. Chem. 123 (2011) 1868 1871. [31] J.H. Ahn, J.H. Kim, N.F. Reuel, P.W. Barone, A.A. Boghossian, J. Zhang, et al., Labelfree, single protein detection on a near-infrared fluorescent single-walled carbon nanotube/protein microarray fabricated by cell-free synthesis, Nano Lett. 11 (2011) 2743 2752. [32] F. Arduini, A. Amine, C. Majorani, F. Di Giorgio, D. De Felicis, F. Cataldo, et al., High performance electrochemical sensor based on modified screen-printed electrodes with cost-effective dispersion of nanostructured carbon black, Electrochem. Commun. 12 (2010) 346 350. [33] F. Arduini, F. Giorgio, A. Amine, F. Cataldo, D. Moscone, G. Palleschi, et al., Electroanalytical characterization of carbon black nanomaterial paste electrode: development of highly sensitive tyrosinase biosensor for catechol detection, Anal. Lett. 43 (2010) 1688 1702. [34] E.V. Suprun, F. Arduini, D. Moscone, G. Palleschi, V.V. Shumyantseva, A.I. Archakov, Direct electrochemistry of heme proteins on electrodes modified with didodecyldimethyl ammonium bromide and carbon black, Electroanalysis 24 (2012) 1923 1931.

Nanomaterial-based sensors

357

[35] D. Talarico, F. Arduini, A. Constantino, M. Del Carlo, D. Compagnone, D. Moscone, et al., Carbon black as successful screen-printed electrode modifier for phenolic compound detection, Electrochem. Commun. 60 (2015) 78 82. [36] T.W. Lo, L. Aldous, R.G. Compton, The use of nano-carbon as an alternative to multiwalled carbon nanotubes in modified electrodes for adsorptive stripping voltammetry, Sens. Actuat. B 162 (2012) 361 368. [37] C.H.A. Wong, A. Ambrosi, M. Pumera, Thermally reduced graphenes exhibiting a close relationship to amorphous carbon, Nanoscale 4 (2012) 4972 4977. [38] F.C. Vicentini, P.A. Raymundo-Pereira, B.C. Janegitz, S.A. Machado, O. FatibelloFilho, Nanostructured carbon black for simultaneous sensing in biological fluids, Sens. Actuat. B 227 (2016) 610 618. [39] R.V. Shamagsumova, D.N. Shurpik, P.L. Padnya, I.I. Stoikov, G.A. Evtugyn, Acetylcholinesterase biosensor for inhibitor measurements based on glassy carbon electrode modified with carbon black and pillar[5]arene, Talanta 144 (2015) 559 568. [40] S. Cinti, F. Limosani, M. Scarselli, F. Arduini, Magnetic carbon spheres and their derivatives combined with printed electrochemical sensors, Electrochim. Acta 282 (2018) 247 254. [41] E. Morales-Narva´ez, B. Pe´rez-Lo´pez, L.B. Pires, A. Merkoc¸i, Simple Fo¨rster resonance energy transfer evidence for the ultrahigh quantum dot quenching efficiency by graphene oxide compared to other carbon structures, Carbon 50 (2012) 2987 2993. [42] Y. Wang, L. Bao, Z. Liu, D.W. Pang, Aptamer biosensor based on fluorescence resonance energy transfer from upconverting phosphors to carbon nanoparticles for thrombin detection in human plasma, Anal. Chem. 83 (2011) 8130 8137. [43] E. Priyadarshini, N. Pradhan, Gold nanoparticles as efficient sensors in colorimetric detection of toxic metal ions: a review, Sens. Actuat. B 238 (2017) 888 902. [44] S. Cinti, E. Proietti, F. Casotto, D. Moscone, F. Arduini, Paper-based strips for the electrochemical detection of single and double stranded DNA, Anal. Chem. 90 (2018) 13680 13686. [45] H. Bagheri, A. Hajian, M. Rezaei, A. Shirzadmehr, Composite of Cu metal nanoparticles-multiwall carbon nanotubes-reduced graphene oxide as a novel and high performance platform of the electrochemical sensor for simultaneous determination of nitrite and nitrate, J. Hazard. Mat. 324 (2017) 762 772. [46] S. Cinti, R. Cusenza, D. Moscone, F. Arduini, Paper-based synthesis of Prussian Blue nanoparticles for the development of whole blood glucose electrochemical biosensor, Talanta 187 (2018) 59 64. [47] S. Cinti, S. Politi, D. Moscone, G. Palleschi, F. Arduini, Stripping analysis of As (III) by means of screen-printed electrodes modified with gold nanoparticles and carbon black nanocomposite, Electroanalysis 26 (2014) 931 939. [48] S. Cinti, F. Santella, D. Moscone, F. Arduini, Hg2 1 detection using a disposable and miniaturized screen-printed electrode modified with nanocomposite carbon black and gold nanoparticles, Environ. Sci. Pollut. Res. 23 (2016) 8192 8199. [49] A. de la Escosura-Mun˜iz, L. Baptista-Pires, L. Serrano, L. Altet, O. Francino, A. Sa´nchez, et al., Magnetic bead/gold nanoparticle double-labeled primers for electrochemical detection of isothermal amplified leishmania DNA, Small 12 (2016) 205 213. [50] J. Huang, Z. Xie, Z. Xie, S. Luo, L. Xie, L. Huang, et al., Silver nanoparticles coated graphene electrochemical sensor for the ultrasensitive analysis of avian influenza virus H7, Anal. Chim. Acta 913 (2016) 121 127.

358

Handbook of Nanomaterials in Analytical Chemistry

[51] L. Russo, J. Leva Bueno, J.F. Bergua, M. Costantini, M. Giannetto, V. Puntes, et al., Low-cost strategy for the development of a rapid electrochemical assay for bacteria detection based on AuAg nanoshells, ACS Omega 3 (2018) 18849 18856. [52] A. Abbaspour, F. Norouz-Sarvestani, A. Noori, N. Soltani, Aptamer-conjugated silver nanoparticles for electrochemical dual-aptamer-based sandwich detection of Staphylococcus aureus, Biosens. Bioelectron. 68 (2015) 149 155. [53] L. Shi, X. Zhu, T. Liu, H. Zhao, M. Lan, Encapsulating Cu nanoparticles into metalorganic frameworks for nonenzymatic glucose sensing, Sens. Actuat. B 227 (2016) 583 590. [54] P. Ling, J. Lei, L. Jia, H. Ju, Platinum nanoparticles encapsulated metal organic frameworks for the electrochemical detection of telomerase activity, Chem. Commun. 52 (2016) 1226 1229. [55] A.A. Karyakin, E.E. Karyakina, L. Gorton, Amperometric biosensor for glutamate using prussian blue-based “artificial peroxidase” as a transducer for hydrogen peroxide, Anal. Chem. 72 (2000) 1720 1723. [56] S. Cinti, F. Arduini, G. Vellucci, I. Cacciotti, F. Nanni, D. Moscone, Carbon black assisted tailoring of Prussian Blue nanoparticles to tune sensitivity and detection limit towards H2O2 by using screen-printed electrode, Electrochem. Commun. 47 (2014) 63 66. [57] S. Cinti, M. Basso, D. Moscone, F. Arduini, A paper-based nanomodified electrochemical biosensor for ethanol detection in beers, Anal. Chim. Acta. 960 (2017) 123 130. [58] S. Cinti, F. Arduini, D. Moscone, G. Palleschi, L. Gonzalez-Macia, A.J. Killard, Cholesterol biosensor based on inkjet-printed Prussian blue nanoparticle-modified screen-printed electrodes, Sens. Actuat. B 221 (2015) 187 190. [59] S. Cinti, C. Minotti, D. Moscone, G. Palleschi, F. Arduini, Fully integrated ready-touse paper-based electrochemical biosensor to detect nerve agents, Biosens. Bioelectron. 93 (2017) 46 51. [60] L. Rivas, C.C. Mayorga-Martinez, D. Quesada-Gonza´lez, A. Zamora-Ga´lvez, A. de la Escosura-Mun˜iz, A. Merkoc¸i, Label-free impedimetric aptasensor for ochratoxin-A detection using iridium oxide nanoparticles, Anal. Chem. 87 (2015) 5167 5172. [61] Y.S. Nam, K.C. Noh, N.K. Kim, Y. Lee, H.K. Park, K.B. Lee, Sensitive and selective determination of NO22 ion in aqueous samples using modified gold nanoparticle as a colorimetric probe, Talanta 125 (2014) 153 158. [62] S. Wu, D. Li, J. Wang, Y. Zhao, S. Dong, X. Wang, Gold nanoparticles dissolution based colorimetric method for highly sensitive detection of organophosphate pesticides, Sens. Actuat. B 238 (2017) 427 433. [63] L. Anfossi, F. Di Nardo, A. Russo, S. Cavalera, C. Giovannoli, G. Spano, et al., Silver and gold nanoparticles as multi-chromatic lateral flow assay probes for the detection of food allergens, Anal. Bioanal. Chem. (2018). Available from: https://doi.org/10.1007/ s00216-018-1451-6. [64] M. Hussain, A. Nafady, S.T.H. Sherazi, M.R. Shah, A. Alsalme, M.S. Kalhoro, et al., Cefuroxime derived copper nanoparticles and their application as a colorimetric sensor for trace level detection of picric acid, RSC Adv. 6 (2016) 82882 82889. [65] N. Bagheri, S. Cinti, V. Caratelli, R. Massoud, M. Saraji, D. Moscone, et al., A 96-well wax printed Prussian Blue paper for the visual determination of cholinesterase activity in human serum, Biosens. Bioelectron. (2019). Available from: https://doi.org/10.1016/ j.bios.2019.03.037. [66] D. Quesada-Gonzalez, A. Merkoci, Nanoparticle-based lateral flow biosensors, Biosens. Bioelectron. 73 (2015) 47 63.

Nanomaterial-based sensors

359

[67] D. Quesada-Gonza´lez, G.A. Jairo, R.C. Blake, D.A. Blake, A. Merkoc¸i, Uranium (VI) detection in groundwater using a gold nanoparticle/paper-based lateral flow device, Sci. Rep. 8 (2018) 16157. [68] J. Peng, J. Ling, X.Q. Zhang, L.Y. Zhang, Q.E. Cao, Z.T. Ding, A rapid, sensitive and selective colorimetric method for detection of ascorbic acid, Sens. Actuat. B 221 (2015) 708 716. [69] P. Teengam, W. Siangproh, A. Tuantranont, T. Vilaivan, O. Chailapakul, C.S. Henry, Multiplex paper-based colorimetric DNA sensor using pyrrolidinyl peptide nucleic acid-induced AgNPs aggregation for detecting MERS-CoV, MTB, and HPV oligonucleotides, Anal. Chem. 89 (2017) 5428 5435. [70] K.B.A. Ahmed, M. Sengan, S. Kumar, A. Veerappan, Highly selective colorimetric cysteine sensor based on the formation of cysteine layer on copper nanoparticles, Sens. Actuat. B 233 (2016) 431 437. [71] L.Y. Chau, Q. He, A. Qin, S.P. Yip, T.M. Lee, Platinum nanoparticles on reduced graphene oxide as peroxidase mimetics for the colorimetric detection of specific DNA sequence, J. Mater. Chem. B 4 (2016) 4076 4083. [72] Q. Liu, Y. Ding, Y. Yang, L. Zhang, L. Sun, P. Chen, et al., Enhanced peroxidase-like activity of porphyrin functionalized ceria nanorods for sensitive and selective colorimetric detection of glucose, Mater. Sci. Eng. C 59 (2016) 445 453. [73] J. Wang, W. Gao, Nano/microscale motors: biomedical opportunities and challenges, ACS Nano 6 (2012) 5745 5751. [74] J. Wang, Cargo-towing synthetic nanomachines: towards active transport in microchip devices, Lab Chip 12 (2012) 1944 1950. [75] W. Wang, W. Duan, S. Ahmed, T.E. Mallouk, A. Sen, Small power: autonomous nanoand micromotors propelled by self-generated gradients, Nano Today 8 (2013) 531 554. [76] S. Cinti, G. Valde´s-Ramı´rez, W. Gao, J. Li, G. Palleschi, J. Wang, Microengineassisted electrochemical measurements at printable sensor strips, Chem. Commun. 51 (2015) 8668 8671. [77] R. Marı´a-Hormigos, B. Jurado-Sa´nchez, A. Escarpa, Self-propelled micromotors for naked-eye detection of phenylenediamines isomers, Anal. Chem. 90 (2018) 9830 9837. [78] D. Rojas, B. Jurado-Sa´nchez, A. Escarpa, “Shoot and sense” Janus micromotors-based strategy for the simultaneous degradation and detection of persistent organic pollutants in food and biological samples, Anal. Chem. 88 (2016) 4153 4160. [79] http://www.idtechex.com/research/reports/wearable-technology-2016-2026-000483.asp.

MXene-based sensors and biosensors: next-generation detection platforms

14

Ankita Sinha1, Dhanjai2,3,4, Samuel M. Mugo3, Jiping Chen4 and Koodlur S. Lokesh5 1 Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian, P.R. China, 2Department of Mathematical and Physical Sciences, Concordia University of Edmonton, Edmonton, AB, Canada, 3Department of Physical Sciences, MacEwan University, Edmonton, AB, Canada, 4CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian P.R. China, 5Department of Chemistry/Industrial Chemistry, Vijayanagara Sri Krishnadevaraya University, Ballari, India

14.1

Introduction

In current times, two-dimensional (2D) layered materials have withdrawn considerable attention due to their morphological resemblance with graphene. So far, 2D materials such as transition metal dichalcogenides and boron nitride have been extensively studied for their significant applications in the fields of electronics, catalysis, energy etc. [1
4]. Recently, MXene has emerged as a unique 2D material that mainly includes early transition metal carbides, nitrides, and carbonitrides [5
9]. MXene possesses layered morphology and are produced by etching layers of sp elements from three-dimensional (3D) MAX phases [9]. MAX phases are layered hexagonal with P63/mmc symmetry with general formula Mn11AXn (n 5 1, 2, 3) where M represents d-block transition metals, A represents main group 13 and 14 elements, and X is either C or N atoms [5
7]. The M
X bond holds covalent/metallic/ionic character, whereas M
A bond is of pure metallic nature [5]. Therefore, at high temperatures, M
A bond decomposes into Mn11Xn, which results into recrystallization and formation of 3D Mn11Xn rocksalt-like structure [6]. Selective etching of reactive A layers from their MAX phases can be done using suitable chemicals without destroying MX layers (Fig. 14.1A) [6,8]. The process leads to the formation of highly stable closely packed Mn11XnTx layers, where Tx is the surface-terminating functional group such as oxygen (O), fluorine (
F), or hydroxyl (
OH) (Fig. 14.1B) [5,6,10]. For example, preparation of 2D Ti3C2 can be performed by exfoliation

Handbook of Nanomaterials in Analytical Chemistry. DOI: https://doi.org/10.1016/B978-0-12-816699-4.00014-1 Copyright © 2020 Elsevier Inc. All rights reserved.

362

Handbook of Nanomaterials in Analytical Chemistry

Figure 14.1 (A) Exfoliation of MAX phases and preparation of 2D MXene sheets, (B) Ti3C2Tx structure showing terminating groups on the surface of Ti3C2Tx nanosheets, (C) SEM, (D) TEM, (E) HRTEM, (F) SAED, (G) XRD, (H) FTIR of Ti3C2 MXene [6,10]. Source: Reprinted with permission from M. Naguib, O. Mashtalir, J. Carle, V. Presser, J. Lu, L. Hultman, et al., Two dimensional transition metal carbides, ACS Nano 6 (2012) 1322
1331; E. Lee, A.V. Mohammadi, B.C. Prorok, Y.S. Yoon, M. Beidaghi, D.J. Kim, Room temperature gas sensing of two-dimensional titanium carbide (MXene), ACS Appl. Mater. Interfaces, 9 (2017) 37184
37190.

of Ti3AlC2 in 50% hydrogen fluride (HF) at room temperature for 2 h as per the following reactions [5,6]; Mn11 AlXn 1 3HF 5 AlF3 1 Mn11 Xn 1 1:5 H2

(14.1)

Mn11 Xn 1 2H2 O 5 Mn11 Xn ðOHÞ2 1 H2

(14.2)

Mn11 Xn 1 2HF 5 Mn11 Xn F2 1 H2

(14.3)

In the aqueous environment of HF solutions, the Al atoms are replaced by O, F, or OH functional groups and hence the outer surfaces of the exfoliated MX layers are chemically terminated [11
14]. Thus, the interactions between the Mn11Xn layers become weak making their separation easy. Replacement of Al
M bond through hydrogen or van der Waals bonds allows delamination of MXene by the

MXene-based sensors and biosensors: next-generation detection platforms

363

ultrasonication of HF-treated MAX phases in suitable solvents such as isopropyl alcohol or methanol. This surface functionalization leads to significant impacts on the electronic and ion-transport properties of MXenes. The microscopic (scanning electron microscopic (SEM), transmission electron microscopic (TEM), high resolution TEM (HRTEM), selected area electron diffration (SAED) and spectroscopic (x-ray diffraction (XRD), Fourier transform infrared (FTIR)) characterization of 2D-layered MXene has been shown in Fig. 14.1(C
H) [6,10]. MXenes show variable electronic activity depending upon their functionalization [11]. Since their discovery in 2011, MXenes have gained significant attraction due to their unique layered structure and extraordinary catalytic properties. MXenes offer extremely exceptional chemical, electrical, and ion-transport properties that promise for a wide range of potential applications in various fields [15
17]. Recently, MXene has been applied as a sensitive platform for sensing and biosensing applications, which has been discussed in the present chapter. Moreover, future prospects in developing MXene-based detection devices have been focused at the end.

14.2

MXene-based sensing and biosensing for various analytes

MXene has emerged as a high-performance detection platform for various analytes. Sensing strategies based on MXene have been considered as highly advanced detection schemes with great utility in health, environment, medicine, and social security. Various analytical state-of-the-art methodologies have been developed exploiting unique sensing characteristics of MXene. Titanium carbide (Ti3C2) is the most explored MXene, which has been extensively applied for analytical sensing. The present section includes MXene-based detection of multiple analytes such as biomolecules, organic contaminants, using various analytical methods.

14.2.1 MXenes for detection of biomolecules Taking advantages of electrochemical techniques, different MXene sensors have been developed and exploited for sensing purposes which have been summarised as Table 14.1 [18
30]. MXene-modified electrodes have been reported to be effective transducers for immobilization of biological receptors (e.g., enzymes) onto its surface. MXene biosensors enhance the catalytic performances toward electrochemical determination of different biomolecules [18
24]. For example, nanocomposite of nafion-gold nanoparticles (Au-NP)-MXene was reportedly acted as a suitable surface for immobilization of glucose oxidase (GOx). The developed nafion-AuNPs-MXene biosensor was applied for amperometric detection of glucose [18]. In the developed biosensing matrix, MXene (Ti3C2Tx) showed improved electron-transfer reactions between active redox center (FAD) of GOx and electrode interface, showing direct electrochemistry between GOx and fabricated biosensor during glucose oxidation. Similarly, hemoglobin (Hb)-immobilized Ti3C2 was

Table 14.1 Electrochemical detection performance of MXene sensors and biosensors. Analyte

Electrochemical method

Detection limit

Detection range

References

Glucose H2O2 NO2 2 H2O2 H2O2 H2O2 AA, DA, UA, APAP H2O2 DA P53 gene Phenol Cd21, Pb21, Cu21, Hg21 BrO2 3 Malathion

Amperometry Amperometry Amperometry Amperometry Voltammetry (DPV) Amperometry Voltammetry (DPV)

5.9 µM 0.02 µM 0.12 µM 14.0 nM 1.95 µM 448 nM 0.25 µM, 0.26 µM, 0.12 µM, 0.13 µM 0.7 nM 100 3 1029 M 5 nM 12 nM 98 nM, 41 nM, 32 nM, 130 nM 41 nM 0.3 3 10214 M

0.1
18 mM 0.1
260 µM 0.5 µM
11.8 mM 0.1
380 µM 2 µM
1 mM 490 µM
53.6 mM Upto 750 µM

[18] [19] [20] [21] [22] [23] [23]


100 3 1029
50 3 1026 M 10 nM
1 mM 0.05
15.5 µM 0.1
1.5 µM

[24] [25] [26] [27] [28]

50 nM
5 µM 1 3 10214
1 3 1028 M

[29] [30]

Chronoamperometry FET ECL Amperometry Voltammetry (SWASV)

Voltammetry (DPV) Voltammetry (DPV)

DPV, differential pulse voltammetry; ECL, electrochemiluminescence; FET, field effect transistor; SWASV, square-wave stripping voltammetry.

MXene-based sensors and biosensors: next-generation detection platforms

365

explored for its mediator-free biosensing activity toward H2O2 [19] and NaNO2 [20]. The prepared Hb-nafion-MXene-modified glassy carbon electrode (GCE) sensor was successfully applied to study the direct electrochemistry between Hb and the working electrode using amperometry. Furthermore, nanocomposites of metal/ metal oxides nanoparticles and MXene have also been reported for sensing applications. Decoration of titanium oxide (TiO2) nanoparticles on Ti3C2-MXene biosensor was successfully performed and exploited for H2O2 detection using amperometry [21]. Furthermore, in a recent study, voltammetric sensor based on Ti3C2Tx-PtNPs/ GCE was reported, which was used for the detection of ascorbic acid (AA), dopamine (DA), uric acid (UA), and acetaminophen (APAP) biomolecules [23]. The sensor showed high electroactivity, which was ascribed to the synergistic effects of PtNPs and MXene. In another example, application of large anodic potential (1200 mV) to Ti3C2Fx resulted in the oxidation of its outer surface and utilized for oxidation studies of nicotinamide adenine dinucleotide (NADH) [23]. Furthermore, sensing of H2O2 was performed by exposing large cathodic potential (2500 mV) to Ti3C2Fx using chronoamperometry. The study showed great potential applicability of MXene-based biosensors, which exhibited dehydrogenase and oxidase-like activity suitable for sensing of NADH and H2O2, respectively. MXene-based field effect transistor (FET) sensor was developed for DA in spiked hippocampal neurons [25]. The conductance of Ti3C2Tx-MXene FET sensor was measured by ultrathin MXene micropatterns and different gating controls. The MXene sensor acted as an n-type FET when gate voltage was above 10.3 V and as p-type FET when gate potential level was below 10.3 V. The π
π interactions between DA and functionalized surface of MXene led to the efficient sensing of DA (Table 14.1). MXene-based quantum dots (MQDs) have also been utilized for bioimaging applications [31]. For example, Ti3C2-MQDs were synthesized and utilized as photoluminescent sensor. The prepared MQDs were applied as a biocompatible multicolor imaging probe for photoluminescent detection of RAW264.7 cell lines. Further, Ti3C2-MQDs were reported for sensing metabolism of MCF-7 cells [32]. Ti3C2-MQDs exhibited excitation wavelength due to size-dependant interband transition of carriers and surface defect sites. Furthermore, Ti3C2Tx was used as electroluminescent (ECL) sensor for the detection of nucleotide mismatch in human urine samples [26]. Practical applicability of the sensor for p53 gene single-nucleotide mismatch sensing showed high utility of MXene in biomedical applications.

14.2.2 MXene for detection of environmental contaminants MXenes have demonstrated promising applications toward environmental safety by the detection of potential contaminants. For example, Ti3C2-tyrosinase biosensor was used for the detection of phenol [27]. The MXene biosensor catalyzed the oxidation of phenol to corresponding o-quinone that was studied by amperometry. The biosensor showed high sensitivity toward phenol that was attributed to the highly compatible MXene surface, which retained tyrosinase activity even after its immobilization. Moreover, an alkaline (KOH) intercalated Ti3C2-MXene was prepared for voltammetric sensing of toxic heavy metals, using square-wave stripping voltammetry

366

Handbook of Nanomaterials in Analytical Chemistry

Figure 14.2 (A) Schematic preparation of Ti3C2 MXene from MAX phase and alkaline treatment, (B) SWASV response of the alk-Ti3C2/GCE sensor for individual analysis of (i) Pb21, (ii) Cd21, (iii) Cu21, (iv) Hg21; inset: corresponding linear calibration plots of peak current against Pb21, Cd21, Cu21, and Hg21concentrations, respectively [28]. Source: Reprinted with permission from X. Zhu, B. Liu, H. Hou, Z. Huang, K.M. Zeinu, L. Huang, et al., Alkaline intercalation of Ti3C2 MXene for simultaneous electrochemical detection of Cd(II), Pb(II), Cu(II) and Hg(II), Electrochim. Acta 248 (2017) 46
57.

MXene-based sensors and biosensors: next-generation detection platforms

367

(Fig. 14.2) [28]. Electroactivity of alk-Ti3C2/GCE was compared with pristine Ti3C2/GCE sensor toward detection of Cd21, Pb21, Cu21, and Hg21. Existence of [Ti-O]-H1 and [Ti-O]-K1 moieties in alk-Ti3C2 accelerated the cation exchange and thus the adsorption and reduction of heavy metal ions into their metallic form during stripping analysis. Furthermore, substitution of F2 ions with hydroxyl groups after alkaline treatment of Ti3C2 led to enhanced hydrophilicity and high conductivity for electron-transfer processes. Furthermore, a Ti3C2Tx/GCE sensor was prepared for the detection of bromate ions (BrO32). The sensor showed unique electrocatalytic properties toward BrO32 reduction using voltammetry [29]. In addition, MXene biosensors have been successfully applied for pesticide detection. An amperometric biosensor based on acetocholinesterase enzyme-immobilized Ti3C2Tx nanosheets was prepared for detection of organophosphate pesticide malathion [30]. The sensor showed high voltammetric performances toward malathion determination with low detection limit, high reproducibility, and stability. Furthermore, Ti3C2Tx-based surface-enhanced Raman spectroscopic (SERS) method was developed [33]. A SERS substrate based on Ti3C2Tx was prepared for Raman signal enhancement of dye Rhodamine 6 G, which is also a potent organic contaminant. The synergy between electromagnetic and chemical enhancements of Ti3C2Tx substrates showed high possibilities of MXenes in biochemical molecular sensing using SERS sensors. Ti3C2Tx demonstrated SERS effect in aqueous colloidal solutions of Rhodamine 6 G at 1027 M concentration.

14.2.3 MXene for detection of gaseous molecules MXene has been highly useful for the detection of toxic gases and applied as gas sensors. MXene can detect acetone (CH3COCH3) and ammonia (NH3), which are highly useful in medical diagnosis of diseases such as diabetes or peptic ulcers, respectively. MXenes show low electrical noise and strong signal intensity toward gaseous molecules. For example, Ti3C2OH2 MXene was used to study gases such as CH3COCH3, NH3, ethanol (C2H5OH), nitrogen oxide (NO2), propanal (C2H5CHO), and sulfur dioxide (SO2) at room temperature. The sensor exhibited a positive change in the resistance of the sensing channel over absorption of gases. The sensing response varied depending on the electronic properties of gases and semiconducting properties of the charge carrier (p- or n-type) [34]. Further, a Ti2CO2 MXene was prepared for NH3 sensing. Adsorption of various gases such as NH3, H2, CH4, CH3COCH3, CO2, N2, NO2, and O2 on Ti2CO2 surface was investigated to exploit its potential application as gas sensor. A significant change in the adsorption energy of MXene was observed with operating biaxial strain to capture NH3 molecules on its surface. The electronic interactions of NH3 with MXene resulted in the orbital overlap and large charge transfer. The conductivity of MXene was considerably enhanced after adsorption of NH3 under strain suggesting strong interaction and high sensitivity toward NH3 [35]. Moreover, MXene was further proved as a strong sensor for NH3 with high regenerating ability by reversible release and capture through control on the charge state of the system [36]. Introduction of two extra electrons to ZrCO2 resulted in the release of NH3 from MXene and led the conversion of chemisorption to physisorption. Furthermore,

368

Handbook of Nanomaterials in Analytical Chemistry

Figure 14.3 (A) Schematic illustration of Ti3C2Tx synthesis procedure, solution deposition at electrode and gas sensing equipment, (B) Ti3C2Tx-based sensing of ethanol, methanol, acetone, and ammonia gas at room temperature [10]. Source: Reprinted with permission from E. Lee, A.V. Mohammadi, B.C. Prorok, Y.S. Yoon, M. Beidaghi, D.J. Kim, Room temperature gas sensing of two-dimensional titanium carbide (MXene), ACS Appl. Mater. Interfaces 9 (2017) 37184
37190.

adsorption of NH3 on functionalized groups of Ti3C2Tx such as O2 or OH2 led to the generation of electrons, which minimized the concentration of charge on MXene film and thus increased the resistance of the device [10]. 2D sheets of Ti3C2Tx were prepared and were integrated on flexible polyimide platforms with solution casting method as shown in Fig. 14.3A. The Ti3C2Tx sensor showed a p-type behavior and successfully detected ethanol, methanol, acetone, and ammonia gas at room temperature (Fig. 14.3B).

14.2.4 MXene for detection of motion and physical stimuli In recent times, MXenes have been used as strain sensors due to their high sensitivity (GF B772.6) and tunable sensing range (30%
130% strain). MXenes have been applied for detection of phonations and substantial movements such as walking, jumping, running, or other human activities like coughing, and joint bending [37,38]. For example, Ti3C2Tx MXene nanocomposite with single-walled carbon nanotubes (CNTs) was prepared (Fig. 14.4A) and utilized as a strain sensor with

MXene-based sensors and biosensors: next-generation detection platforms

369

Figure 14.4 (A) Preparation of Ti3C2Tx/CNT sensor, (B) Ti3C2Tx/CNT nanocompositebased peizoresistive strain sensor for phonation and substantial movement detection; (i) Ti3C2Tx-MXene/CNT strain sensor attached to human throat, (ii
iv) responsive curves recorded while speaking “carbon”, “sensor”, and “MXene”, (v) Ti3C2Tx-MXene/CNT sensor attached to the human knee, (vi 2 viii) resistance responses of the sensor in detecting human leg movement walking, running, and jumping [37]. Source: Reprinted with permission from Y. Cai, J. Shen, G. Ge, Y. Zhang, W. Jin, W. Huang, et al., Stretchable Ti3C2Tx MXene/carbon nanotube composite based strain sensor with ultrahigh sensitivity and tunable sensing range, ACS Nano 12 (2018) 56
62.

detection limit as low as 0.1% [37] The nanocomposite strain sensor (Ti3C2Tx/ CNTs) was utilized as skin attachable wearable devices for real-time applications such as capturing physiological signal and motion monitoring (Fig. 14.4B). The tunneling distances between MXene layers and interconnected CNTs changed their overlapping areas and distances when external pressure was applied. Furthermore, a peizoresistive sensor based on Ti3C2 MXene was developed, in which the distance between two MXene interlayers was decreased when external pressure was applied [38]. The fabricated sensor was applied to human body such as on cheek, eye corner, and throat to study the physical stimuli such as cheek bulging, eye blinking, and throat swallowing. Moreover, knee-bending release movement was also monitored through change in current over the function of time. Thus, MXene sensor demonstrated peizoresistive behavior in detecting subtle human activities.

370

Handbook of Nanomaterials in Analytical Chemistry

14.2.5 MXene for terahertz sensing MXene materials have shown their great potential in terahertz (THz) sensing. Potential of MXenes as THz sensor was studied by performing density functional theory calculations on Ti3C2 [39]. In particular, optical properties of THz, the electronic band structures, and the thermoelectric figure of merit (ZT) of monolayer and stacked Ti3C2Tx were studied. Excellent light extinction and optical absorption was observed in Ti3C2 in the THz range (0.0012
0.012 eV). Furthermore, stacked Ti3C2-MXene exhibited superior THz absorption and a high ZT value sufficiently enough to be applied in THz detectors. Such extraordinary features enable MXene for their potential application in fabricating THz sensing devices, terahertz bolometers, and photothermoelectric detectors.

14.3

Conclusion

MXenes are a developing class of 2D materials, which are based on transition metal carbides, nitrides, or carbon nitrides. MXenes are produced by etching out A layer from a 3D structure consisting of MAX (Mn11AXn), where M is an early d-transition metal, A is the main group sp element, and X is C or N. MXenes are mechanically very strong materials composed of mostly M
C or M
N bonds. Chemical functionalization of the MXene surface is done with terminating groups such as O, F, and OH in order to be able to achieve chemical applications including sensing. MXenes have demonstrated promising features for sensing and biosensing applications. Titanium carbide is the most explored MXene in the field of sensing, and therefore exploitation of other transition metal-based MXenes is highly anticipated. High biocompatibility of MXene drives great motivation to design advance biosensing systems based on aptamers, antibodies, and protein molecules. However, achieving stability of MXene biosensors is of great challenge. Development of MXene-based wearable electronics contributes greatly to various healthcare diagnostics and environmental sensing applications. Overall, MXene materials hold multiple promising features to be applied in diverse sectors of technology. Thus, MXenes provide great enthusiasm toward their implementation as next-generation detection devices.

References [1] G.R. Bhimanapati, Z. Lin, V. Meunier, Y. Jung, J. Cha, S. Das, et al., Recent advances in two dimensional materials beyond graphene, ACS Nano 9 (2015) 11509
11539. [2] A. Sinha, Dhanjai, B. Tan, H. Zhao, J. Chen, R. Jain, MoS2 nanostructures for electrochemical sensing of multidisciplinary targets: a review, TrAC, Trends Anal. Chem. 102 (2018) 75
90.

MXene-based sensors and biosensors: next-generation detection platforms

371

[3] K. Huang, Z. Li, J. Lin, G. Han, P. Huang, Two-dimensional transition metal carbides and nitrides (MXenes) for biomedical applications, Chem. Soc. Rev. (2018). Available from: https://doi.org/10.1039/c7cs00838d. [4] C.M. Hussain, Handbook of Nanomaterials for Industrial Applications, Elsevier, 2018. [5] M. Naguib, V.N. Mochalin, M.W. Barsoum, Y. Gogotsi, MXenes: a new family of two-dimensional materials, Adv. Mater. 26 (2014) 992
1005. [6] M. Naguib, O. Mashtalir, J. Carle, V. Presser, J. Lu, L. Hultman, et al., Two dimensional transition metal carbides, ACS Nano 6 (2012) 1322
1331. [7] B. Anasori, Y. Xie, M. Beidaghi, J. Lu, B.C. Hosler, L. Hultman, et al., Two dimensional, ordered, double transition metals carbides (MXenes), ACS Nano 9 (2015) 9507
9516. [8] M. Naguib, M. Kurtoglu, V. Presser, J. Lu, J. Niu, M. Heon, et al., Two dimensional nanocrystals produced by exfoliation of Ti3AlC2, Adv. Mater. 23 (2011) 4248
4253. [9] A. Sinha, Dhanjai, H. Zhao, Y. Huang, X. Lu, J. Chen, et al., MXene: an emerging material for sensing and biosensing, TrAC Trends Anal. Chem 105 (2018) 424
435. [10] E. Lee, A.V. Mohammadi, B.C. Prorok, Y.S. Yoon, M. Beidaghi, D.J. Kim, Room temperature gas sensing of two-dimensional titanium carbide (MXene), ACS Appl. Mater. Interfaces 9 (2017) 37184
37190. [11] M. Khazaei, M. Arai, T. Sasaki, C.Y. Chung, N.S. Venkataramanan, M. Estili, et al., Novel electronic and magnetic properties of two-dimensional transition metal carbides and nitrides, Adv. Funct. Mater. 23 (2013) 2185
2192. [12] I.R. Shein, A.L. Ivanovskii, Graphene-like nanocarbides and nanonitrides of d metals (MXenes): synthesis, properties and simulation, Micro Nano Lett. 8 (2013) 59
62. [13] P. Paul, P. Chakraborty, T. Das, D. Nafday, T.S. Dasgupta, Properties at the interface of graphene and Ti2C MXene, Phys. Rev. B 96 (2017) 035437. [14] G.R. Berdiyorov, Effect of surface functionalization on the electronic transport properties of Ti3C2 MXene, Exploring Front. Phys. 111 (2015) 67002. [15] J. Zhu, E. Ha, G. Zhao, Y. Zhou, D. Huang, G. Yue, et al., Recent advance in MXenes: a promising 2D material for catalysis, sensor and chemical adsorption, Coord. Chem. Rev. 352 (2017) 306
327. [16] V.M.H. Ng, H. Huang, K. Zhou, P.S. Lee, W. Que, J.Z. Xu, et al., Recent progress in layered transition metal carbides and/or nitrides (MXenes) and their composites: synthesis and applications, J. Mater. Chem. A 5 (2017) 3039
3068. [17] J.C. Lei, X. Zhang, Z. Zhou, Recent advances in mxene: preparation, properties and applications, Front. Phys. 10 (2015) 107303
107311. [18] R.B. Rakhi, P. Nayak, C. Xia, H.N. Alshareef, Novel amperometric glucose biosensor based on MXene nanocomposite, Sci. Rep. 6 (2016) 36422. [19] F. Wang, C. Yang, C. Duan, D. Xiao, Y. Tang, J. Zhu, An organ-like titanium carbide material (mxene) with multilayer structure encapsulating hemoglobin for a mediatorfree biosensor, J Electrochem. Soc. 162 (2015) B16
B21. [20] H. Liu, C. Duan, C. Yang, W. Shen, F. Wang, Z. Zhu, A novel nitrite biosensor based on the direct electrochemistry of hemoglobin immobilized on MXene-Ti3C2, Sens. Actuat. B 218 (2015) 60
66. [21] F. Wang, C. Yang, M. Duan, Y. Tang, J. Zhu, TiO2 nanoparticle modified organlikeTi3C2 MXene nanocomposite encapsulating hemoglobin for a mediator free biosensor with excellent performances, Biosens. Bioelectron. 74 (2015) 1022
1028. [22] J. Zheng, J. Diao, Y. Jin, A. Ding, B. Wang, L. Wu, et al., An inkjet printed Ti3C2-GO electrode for the electrochemical sensing of hydrogen peroxide, J. Electrochem. Soc. 165 (2018) B227
B231.

372

Handbook of Nanomaterials in Analytical Chemistry

[23] L. Lorencova, T. Bertok, J. Filip, M. Jerigova, D. Velic, P. Kasak, et al., Highly stable Ti3C2Tx-(MXene)/Pt nanoparticles modified glassycarbon electrode for H2O2 and small molecules sensing applications, Sensors Actuat. B Chem. 263 (2018) 360
368. [24] L. Lorencova, T. Bertok, E. Dosekova, A. Holazova, D. Paprckova, A. Vikartovska, et al., Electrochemical performance of Ti3C2Tx MXene in aqueous media: towards ultrasensitive H2O2 sensing, Electrochim. Acta 235 (2017) 471
479. [25] B. Xu, M. Zhu, W. Zhang, X. Zhen, Z. Pei, Q. Xue, et al., Ultrathin MXene micropattern based field-effect transistor for probing neural activity, Adv. Mater. 28 (2016) 3333
3339. [26] Y. Fang, X. Yang, T. Chen, G. Xu, M. Liu, J. Liu, et al., Two-dimensional titanium carbide (MXene)-based solid-state electrochemiluminescent sensor for label-free single-nucleotide mismatch discrimination in human urine, Sens. Actuat. B 263 (2018) 400
407. [27] L. Wu, X. Lu, Dhanjai, Z.S. Wu, Y. Dong, X. Wang, et al., 2D transition metal carbide MXene as a robust biosensing platform for enzyme immobilization and ultrasensitive detection of phenol, Biosens. Bioelectron. 107 (2018) 69
75. [28] X. Zhu, B. Liu, H. Hou, Z. Huang, K.M. Zeinu, L. Huang, et al., Alkaline intercalation of Ti3C2 MXene for simultaneous electrochemical detection of Cd(II), Pb(II), Cu(II) and Hg(II), Electrochim. Acta 248 (2017) 46
57. [29] P.A. Rasheed, R.P. Pandey, K. Rasool, K.A. Mahmoud, Ultra sensitive electrocatalytic detection of bromate in drinking water based on Nafion/Ti3C2Tx (MXene) modified glassy carbon electrode, Sensors Actuat. B Chem. 265 (2018) 652
659. [30] L. Zhou, X. Zhang, L. Ma, J. Gao, Y. Jiang, Acetylcholinesterase/chitosan-transition metal carbides nanocomposites based biosensor for the organophosphate pesticides detection, Biochem. Engineer. J 128 (2017) 243
249. [31] Q. Xue, H. Zhang, M. Zhu, Z. Pei, H. Li, Z. Wang, et al., Photoluminescent Ti3C2 MXene quantum dots for multicolor cellular imaging, Adv. Mat. 29 (2017) 1604847. [32] X. Chen, X. Sun, W. Xu, G. Pan, D. Zhou, J. Zhu, et al., Ratiometric photoluminescence sensing based on Ti3C2 MXene quantum dots as an intracellular pH sensor, Nanoscale 10 (2018) 1111
1118. [33] A. Sarycheva, T. Makaryan, K. Maleski, E. Satheeshkumar, A. Melikyan, H. Minassian, et al., Two dimensional titanium carbide (MXene) as surface-enhanced raman scattering substrate, J. Phys. Chem. C 121 (2017) 19983
19988. [34] S.J. Kim, H.J. Koh, C.E. Ren, O. Kwon, K. Maleski, S.Y. Cho, et al., Metallic Ti3C2Tx MXene gas sensors with ultrahigh signal-to-noise ratio, ACS Nano 12 (2018) 986
993. [35] X. Yu, Y. Li, J. Cheng, Z. Liu, Q. Li, W. Li, et al., Monolayer Ti2CO2: a promising candidate for NH3 sensor or capturer with high sensitivity and selectivity, ACS Appl. Mater. Interfaces 7 (2015) 13707
13713. [36] B. Xiao, Y. Li, X. Yu, J. Cheng, MXenes: reusable materials for NH3 sensor or capturer by controlling the charge injection, Sens. Actuat. B 235 (2016) 103
109. [37] Y. Cai, J. Shen, G. Ge, Y. Zhang, W. Jin, W. Huang, et al., Stretchable Ti3C2Tx MXene/carbon nanotube composite based strain sensor with ultrahigh sensitivity and tunable sensing range, ACS Nano 12 (2018) 56
62. [38] Y. Ma, N. Liu, L. Li, X. Hu, Z. Zou, J. Wang, et al., A highly flexible and sensitive piezoresistive sensor based on MXene with greatly changed interlayer distances, Nat. Commun. 8 (2017) 1207. [39] Y.I. Jhon, M. Seo, Y.M. Jhon, First-principles study of a MXene terahertz detector, Nanoscale 10 (2018) 69
75.

Functionalized nanomaterials for sample preparation methods

15

Erkan Yilmaz1,2 and Mustafa Soylak3 1 Faculty of Pharmacy, Department of Analytical Chemistry, Erciyes University, Kayseri, Turkey, 2Nanotechnology Research Center (ERNAM), Erciyes University, Kayseri, Turkey, 3 Faculty of Sciences, Department of Chemistry, Erciyes University, Kayseri, Turkey

Abbreviations [C8MIM][PF6] Acryloyl-β-CD AFB1 APTES BPEI C16mimBr C60 CNTs DCC DESs d-SPE EDTA EDXRF ETAAS FAAS FIA FT-IR G GC GC
FID GC
MS/MS GO HPLC HR-CS-ETAAS ICP-AES ICP-OES ILs LC
UV LOD LOQ MAA

1-octyl-3-methylimidazolium hexafluorophosphate acryloyl-β-cyclodextrin aflatoxin B1 3-aminopropyltriethoxysilane polyethyleneimine 1-hexadecyl-3-methylimidazolium bromide fullerenes carbon nanotubes N,N-dicyclohexylcarbodiimide deep eutectic solvents dispersive solid-phase extraction N-(trimethoxysilylpropyl) ethylenediamine triacetic acid energy dispersive X-ray fluorescence spectrometry electrothermal atomic absorption spectrometry flame atomic absorption spectrometer flow injection analysis Fourier-transform infrared spectroscopy graphene gas chromatography gas chromatography
flame ionization detection gas chromatography
tandem mass spectrometer graphene oxide high-performance liquid chromatography high-resolution continuum source electrothermal atomic absorption spectrometer inductively coupled plasma atomic emission spectrometry, inductively coupled plasma optical emission spectrometer ionic liquids liquid chromatography
ultraviolet spectrophotometer limit of detection limit of quantification methacrylic acid

Handbook of Nanomaterials in Analytical Chemistry. DOI: https://doi.org/10.1016/B978-0-12-816699-4.00015-3 Copyright © 2020 Elsevier Inc. All rights reserved.

376

Handbook of Nanomaterials in Analytical Chemistry

MALDI
MS MIPs MOFs MNPs MWCNTs MWCNTsCOOH NADESs ND NMs NPs PAHs PAN PANI PDMS PF PT-SPE RSD SEM SPE SPME SWCNTs TAR TEM TMSPDETA TMSPEDA TSP-MS-MS XPS α-ZOL β-ZAL β-ZOL

15.1

matrix-assisted laser desorption/ionization mass spectrometer molecularly imprinted polymers metal
organic frameworks metal nanoparticles multiwalled carbon nanotube carboxylated multiwalled carbon nanotubes natural deep eutectic solvents nanodiamond nanomaterials nanoparticles polycyclic aromatic hydrocarbons 1-(2-pyridylazo)-2-naphtol polyaniline polydimethylsiloxane preconcentration factor pipette-tip solid-phase extraction relative standard deviation scanning electron microscopy solid-phase extraction solid-phase microextraction single-walled carbon nanotubes 4-(2-thiazolylazo)resorcinol transmission electron microscopy N1-(3-trimethoxysilylpropyl) diethylenetriamine N-(3-trimethoxysilylpropyl) ethylenediamine thermospray tandem mass spectrometer X-ray photoelectron spectroscopy α-zearalenol β-zearalanol β-zearalenol

Introduction

An important sentence “There is a lot of space down there,” by R. Feynman in 1959, took its place in the history as the first step of nanotechnology. At that time, it was unpredicted that there would be such advanced technological development in this field [1,2]. In general, materials in particle size ranging from 10 to 100 nm are classified as nanomaterials (NMs). Because of the different physical and chemical properties of NMs, according to the micro-sized and bulk materials, NMs appear in almost every field—from chemistry to biology, medicine to agriculture, electronics to biotechnology, and food industry to pharmacology [3
5]. Surface energy of small particles and higher surface atoms fraction lead to these unexpected features when compared with micro-sized and bulk materials. High surface atoms fractions that lead to high surface-area-to-volume ratio of NMs are one of the most important features. This situation is related to the presence of more

Functionalized nanomaterials for sample preparation methods

377

active atoms in the NMs. These more active atoms in the NMs are the most important driving force causing specific affinity and interaction with different free atoms, molecules, and ions [6
10]. High surface area of NMs and special interactions between NMs and different species (atoms, molecules, and ions) lead to high adsorption capacity for different organic, inorganic, and bioactive species [11
13]. NMs also provide easy functionalization and reusability, improved electronic properties, such as high conductivity, fast response to physical event, and chemical reactions. Due to these unique features, NMs have taken their place among the most preferred materials in various branches of analytical chemistry, such as sample preparation methods, separation techniques, and qualitative and quantitative analyses [11
14]. In the last few decades, undoubtedly, the most important turning point in the change and development of analytical and bioanalytical sciences has been the use of NMs as sorbent in solid-phase extraction (SPE)/microextraction (SPME)-based sample preparation methods, column filler material in chromatographic systems [high-performance liquid chromatography (HPLC), liquid chromatography (LC)
mass spectrometry (MS), gas chromatography (GC)
MS, LC
tandem mass spectrometer (LC
MS/MS), etc.], substrate in detection system, and sensing agent in sensor and biosensor systems [15
21]. NMs can mainly be classified on the basis of dimensionality and chemical form of materials, which is explained in Fig. 15.1, and can also be classified according to different criteria, such as dimensionality, morphology, composition or uniformity, and agglomeration state [22]. An alternative, complementary classification may divide nanoparticles (NPs) into two main groups, namely, organic and inorganic, according to their chemical composition. While carbonaceous and polymeric materials are classified as organic NMs, metallic and metal-oxide NMs are classified as inorganic NMs. The main reason for the frequent use of NMs in sample preparation and analysis procedures that form the basis of analytical chemistry is that they can be modified by using different functionalization agents. Modification of NMs with different groups and species provides advantages, such as high affinity and adsorption capacity, against the analytes’ high enrichment factors (EFs), accelerating the adsorption and desorption steps in the separation- and preconcentration-based methods. In addition, it also offers advantages such as improved separation efficiency, easier dispersibility in the liquid phases, low detection limit, fast response time, and selective response signal for chromatographic, spectroscopic, sensor- and biosensorbased separation, and analysis techniques [23
28]. The most commonly used methods in the production and functionalization of NMs are as follows [29
40]: 1. 2. 3. 4.

coprecipitation, reduction or oxidation, solvothermal or hydrothermal procedure, chemical vapor deposition,

378

Handbook of Nanomaterials in Analytical Chemistry

Figure 15.1 Classification of nanomaterials attending to dimensionality and chemical forms. 5. 6. 7. 8. 9. 10. 11.

physical vapor deposition, electrospinning, thin film formation, surface coating, immobilization, impregnation, sol
gel,

Functionalized nanomaterials for sample preparation methods

12. 13. 14. 15. 16.

379

discharge method, laser vaporization, laser ablation, electrochemical polymerization and in situ polymerization.

15.2

Functionalized nanomaterials for sample preparation methods

15.2.1 Carbon-based nanomaterials Carbon-based NMs have been the most commonly used materials in all disciplines, such as energy, chemistry, medicine, health, biotechnology, and pharmacy, since the discovery of fullerene (C60) in 1985 and carbon nanotubes (CNTs) in 1991 [41
43]. In particular, carbon-based NMs [e.g., fullerenes, CNTs, carbon nanofibers, carbon nanocones graphene, graphene oxide (GO), carbon nanodisks, nanohorns] and their functionalized forms have been preferred as a sorbent in many SPE/SPME methods [44
48]. The SPE/SPME methods based on carbon-based functionalized NMs are frequently used for the separation and preconcentration of trace amounts of organic, inorganic, and bioactive species in environmental, water, biological, food, and pharmaceutical samples. Moreover, these are among the most researched materials of the 21st century. Fullerenes are soccer ball
shaped polyhedral NMs obtained by the coiling of the graphene together. C60, C70, C240, C540, and C720 isomers of fullerenes can be obtained by using more carbon atoms. C60 as the most used isomer has a diameter of approximately 1 nm. A carbon atom in fullerene is bonded to three carbon neighbors by sp2 hybridization in five- to six-membered rings arranged as 20 hexagons and 12 pentagons [49,50]. CNTs are produced by rolling up graphite sheets into nanoscale tubes [i.e., single-walled CNTs (SWCNTs)] or with additional graphite tubes wrapped around the cores of the first layer of roll of graphite sheets. They are classified as SWCNTs, double-walled CNTs (DWCNTs), and multiwalled CNTs (MWCNTs). After the discovery of these special nano-carbons, scientists focused on the different applications because of their excellent surface structure, high surface area, and unique mechanical, chemical, and thermal stability. A carbon atom in CNTs is bonded to three carbon neighbors by sp2 hybridization and has π
π bonds between carbon atoms. Hence, CNTs can establish π
π and van der Waals interactions with atoms, ions, and molecules. These unique properties have made CNTs one of the most widely used adsorbents in SPE/SPME applications. Though SWCNTs, DWCNTs, and MWCNTs are produced from the same carbon source, they show very different adsorption performances because of their different numbers of graphite sheets [51
53]. Nanodiamond (ND) is also a commonly used nano-carbon in laboratory and industry scale due to its unique chemical, mechanical, and physical features, such

380

Handbook of Nanomaterials in Analytical Chemistry

as high surface area, high resistivity to corrosive chemicals, very high hardness, high biocompatibility, high thermal conductivity, and low friction coefficient. Hence, NDs are preferable materials in SPE/SPME applications [54,55]. Graphene (G) and GO are innovative nano-carbons that marked this century and are called the “mother” of all graphitic carbon materials [56,57]. Graphene fabricated in 2004 has been recorded in the literature as a material that has given its inventor a Nobel Prize. When compared with CNTs, fullerenes, NDs, carbon nanofiber, and other carbon-based NMs, graphene and GO provide more effective and attractive performance for sorption-based sample preparation methods due to their unique properties, such as improved nanosheet morphology, very effective π
π interactions toward to analytes especially carbon-based ring structures, and very high specific surface area (i.e., a theoretical value of 2630 m2 g21), which lead to high adsorption capacity for analytes [58
60]. In 2004 carbon dots (carbon quantum dots or C-dots) were recognized by accident while separating SWCNTs from carbon soot using gel electrophoresis. C-dots have been classified as star of nano-carbon allotropes. They gained important interest by scientists due to their effective and preferable properties, such as simple and cheap production with high quantities, great biocompatibility, and excellent optical property. C-dots mainly consist of sp3 and sp2 carbon atoms. Hence, they have a similar structure with graphenic nanosheets, 2D graphene, and 1D CNTs. Although C-dots have been widely used in many areas, such as electronic, bioimaging, and optical application, they are already being used in sample preparation applications [61,62].

15.2.1.1 Functionalization of carbon-based nanomaterials 15.2.1.1.1 Covalent functionalization of carbon-based nanomaterials Although all the nano-carbon allotropes described above contain unique properties, the most important properties of them are that they are functionalized by covalent or noncovalent functionalization methods in order to use the desired properties for many applications. The covalent functionalization can be carried out by direct covalent sidewall functionalization with the molecule of interest or by indirect covalent functionalization with carboxylic groups previously introduced on their surface. In many literature studies, it is observed that the covalent functionalization reactions are majorly used procedures consisting of oxidization, hydrogenation, halogenation, cycloaddition, nucleophilic addition, and radical addition. By using these functionalization reactions, a linkage between the carbon skeleton of NMs and the functional groups is formed. As mentioned above, these modifications can occur by direct sidewall functionalization with aid of silanized groups located on the surface of the carbon NMs or indirect functionalization with carboxylic groups located on the defects of the carbon NMs [63
65]. The main disadvantage of covalent functionalization is that the well-organized carbon structure of NM is disturbed, which cause significant changes in their valuable physical or chemical features.

Functionalized nanomaterials for sample preparation methods

381

In the covalent functionalization, carbon-based NMs are generally oxidized by using strong acids, such as H2SO4 and HNO3, at high temperature. In this way,
COOH,
OH, and
C 5 O
groups are introduced in their structure [63
65]. The NMs have
COOH,
OH, and
C 5 O
groups that can be used directly or modified with desired functional groups by different substitution reactions. After oxidation, these NMs have zero net charge, and “point of zero charge” or “isoelectric point” is formed for these NMs, that is, the surface charges of these oxidized NMs vary with the ambient pH values. When the pH value of sample solutions is reached to values higher than “point of zero charge” or “isoelectric point,” the surface of oxidized NMs has gained negatively charged. In this case, cationic species, such as metal ions, cationic surfactants, and organic compounds, which have positive charge, can be adsorbed on the surface of NMs by electrostatic interactions. Around point-of-zero-charge region, the surface of oxidized NMs has neutral charge. In this case, van der Waals interactions and hydrogen bonding are formed between NM and neutral species, such as metal
ligand complex and organic compounds. On the contrary, at lower pH values than the point of zero charge, there is a competition between protons and cations for the same sites on oxidized NMs, which cause a decrease in the adsorption. For example, metal ions can be adsorbed on the oxidized surface of NMs at high pH value and eluted by using acidic solutions. Hence, the pH value of solution medium is important and needs optimized factor in SPE/SPME studies. Moreover, oxidation process leads to the formation of holes in the NMs. In this manner, inorganic and organic species in solution phase can be entered into these holes and retained. SPE methods are generally used in the separation and enrichment of trace analytes found in aqueous media. Therefore dispersion of sorbents in the aqueous phase is one of the most critical processes. As the hydrophobic properties of the pristine carbon NMs are dominant, it is very difficult to disperse in the aqueous medium. In this way the modification results in a significant increase in extraction efficiency by allowing the NMs to be dispersed easily in the aqueous medium. In general, functionalized CNTs are easier to disperse than the corresponding pristine materials, therefore facilitating their characterization and purification. In many cases the oxidation is just the previous step to the immobilization of different molecules. Covalent modification of NMs with complexing agents, organic compounds, polymers, and extraction solvents has an important place in SPE/SPME applications. Some examples of the applications of oxidized and covalent-modified carbon-based NMs for adsorption-based separation and enrichment studies in the literature are explained later. Sun et al. prepared carboxylated MWCNTs (MWCNTs-COOH) as dispersive SPE (d-SPE) sorbent for the separation and preconcentration of trace amounts of pyrethroid pesticides prior to their GC
electron capture detector (ECD) detections. They optimized the d-SPE method and used seven pyrethroid pesticides at trace level in carrot cucumber, tomato, eggplant, and spinach samples for analysis. The d-SPE/GC
ECD procedure provided high extraction efficiency between 88.5% and

382

Handbook of Nanomaterials in Analytical Chemistry

108.2%, low limit of detection (LOD) (0.5
2.9 μg kg21), and limit of quantification (LOQ) (1.5
9.7 μg kg21) values [66]. Lo´pez-Feria et al. checked the applicability of MWCNTs and carboxylated SWCNTs (SWCNTs-COOH) for SPE of atrazine, chlortoluron, simazine, diuron, terbuthylazin-desethyl, malathion parathion and dimethoate pesticides at trace level in virgin olive oil samples. They filled 30 mg of CNT sorbents in a cartridge to prepare SPE system. Analytes sorbed on the CNTs were eluted with 500 μL of ethyl acetate, and the eluent volume was evaporated until 50 μL by nitrogen stream. Concentrations of analytes were analyzed with the GC
MS method. They used these prepared SPE column system at least 100 times, which performed successfully every time. The developed procedure provides LOD between 1.5 and 3.0 μg L21 [67]. Sun et al. used carboxylated SWCNT fibers as a SPME sorbent for the separation and preconcentration of many chlorophenols (CPs) and organochlorine pesticides (OCPs) in aqueous samples followed by GC
ECD detections. They used sol
gel-coating procedure to fabricate carboxylated SWCNT fibers. In this procedure a sol
gel solution was prepared by mixing 120 mg of TSO-OH, 200 μL of dichloromethane, 150 μL of tetraethyl orthosilicate (TEOS), 15 mg of methylhydrosiloxane (PMHS), 80 μL of trifluoroacetic acid (TFA), and 5% of water. Next, the sol
gel coating was formed on the outer surface of the fused-silica fiber by vertically immersing fiber into the prepared sol
gel solution, and then the fiber was left to interact with the carboxylated SWNTs in dichloromethane solution. The carboxylated SWCNT fibers were dried before SPE application. The carboxylated SWCNT fibers showed more effective sensitivity and selectivity than commercial SPME fibers. The SPME/GC
ECD procedure was applied to analyze CPs and OCPs in lake and wastewater samples, with high recovery results (89.7%
101.2%) [68]. Kueseng and Pawliszyn fabricated a MWCNTs-COOH/polydimethylsiloxane (MWCNTs-COOH/PDMS)
coating thin film as a new 96-blade SPME system for trace amount of phenolic compounds prior to HPLC
ultraviolet (HPLC-UV) determination. In this synthesis procedure, MWCNTs-COOH particles (5%, w/w of PDMS) were dispersed in dichloromethane solution by sonication for 3 min. Then, 3 g of PDMS prepolymer was added into the solution including MWCNTs-COOH and sonicated for 5 min to disperse into the prepolymer. Next, the coating procedure was carried out by immersing of 2 cm portions of each pin into the MWCNTsCOOH/PDMS mixture for 5 s. The coated blade was cured in an oven at 150 C. The extraction and analysis procedure provided acceptable extraction performance between 64% and 90% with relative standard deviation (RSD) # 6% and low LOD between 1 and 2 μg L21. Moreover, when compared with traditional methods, the MWCNTs-COOH/PDMS 96-blade SPME apparatus has better performance, such as simple and easy applicability, cheap and easy coating procedure, and high reusability (minimum 110 extraction application) [69]. Kou and Liang carried out a comparative SPE method for the separation and preconcentration of trace amounts of bisphenol and tetrabromobisphenol A prior to LC
MS
MS determinations. For this purpose, they compared SPE performances

Functionalized nanomaterials for sample preparation methods

383

of MWCNTs, carboxyl-functionalized MWCNTs, and fullerenes and decided to use carboxyl-functionalized MWCNTs as sorbent. They applied the developed SPE method for determining trace amounts of bisphenol and tetrabromobisphenol A in lake water and sea water samples with good recoveries between 82% and 99% with the RSD , 5.0% [70]. Chang et al. introduced a microwave-assisted surface functionalization method to obtain carboxyl and carbonyl-modified diamond NPs. In this synthesis procedure, diamond nanopowders were added into an oxidized acid solution consisting of HNO3 and H2SO4 (1:3, v/v), and the mixture was irritated by microwave radiation at 100 W power. The temperature was set to 100 C and was applied for 3 h. In the polyarginine-coated diamond NP preparation step, an 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC)-mediated coupling reaction was used as follows: carboxyl-modified diamond NPs were mixed with a solution containing EDC (22 mg mL21, 63.7 μL), polyarginine (4 mg mL21, 155 μL), and H3BO3/NaOH buffer (5 mM, pH 8.5). The mixture was shaken gently for 2 h at room temperature and the prepared polyarginine-coated diamond NPs were washed and dried. The new sorbent was used for the extraction of phosphorylated peptides from complex samples and selective preconcentration of multiphosphorylated peptides prior to direct matrix-assisted laser desorption/ionization (MALDI)
time-of-flight (TOF) mass-spectrometric detections. The new sorbent has shown an effective affinity for multiphosphorylated peptides because of the multiple arginine
phosphate interactions. The developed method provided the analysis of 50 μL of sample containing nonfat milk, α-casein, and r-casein at a concentration as low as 1 3 1029 M [71]. Similar synthesis method was used for the fabrication of polylysine-coated diamond NMs as sorbent for the separation, preconcentration, and digestion of DNA oligonucleotides in one microcentrifuge tube prior to MALDI-TOF mass-spectrometric analysis (MS) [72]. Kong et al. fabricated carboxylated/oxidized diamond NPs by oxidizing them and using them for the extraction and analysis of proteins followed by MALDI-TOF mass-spectrometric (MS) analysis [72]. Silane groups, such as (3-aminopropyl)triethoxysilane (APTES), (3-chloropropyl)-trimethoxysilane, N-(3-trimethoxysilylpropyl) ethylenediamine (TMSPEDA), N1-(3-trimethoxysilylpropyl) diethylenetriamine (TMSPDETA), and 3methacryloxypropyltrimethoxysilane, are frequently used as coupling agent for covalent modification of NMs. Many desired functional groups are covalently attached to NMs via these silane groups [73
77]. Sua´rez et al. immobilized carboxylated SWCNTs (COOH-SWCNTs) onto porous glass in a different SPE application. In the synthesis procedure, they oxidized SWCNTs with 20 mL of H2SO4:HNO3 (3:1) solution by using ultrasonic irritation (50 W, 60 Hz) for 90 min. Then, the obtained carboxylated SWCNT particles were washed with ultrapure water and dried. In order to obtain silanized glass surface, cleaned glass sample was mixed with a known volume of 3-amino propyl triethoxy silane and 0.05 M mL ammonium acetate (pH 5.0) and heated at 80 C in a water bath for 2 h. After this reaction time, the mixture was filtered on 0.45 μm filters, washed and dried at 95 C. Next, the obtained silanized glass was added into a solution including 0.6 mL of glutaraldehyde and 5 mL of 0.1 M orthophosphate at

384

Handbook of Nanomaterials in Analytical Chemistry

pH 8.5 and was mixed until the completion of reaction. In the last step, the obtained activated glass and COOH-SWCNTs were mixed together in a 3 mL dimethylformamide solution containing 0.7 mg of 1,3-dicyclohexylcarbodiimide for 5 h. The prepared COOH-SWCNT-modified glass was washed, dried, and characterized by atomic and electron microscopy methods [73]. Lv et al. modified GO and silica particles with three different kinds of silane coupling agents, including APTES, 3-methacryloxypropyltrimethoxysilane, and (3-chloropropyl)-trimethoxysilane. The functionalized materials were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and Zetasizer Nano ZSP. The authors used these new materials for ultrasonic-assisted d-SPE of sulfamerazine and sulfameter. The obtained results showed that the (3-chloropropyl)-trimethoxysilane-modified GO had a good and better sorption and extraction performance than other materials for the separation and preconcentration of sulfonamides in milk samples with high extraction efficiencies between 92.16% and 103.81% and RSDs lower than 3.20%. After d-SPE, concentrations of analytes were measured with HPLC [74]. Sitko et al. prepared aminosilanized GO (GO-NH2) by modifying GO with APTES for selective preconcentration of Pb(II) ions. In the synthesis procedure, the authors used Hummers’ method for fabrication of GO. The obtained GO particles were added into anhydrous ethanol and dispersed. Then, 10 mL of APTES was added to the suspension and the mixture was heated at 70 C for 4 h. The obtained aminosilanized GO material was characterized by SEM, Raman, x-ray diffractometer (XRD), and X-ray photoelectron spectroscopy (XPS) methods. Pb(II) ions were adsorbed on the surface of GO-NH2-like complex formation. After dispersive micro-SPE step, Pb(II) ions sorbed on the GO-NH2 material were measured directly by injecting the suspended GO-NH2 into graphite tube for electrothermal atomic absorption spectrometry (ETAAS). Modification of GO with APTES provided excellent dispersibility in aqueous samples, which lead to very effective interaction with Pb(II) ions with very fast adsorption. The developed method provided low LOD of 9.4 ng L21 and high preconcentration factor of 100 [75]. Huang et al. used a hydrothermal synthesis procedure to modify graphene with APTES. The fabricated graphene-APTES material was used for SPE of polycyclic aromatic hydrocarbons (PAHs) at trace level in environmental water samples prior to HPLC determinations. The authors used only 10 mg of sorbent for the separation and preconcentration of PAHs traces from 100 mL of sample solution due to high surface area and high adsorption capacity of NMs. The developed method provided high extraction efficiency changing from 84.6% to 109.5% for PAHs [76]. In a different application, GO was modified with APTES, TMSPEDA, and TMSPDETA. These three different obtained materials were used for selective SPE of hexavalent chromium traces at pH 3.5. The amount of amino silanes attached to GO decreases in the order of APTES . TMSPEDA . TMSPDETA. Hence the APTES-modified GO was used for selective and sensitive SPE of Cr(VI) ions prior to low-power energy dispersive X-ray fluorescence spectrometry (EDXRF) analysis. The method was used for the analysis of Cr(VI) in water samples with recoveries of 99.7 6 2.2 [77].

Functionalized nanomaterials for sample preparation methods

385

Xiao et al. prepared a new coating material, polymeric fullerene, for modifying the fibers in SPME apparatus. The obtained SPME apparatus was used in the headspace SPE method for the separation and preconcentration of naphthalene congeners, benzene, toluene, ethylbenzene and xylene (BTEX), and phthalic acid diesters in water samples. Concentrations of analytes in the last phase were measured by GC
flame ionization detection (FID) detection system [78]. In a different application, polysilicone fullerene
coating material was prepared for SPME and determination of trace amounts of semivolatile compounds. fullerene polymers was fabricated by the reaction of excess of fullerene (C60) with ω-azido-undecyl-polymethylsiloxane in reflux system. Then, the prepared PF was coated on the commercial PDMS of 100 μm thickness. When compared with the PDMS, the new fibers showed better sensitivity, selectivity, and extraction performance; thermal stability; and life span [78]. Yu et al. used sol
gel method to fabricate hydroxyfullerenecoated SPME fiber. Fullerol (fullerene polysiloxane) was prepared by the reaction of C60 with aqueous NaOH and H2O2 in the presence of tetrabutylammonium hydroxide. They used IR and SEM methods for the characterization of new material. The prepared headspace SPME apparatus was used for the separation and preconcentration of polar aromatic amines, PAHs, and polychlorinated biphenyls prior to GC
FID and GC
electron capture detection [79]. Vallant et al. prepared aminosilica-modified fullerene for SPE of proteins, peptides, and flavonoids with recoveries of B99%. In the production of sorbent, fullerenoacetic acid and epoxyfullerenes were reacted with (aminopropyl)trimethoxysilane in the reflux system [80]. Vallant et al. synthesized dioctadecyl methano fullerene, fullerenoacetic acid, and iminodiacetic acid fullerene materials from pristine fullerene by using different chemical reactions. The new materials were used for the extraction and preconcentration of serum compounds prior to MALDI
MS/MS analysis [81]. Complexing agents, such as 5-aminosalicylic acid, 4-(2-thiazolylazo)resorcinol (TAR), 8-hydroxyquinoline, eriochrome black T, 1-(2-pyridylazo)-2-naphthol, dithizone, 1,5-diphenylthiocarbazone, ethylenediamine, (5-bromo-2-pyridylazo)-5(diethylamino)phenol, 1-(2-thiazolylazo)-2-naphthol, 1-(2-pyridylazo)-2-naphthol, and ethylenediaminetetraacetic acid, are frequently used for selective retention of trace heavy metal ions on the sorbent surface. It has been reported in many studies that the extraction efficiencies and adsorption capacities of heavy metal ions increased with the nonreversible covalent modification of the surfaces of NMs with these complexing agents [82
90]. Soliman et al. fabricated 5-aminosalicylic acid
modified MWCNTs by covalent immobilization [82]. In the fabrication procedure, pristine MWCNTs were converted to MWCNTs-COOH by a well-known oxidization method. Pristine MWCNTs were reacted with a concentrated mixture of H2SO4/HNO3 in an ultrasonic bath at 55 C for 7 h, and the obtained MWCNTs-COOH particles were washed with ultrapure water and dried in an oven. In the second step, N,N-dicyclohexylcarbodiimide (DCC) was used to link MWCNTs-COOH particles to 5aminosalicylic acid. For this purpose, 2 mmol of 5-ASA (amino salicylic acid), 2.0 g of DCC, and 2.0 g of MWCNTs-COOH were mixed in dimethylformamide (DMF) solution, and the obtained mixture was stirred for 48 h at room temperature.

386

Handbook of Nanomaterials in Analytical Chemistry

The fabricated MWCNTs-5-ASA material was characterized by scanning electron microscope, FT-IR spectroscopy, and surface coverage determination and was used for the separation and preconcentration of Pb(II) traces prior to inductively coupled plasma optical emission spectrometry (ICP-OES) analysis. Trace Pb(II) ions in aqueous sample solution (pH 4.0) were preconcentrated on 50 mg of the new fabricated sorbent and eluted with 4.0 mL of 2 M HNO3. After optimization step, the developed SPE method was applied to water samples [82]. In a different complexing agent immobilization procedure, Madadizadeh et al. produced 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol-modified MWCNTs in two steps [83]. Pristine MWCNTs were first oxidized with concentrated HNO3 and then reacted with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol in a reflux system. The prepared sorbent was used for SPE of trace amount of Cd(II) ions followed by ETAAS determination. Preconcentration factor, LOD, and RSD values for Cd(II) ions were found as 300, 0.14 ng L21, and 6 3.6%, respectively. The developed SPE-ETAAS procedure was used for the analysis of cadmium in different water samples [83]. Tajik and Taher used similar oxidization and complexing agent modification reactions to link 1-(2-pyridylazo)-2-naphtol (PAN) on the surface of MWCNTs. The prepared PAN-MWCNT sorbent was used for the separation and preconcentration of Zn(II) ions in aqueous sample solutions (pH 5) prior to its flame atomic absorption spectrometer (FAAS) analysis. Preconcentration factor, LOD, and RSD values for Zn(II) ions were found as 250, 0.07 pg mL21, and 6 1.2%, respectively. The suggested method was successfully applied to biological and water samples [84]. A different research group prepared PAN-modified MWCNTs with similar covalent modification method and used it as a sorbent for SPE of Co(II) ions at trace level [85]. Moghimi and Siahkalrodi modified graphene material with N-methyl-glycine and 3,4-dihydroxybenzaldehyde by using a reflux synthesis unit. The prepared material was used as a sorbent for selective SPE of Pb(II) ions. After SPE stage, the concentration of lead in eluent phase was measured with FAAS [86]. Madadrang et al. linked ethylenediamine triacetic acid (EDTA) on the GO surfaces through a silanization reaction between N-(trimethoxysilylpropyl) ethylenediamine triacetic acid (EDTA-silane) and hydroxyl groups on GO surface. The new sorbent has shown selective sorption properties for Pb(II) ions at pH 6.8 [87]. Pytlakowska et al. prepared 2,20 -iminodiacetic acid
modified GO sorbent for the separation and preconcentration of Pb(II), Zn(II), Cu(II), and Cr(III) traces from water samples by applying dispersive micro-SPE procedure. Their modification method is based on the nucleophilic substitution of dimethyl-2,20 -iminodiacetate hydrochloride to the surface of GO. Heavy metal ions preconcentrated on the sorbent at pH 6.5 were analyzed by EDXRF. The adsorption capacities of new sorbent were found as 108.4, 117.1, 80.7, and 119.6 mg g21 for Cu(II), Cr(III), Pb(II), and Zn(II) ions, respectively [88]. Zhao et al. prepared two different complexing agents (single- and double-arm amide
thiourea) and used them for covalent modification of ND particles. These two sorbents were used for selective sorption of uranium ions. In the functionalization method the synthesized single-arm or double-arm amide
thiourea complexing

Functionalized nanomaterials for sample preparation methods

387

agent was reacted with oxidized NDs in a reflux system. The obtained results showed that the prepared two sorbents have very fast adsorption kinetics for uranium (equilibrium time: 2 min), high adsorption capacities (B200 mg g21), and great selectivities for uranium (between 72% and 82%) [89]. In a different application, MWCNT was oxidized and chemically functionalized by 3-hydroxy-4-((3-silylpropylimino) methyl) phenol to produce an effective sorbent for SPE of Fe31, Cu21, Zn21, Ni21, Co21, and Pb21 ions [90]. Polymeric nanocomposites consisting of inorganic NPs and organic polymers are a new strategy to obtain innovative materials that provide desired properties, and these nanocomposites show better performance than their microparticle counterparts and might lead to improved physical and chemical properties. Modification of NMs with polymers might provide selective extraction of analyte(s) and high adsorption capacities for analytes due to their highly branched structure that consists of many reactive organic functional groups, well-ordered three-dimensional (3D) molecular configuration, and large internal and external surfaces. Moreover, they provide high chemical stability toward corrosive solutions, such as H2SO4 and HNO3, and high thermal stability for thermal desorption stages in SPE/SPME applications [91
98]. Modification of carbon NMs with different polymers as covalent is an important task for the fabrication of SPE/SPME sorbents. These reactions are called polymergrafting reactions and can be carried out by two different ways: (1) high reactive polymers can react directly with NMs, which have a bonding agent, such as carboxy, amine, silane, and hydroxy functional groups. (2) NMs, which have bonding agents, such as carboxy, amine, silane, and hydroxy functional groups, act as a polymer initiator with a monomer M1, and, in a second step, copolymerization with a M2 monomer synthesis polymer
modified NMs (NMs-(M1)m-(M2)n) (where m and n are the degrees of polymerization). In the second strategy, monomers are bonded on the surface of NMs as radical covalently. Chemical defect functionalization is the most suitable and more preferred method than sidewall functionalization. The use of NMs, which have oxygen-containing groups on their surface, is the most preferred strategy because of the great variety of reactions of oxygen groups [91
98]. Behbahani et al. fabricated polypropylene amine dendrimers (POPAM)
grafted MWCNT hybrid material as sorbent. The synthesis procedure consists of three stages: (1) oxidized MWCNTs (MWCNTs-COOH) were converted to MWCNTsCOCl in the SOCl2 and DMF medium by heating at 80 C for 50 h, (2) MWCNTsNH2 was produced by the reaction of MWCNTs-COCl with NaN3 at 100 C in DMF medium, and (3) the generation of first, second, and third POPAM on the amino-functionalized MWCNTs. The new material was used for SPE of Au(III) and Pd(II) traces from the aqueous phase prior to their AAS determinations [91]. Zhang et al. modified MWCNTs covalently with molecularly imprinted polymers (MIPs) by using acryloyl-β-cyclodextrin (acryloyl-β-CD) and methacrylic acid (MAA) as the binary functional monomers and erythromycin as the template. This synthesis procedure consisted of five successive steps: (1) formation of carboxyl group on the surface of MWCNTs (MWCNTs-COOH) by oxidizing with acids, (2) synthesis of MWCNTs-COCl in SOCl2 medium by reflux system at 60 C for 24 h,

388

Handbook of Nanomaterials in Analytical Chemistry

(3) synthesis of MWCNTs from MWCNTs-COCl in the presence of APTES and vinyltriethoxysilane, (4) production of acryloyl-β-cyclodextrins, and (5) reaction of MWCNTs particles with acryloyl-β-cyclodextrins in the presence of ethylene glycol dimethacrylate and α,α0 -azoisobutyronitrile [92]. The characterization studies for this new material were carried out by using techniques such as FT-IR spectroscopy, SEM, and transmission electron microscopy (TEM). SEM and TEM results showed that the average thickness of the MIP layer on the surface of MWCNTs was approximately 25 nm. The new sorbent was used for the separation and preconcentration of erythromycin from chicken muscle prior to its HPLC-UV detection. Tan et al. fabricated MIP-modified membrane-protected MWCNTs as a sorbent system for the separation and preconcentration of triazine at trace level in water and milk samples. In the microextraction application, MWCNTs-MIP prepared was set inside a polypropylene membrane envelope and then was clamped onto a paper clip. For extraction, the prepared membrane was first impregnated with toluene and later immersed in sample solutions. Analytes sorbed on the MWCNTs-MIP were desorbed and analyzed by LC analysis. In the fabrication of this new sorbent, MWCNTs-COOH particles were converted to MWCNTs-CH2 5 CH2 and then prometryn MWCNTs-MIPs were fabricated by the copolymerization of MAA and 3(trimethoxysilyl) propyl methacrylate in the presence of prometryn on the surface of MWCNTs-CH2 5 CH2 [93]. In a different application, Chen et al. modified MWCNTs with MIPs by using 4vinylpyridine and MAA as bifunctional monomers. As in previously described methods, pristine MWCNTs were converted to MWCNTs-COOH by oxidizing acids and then MWCNTs-COCl with thionyl chloride by reflux system at 80 C for 24 h. MWCNTs
CONHCH 5 CH2 was obtained by the reaction of MWCNTs-COCl with acrylamide [94]. In the last step, 200 mg of MWCNTs
CONHCH 5 CH2 was mixed in a solution including 0.1421 g of rhein, 0.1722 g of MAA, 0.2028 g of 4-VP, and DMF for 0.5 h, and then 1.982 g of ethylene glycol dimethacrylate, 30 mg of 2,2-azobisisobutyronitrile, and DMF were added into the first mixture, and the obtained second mixture was purged with nitrogen and left for polymerization at 60 C in a water bath. The prepared MWCNTs-MIP was used as a sorbent for SPE of trace amount of rhein (4,5-dihydroxyanthraquinone2-carboxylic acid). The concentration of rhein in eluent was analyzed with HPLC [94]. Kibechu et al. modified reduced GO with pyrene-imprinted polymer to obtain new GO-MIPs as an SPE material for the separation and preconcentration of PAHs in water samples. After extraction, analyses were carried out by GC
TOF/MS. The new GO-MIP sorbent was produced by a free-radical polymerization of 4vinylpyridine and MAA monomers and ethylene glycol dimethacrylate cross-linker. They analyzed PAHs in water samples with recoveries between 73% and 105.4%. The new sorbent was used at least five times, which performed successfully every time [95]. Sedghi et al. prepared GO@MIP composite by using the GO sheets as polymerization surface, acrylamide and β-cyclodextrin as functional monomers,

Functionalized nanomaterials for sample preparation methods

389

diphenylamine (DPA) as target molecule, N,N-methylene bisacrylamide as crosslinker, and azobisisobutyronitrile as initiator. The new composite was characterized by XRD, FT-IR, thermogravimetric analysis (TGA), SEM, and energy-dispersive spectroscopy (EDS) methods. Host
guest interactions between cyclodextrin-based polymer and diphenylamine by the inclusion complex through the interaction of DPA and β-CD lead to high extraction efficiency. The innovative GO@MIP sorbent provided highly improved imprinting effect, high adsorption capacity, and fast adsorption kinetic [96]. Cheng et al. fabricated a novel GO-MIPs for dispersive SPME of trace amount of bis(2-ethylhexyl) phthalate (DEHP) in environmental water samples prior to its HPLC-UV determination. They used precipitation-polymerization method. In this method, GO, MAA, ethylene dimethacrylate, and DEHP were used as supporting materials, functional monomer, cross-linker, and template molecules, respectively. The developed d-SPME method was applied to analyze DEHP in environmental water samples with good recoveries (82%
92%). EFs of over 100-fold with the LOD of 0.92 ng mL21 were obtained [97]. Liang et al. fabricated a monolithic column consisting carbon quantum dots-doped dummy MIP and used this column system for the extraction and preconcentration of aflatoxin B1 (AFB1) in peanut followed by its HPLC
fluorescence determination. The synthesis procedure was based on the in situ polymerization reaction in the presence of 5,7-dimethoxycoumarin as dummy template molecule. The in situ polymerization reaction was carried out in a water bath [98]. Good recovery results ranging from 79.5% to 91.2% with low intra- and interday RSDs (1.2% and 4.9%) were obtained for the extraction and analysis of AFB1 in peanut. LOD, limit of quantitation, and enhancement factor were found as 0.118, 0.393, and 71 ng mL21, respectively [98].

15.2.1.1.2 Noncovalent functionalization of carbon-based nanomaterials Although the functionalized adsorbents obtained by covalent modification of NPs with a complexing agent or organic group offer significant use advantages, the production of these materials is difficult. Hence, noncovalent modification of NPs with different functional groups, such as complexing agent-organic groups [TAR, poly (diallylmethylammoniumchloride) Aliquat 336, tartrazine, di-(2-ethylhexyl) phosphoric acid, tannic acid, tri-octyl phosphine oxide, 5-(4-dimethylamino-benzylidene)-rhodanine, etc.]; biomolecules (carbohydrates, proteins, enzymes, and DNA); polymers [polyaniline (PANI), polypyrrole, poly(3,4-dioxythiophene), polydiphenylamine, polyethyleneimine, polyvinylalcohol, poly(2-aminothiophenol), etc.]; surfactants; ionic liquids (ILs) (butylmethylimidazoliumhexafluorophosphate [BMIm] [PF6], hexylmethylimidazolium hexafluorophosphate [HMIm][PF6], etc.); and biological materials (bacteria, like biochar), is a good choice [99
102]. The executive forces in noncovalent modification are the hydrophobic, van der Waals, and/or electrostatic interactions classified as physical adsorption. These physical modification methods generally are simpler, effective, cheap, and ecofriendly than covalent modification methods to obtain desired extraction sorbents.

390

Handbook of Nanomaterials in Analytical Chemistry

When reviewing literature studies, it is observed that impregnation functionalization of NMs with complexing agent-organic groups is used frequently in the extraction of heavy metals and radioactive species since especially impregnation of complexing agents or organic compounds on the surface of NMs provide high selectivity and high adsorption capacity toward metal and radioactive species due to functional groups having O, S, N, etc. atoms [99
102]. ALOthman et al. impregnated MWCNTs with TAR to obtain selective sorbent toward Ni(II), Pb(II), Cd(II), and Zn(II) ions. In this modification procedure, 0.2 g of MWCNTs was added in 0.5% of TAR solution (25 mL), and the obtained mixture was stirred for 12 h. TAR-impregnated MWCNTs were filtered, washed, and dried prior to use. They filled the new sorbent in the glass column system for SPE of metal ions at trace level. The metal ions, which retained on the TARimpregnated MWCNTs at pH 7.0, were eluted with 3 mol L21 acetic acid and analyzed FAAS detection system. The developed SPE method was applied to analyze trace amounts of heavy metal ions in food samples [99]. Habila et al. fabricated 1-nitroso-2-naphthol-impregnated MWCNTs as SPE sorbent for the separation and preconcentration of lead(II) and copper(II) ions prior to their FAAS determinations. The developed SPE method was applied to different food and water samples [100]. Gouda et al. used MWCNT impregnated with 2-(2-benzothiazolylazo)orcinol (BTAO) as SPE sorbent for the extraction and preconcentration of trace levels of Zn(II) Cu(II), Pb(II), Ni(II), and Cd(II) ions. In general impregnation procedure, 200 mg of MWCNTs was mixed with 1.0 3 1023 mol L21 of BTAO solution for 12 h. The obtained sorbent was filled into 150 mm 3 10 mm glass column for the extraction of heavy metal ions. The metal ions at trace levels were sorbed on the MWCNTs-BTAO material at pH 7.0 and eluted with 5.0 mL of 2.0 mol L21 HNO3. The preconcentration factor was found as 100. The LODs were found in range of 0.7
2.2 μg L21 [101]. Soylak and Topal used MWCNTs impregnated with tartrazine for SPE of trace amounts of Cd(II) and Pb(II) ions, followed by their FAAS determination. The suggested SPE-FAAS procedure provided LODs of 6.6 and 0.8 mg L21, respectively, for Pb(II) and Cd(II) and preconcentration factor of 40 [102]. Noncovalent modification of NMs with polymers consists of two steps: (1) physical mixing of NMs in solution and (2) in situ polymerization of monomers in the presence of NMs or surfactant-assisted formation of polymers on the surface of NMs [103
110]. Sahmetlioglu et al. modified MWCNTs with polypyrrole and used the obtained composite material for SPE of Pb(II) ions in water samples. In the synthesis procedure an acidic mixture consists of 0.25 g of MWCNTs and 250 μL of pyrrole monomer was stirred for 30 min at 0 C in ice bath. Then, stoichiometric amount of acidic ammonium persulfate solution was added into the mixture drop by drop and stirred for 5 h. At this stage, black polypyrrole particles were formed on the surface of MWCNTs. The obtained polypyrrole
MWCNT composite was washed, dried, and filled into a glass column [103].

Functionalized nanomaterials for sample preparation methods

391

Chen et al. modified MWCNTs with branched cationic polyethyleneimine (BPEI) to obtain an inorganic
organic hybrid material. They converted MWCNTs into MWCNTs-COOH by oxidizing them in a sulfuric acid/nitric acid mixture (3:1, v/v). Modification of MWCNTs-COOH with BPEI was based on the electrostatic attraction between the carboxyl groups on the oxidized MWCNT surface and the positively charged protonated amines in the polymer. The prepared material was filled in a minicolumn for online SPE of As(V) at trace level at pH 5.8. The column system was combined to hydride generation atomic fluorescence spectrometry. The developed method was applied to water samples [104]. Nabid et al. used MWCNTs-poly(2-amino thiophenol) nanocomposites as sorbent for SPE of trace levels of Cd(II) and Pb(II) ions in some environmental samples. The N and S atoms in conducting polymer share electron pairs with metal ions, which lead to the adsorption of metal ions on the macromolecular chains. In the fabrication of poly(2-amino thiophenol) on the surface of MWCNTs, 0.5 g of MWCNTs and 1.15 mmol of 2-aminothiophenol were stirred at 5 C in ice bath. Then, stoichiometric amount of acidic ammonium persulfate solution was added into the mixture drop by drop and stirred for 5 h. At this stage, poly(2-amino thiophenol) was formed on the surface of MWCNTs. The obtained nanocomposites were washed and dried in a vacuum oven at 60 C for 24 h [105]. Zhang et al. used in situ electrochemical polymerization method to fabricate a novel sulfonated graphene/polypyrrole (SG/PPy) SPME coating on a stainless steel wire. The optimum parameters for sorbent fabrication process were SG doping amount of 1.5 mg mL21 and polymerization time of 15 min. The SG/PPy coating used at least 200 replicate extractions with excellent mechanical durability and thermal stability. Moreover, the new material showed higher extraction capacity and selectivity to volatile terpenes than commonly used commercial materials. SG/PPy coating was practically used to analyze the volatile compounds from fennel and star anise samples [106]. Han et al. prepared an SPME-coating material by using polysilicon fullerene. The new material was used for the extraction and preconcentration of aromatic compounds at trace level. The obtained results showed that the new polysilicon fullerene was more selective, sensitive, and efficient than nonpolar PDMS commercial availably. Further, the lifetime, reproducibility, and thermal stability of polysilicon fullerene coat are better than the PDMS commercial availably [107]. Zhang et al. prepared poly(3-methylthiophene carbazole)/GO composite on a stainless steel wire by using electrochemical synthesis procedure. The new device was utilized as headspace SPME device for the separation and preconcentration of dodecanol, nonanal, undecanol, decanal, and octanal. After extraction stage, the concentration of analytes was measured by GC. The SPME fiber was denoted as P (3MeT-Cz)/GO fiber and it has a coating thickness of about 55 μm [108]. Another possible application of electrochemical deposition method was searched by Behzadi et al. They prepared poly(o-anisidine)/GO nanosheets on a steel wire as headspace SPME device. The new device was used for the separation and preconcentration of trace levels of xylenes, toluene, benzene, and ethylbenzene prior to their GC detections [109].

392

Handbook of Nanomaterials in Analytical Chemistry

Kojidi et al. prepared poly(2,6-diaminopyridine)-modified GO composite materials by a simple in situ polymerization of 2,6-diaminopyridine monomer in a mixture of GO particles. In that synthesis method, 120 mg of GO was dispersed in a solution, including water and ethanol solution. Then, 1036 mg of 2,6-diaminopyridine was added into the mixture of GO and the polymerization started with the rapid addition of ammonium persulfate. The mixture was obtained at 0 C for 24 h. The obtained black precipitate was washed with different solutions, dried, and filled in a glass column for SPE of cadmium(II) traces. The new material was characterized by FT-IR, XRD, and SEM methods. The concentration of cadmium in last phases was measured by FAAS [110]. The introduction of new green extraction solvents, such as surfactants, ILs, deep eutectic solvents (DESs), switchable solvents, and bioderived solvents in the liquid phase
based analytical sample preparation methods was remarkable. These solvents were used as effective and selective extraction ones in thousands of liquid phase
based separation and preconcentration methods, such as liquid
liquid extraction, single drop microextraction, dispersive liquid
liquid microextraction, and solidified organic drop microextraction. Once the scientists realized that these solvents showed a high selectivity to different analytes, the idea of using these solvents in combination with solid-phase sorbents leads to new ideas and practices in the SPE/SPME fields [111
114]. For instance, the covalent or noncovalent modification of NMs with surfactants, ILs, DESs, and bioderived solvents leads to the enhancement of the extraction procedure and fulfills the principles of green analytical chemistry [112
115]. Perhaps the most important and desired benefits of their use as functionalizing agents in the modification of different nano-sized sorbents are low toxicity and biodegradability. Furthermore, they can be used as green extraction mediums for the separation and preconcentration of trace organic, inorganic, and bioactive species [111
119]. ILs are synthesized by combining asymmetric organic cations with different types of organic or inorganic anions. The common organic cations used are ammonium, pyridinium, pyrrolidinium, and imidazolium, whereas organic or inorganic anions are chloride, bromide, hexafluorophosphate, and tetrafluoroborate. As ILs provided low vapor pressure, wide viscosity range, and high thermal stability to users, those are preferred in sample preparation, chromatography, and electrochemistry applications instead of using toxic organic solvents. ILs show high affinity to some inorganic, organic, and bioactive species due to the presence of dipole
dipole, electrostatic interactions, and hydrogen bonding along with the alkyl groups of cations in them. Hence, the modification of NMs with ILs provided high adsorption capacity, improved selectivity, and high interactive characteristics toward analytes. NMs modified with ILs can be used in different sorptive-based extraction procedures (e.g., SPE, μSPE, SPME, d-SPE, and DμSPE) [111
119]. Combination uses of ILs with solid-phase sorbents were reported for the first time in 2005. In this study, SPME fiber was coated with disposable ILs before taking the extraction step. 1-Octyl-3-methylimidazolium hexafluorophosphate ([C8MIM][PF6]) IL was used for the modification of PDMS. The prepared fiber

Functionalized nanomaterials for sample preparation methods

393

was used for an SPME of headspace of benzene, ethylbenzene, xylenes, and toluene in paint samples [112]. Li et al. prepared a headspace SPME device that consists of MWCNTs-COOH, IL (i.e., 1-hydroxyethyl-3-methylimidazolium tetrafluoroborate), reduced graphene oxide (rGO), PANI, and stainless steel wires. The synthesis procedure includes two steps: (1) formation of 3D porous materials (MWCNTs-rGO-IL) by one-step selfassembly process and (2) coelectrodeposition of MWCNTs-rGO-IL with PANI on stainless steel wires by cyclic voltammetry. The new material was characterized and used for the headspace SPME of octanol, nonanol, geraniol, decanol, undecanol, and dodecanol prior to performing GC analysis [113]. Zhang et al. prepared a 3D IL-ferrite functionalized GO nanocomposite (3D-ILFe3O4-GO) as a sorbent in pipette-tip SPE (PT-SPE) of 16 PAHs in human blood samples. Analyses were carried out by GC
MS detections. When compared with conventional SPE applications, the PT-SPE method provided important applicable advantages, such as use of low volume of solvent (1.0 mL) and blood sample (0.2 mL) and usability for many times (at least 10 times). Analytes in the blood samples can be analyzed with the developed method between good recoveries (85.0%
115%). The LOQs were found in the range of 0.007
0.013 μg L21 [114]. In a different application, IL-functionalized graphene was fabricated for PT-SPE of auxins in soybean sprouts. In this procedure, thiolene click chemistry was used for the functional modification of pentafluorobenzyl imidazolium bromide IL with graphene. The modification of graphene with ILs leads to an aggregation prevention of graphene as well as improvements in the interaction between graphene and analytes by hydrogen bonding, π
π interactions, electrostatic interactions, and ionic exchange [115]. Hamidi et al. synthesized an IL-functionalized magnetic GO/polypyrrole composite for mixed hemimicelles dispersive micro-SPE of methotrexate from urine samples prior to its spectrophotometric determination [116]. 1-Hexadecyl-3methylimidazolium bromide (C16mimBr) was used as IL. The authors modeled interactions between methotrexate and sorbent by molecular docking, and the interaction energy was found as 28.35 kcal mol21 [116]. Zhang et al. fabricated a new 3D IL-functionalized magnetic GO nanocomposite (3D-IL@mGO), characterized by SEM, vibrating sample magnetometer, and XPS methods and applied for the magnetic d-SPE (MSPE) of 16 PAHs in vegetable oil followed by the GC
MS analysis [117]. The new material was synthesized in two steps: Step 1: the synthesis of IL@mGO was carried out by solvothermal reaction under N2 gas, 1.0 g NaOH, 2.5 g FeCl3  6H2O, and 7.5 g NaAc were mixed in 100 mL EG at 50 C until the transparent solution was obtained. Then 50 mg 1-(3aminopropyl)-3-methylimidazolium bromide and 50 mg of GO were combined and stirred vigorously at 80 C for 1 h prior to solvothermal reaction. The resulting IL@mGO was washed for several times and dried. Step 2: the synthesis of 3DIL@mGO was carried out by free-radical copolymerization; 100 mg of IL@mGO, 0.0143 mol of divinylbenzene, and 0.020 mol of maleic anhydride were dissolved in tetrahydrofuran under the inert gas. Then, 1.0 g of benzoyl peroxide was mixed with the obtained solution at 80 C and refluxed under inert atmosphere for 2 h.

394

Handbook of Nanomaterials in Analytical Chemistry

The obtained 3D-IL@mGO material was washed, dried, and used in the MSPE application. Wu et al. used IL-coated magnetic GO NPs as a mixed hemimicelles SPE material for cephalosporins in biological samples followed by HPLC analysis [118]. The synthesis procedure consisted of two main steps: the synthesis of GO from graphite by the modified Hummers method and the synthesis of magnetic GO NPs (Fe3O4/ GO NPs) by solvothermal reaction. In general, DESs are prepared by mixing two or more components to obtain a new liquid, which has a lower melting point than each individual component. The main driving force in the formation of these solvents is the hydrogen bond between the constituent components. DESs were discovered by Abbot et al. in 2003 when they searched the solvent features of the eutectic mixtures of different types of ammonium salts and urea [119,120]. Although many DES can be produced by self-association of hydrogen bond donors (HBDs) and acceptors, the most preferred DESs are prepared by the combination of choline chloride (ChCl) with carboxylic acids (e.g., citric, succinic, and oxalic acids), urea, and glycerol as HBDs. Furthermore, DESs can be prepared by natural, available, and cheap components, such as alcohols, sugars, amino acids, and organic acids. These DESs are called natural deep eutectic solvents (NADESs). In general, DESs and NADESs have been used as extraction solvents in the liquid phase
based extraction methods due to their green properties, adjustable viscosity, and high selectivity characteristics toward analytes. At the same time, the preparation and use of SPE systems in desired properties as a result of modification of different sorbents with DESs and NADESs have attracted considerable attention of scientists [119
122]. Liu et al. modified graphene with a DES, which was prepared from choline chloride and ethylene glycol. In the modification procedure, 200 mg of GO was added in the solution, including 200 mL of water, 140 mg of ChCl, and 120 mg of EG, and the obtained mixture was stirred and refluxed at 80 C for 12 h. In the last step, 2 g of hydrazine hydrate was added, and this mixture was stirred at 80 for 24 h. The new sorbent was used for the PT-SPE of sulfamerazine traces prior to performing HPLC analysis. Sulfamerazine in water samples was extracted and analyzed with low LOD (10 mg L21) and high extraction efficiencies (91.01%
96.82%) [120]. Different applications of DES with sorbents were reported by Wang et al. in 2016. They fabricated GO-DES@silica by using DESs and GO-IL@silica by using ILs. In the synthesis procedure, GO was modified by DESs or ILs to obtain GODES and GO-IL, and then the prepared materials were connected to surface of silica by a covalent bonding between COOH groups of GO and amino group of silica. Subsequent reactions of these materials with hydrazine solution lead to the formation of G-DES@silica and G-IL@silica materials. The obtained final products (GDES@silica and G-IL@silica) were used for the separation and preconcentration of CPs in water samples prior to HPLC-UV determinations. The results showed that GDES1@silica (ChCl:formic acid, 1:2), GO-DES4@silica (ChCl:urea, 1:2),

Functionalized nanomaterials for sample preparation methods

395

G-IL3@silica ([HMIM][Tf2N]), and GO-IL4@silica ([EMIM][Br]) have a better extraction performance than that of other sorbents for the extraction of CPs [121]. Yousefi et al. produced DES magnetic bucky gels by modifying magnetic MWCNTs with DES (choline chloride/urea). Modification of magnetic MWCNTs with DES was based on the noncovalent interactions. The new DES magnetic bucky gels were used as sorbents in d-SPE of OCPs in water samples with EFs between 270 and 340 [122]. Functionalization of NMs with living or died bacteria, such as Escherichia coli, Pseudomonas aeruginosa, Geobacillus toebii, Geobacillus thermoleovorans, Bacillus sp., Pleurotus eryngii, and Bacillus altitudinis, plays an important role in the sample preparation methods. These sorption-based methods are called “biosorption” in the literature [123
125]. Aydemir et al. modified MWCNTs with died E. coli bacteria to prepare a biosorbent for the SPE cobalt, copper, nickel, and cadmium at trace level followed by FAAS analysis. In order to immobilize nonliving E. coli on the MWCNTs, the same amount of nonliving E. coli and MWCNTs was mixed together in water at 200 rpm for 2 h. After immobilization, E. coli
MWCNTs was separated from aqueous phase, dried, stabilized in a vacuum oven at about 80 C
105 C for 24 h and ground. The new sorbent has high adsorption affinity metal ions at a pH value of 7. The retained ions on the E. coli
MWCNTs were eluted by using 0.5 M nitric acid [123]. Tuzen et al. prepared P. aeruginosa immobilized MWCNTs as biosorbent for the separation and preconcentration of nickel(II), cadmium(II), lead(II), chromium (III), manganese(II), and cobalt(II) ions at trace levels. They used mixing technique, on the basis of the physical immobilization, to obtain biosorbent [124]. Ozdemir et al. prepared B. altitudinis
immobilized ND as SPE sorbent for the separation and preconcentration of Pb21, Co21, Cr61, and Hg21 ions. In the preparation method of B. altitudinis
immobilized ND, 3 mL distilled water and 300 mg of dried and autoclaved B. altitudinis were shaken in a 250 mL glass bottle for 8 h, then, 300 mg of ND was added into the bacteria mixture and thoroughly mixed. The obtained biosorbent was filled into a column for SPE applications. After extraction, concentrations of analytes in eluent were measured by ICP-OES [125].

15.2.2 Metallic and metal-oxide nanomaterials Metallic and metal-oxide NPs belong to inorganic-based NM class formed by combining one, two, or three metals and/or their oxides. Metal and metal-oxide NPs are frequently used in sample preparation methods, chromatographic separation methods, spectroscopic analysis techniques, and sensor technologies due to their availability by simple and cheap preparations, their easy modification abilities with organic and inorganic-based materials, their effective mechanical, chemical, electrical, and catalytic properties, having a large surface area and high adsorption capacities. As the most used metallic NPs in analytical applications are Ag, Au, Pd, Pt, Cu, Ni, Fe, Co, and Mn, the usually preferred metallic NPs are Fe3O4, Al2O3, TiO2, MnO, ZrO2, CeO2, and ZnO [126
130].

396

Handbook of Nanomaterials in Analytical Chemistry

The first stage of immobilization of preproduced metal NPs (MNPs) and metaloxide NPs is the chemical modification of the substrate surfaces. The second stage is the immobilization of preproduced MNPs and metal-oxide NPs by electrostatic interactions or weaker physical interactions with unmodified surfaces. Many methods have been introduced to directly fabricate MNPs and metal-oxide NPs on surfaces in one step [e.g., hydrothermal growth, potentiostatic anodization, electroless and electrochemical deposition, liquid-phase deposition (LPD), and in situ chemical oxidation] [131
134].

15.2.2.1 Functionalization of the metallic and metal-oxide nanomaterials 15.2.2.1.1 Chemical functionalization of the surface of the metallic and metaloxide nanomaterials Immobilization of MNPs and metal-oxide NPs on a substrate is started with the chemical modification of the substrate by three different processes: (1) silanization, (2) sol
gel, and (3) usage of bifunctional compounds. 15.2.2.1.1.1 Silanization The modification of surfaces of materials with thiolterminated and amine-terminated silane groups is one of the most used procedures for immobilizing MNPs and metal-oxide NPs. In the silanization reactions, a surface is covered by silanol groups and then hydrolysis of alkoxy groups with the liberation of silanol groups and the release of alcohols, and producing siloxane linkages on the surface by the release of water molecules, which leads to the formation of covalent bonds between the surface and silanol groups [126]. Silane groups, such as 3-methacryloxypropyltrimethoxysilane APTES, (3-chloropropyl)-trimethoxysilane, TMSPDETA, and TMSPEDA, are frequently used as coupling agents for covalent modification of NMs. Required MNPs and metaloxide NPs are covalently attached to NMs via these silane groups. 15.2.2.1.1.2 Sol
gel method The sol
gel method is considered effective to modify the surface of substrates. Obtaining of a high surface area and stable surfaces is the most important advantage of the sol
gel method. The chemical and physical properties of the materials obtained by the sol
gel method are related to the experimental conditions applied. The sol
gel method involves two main reactions: (1) hydrolysis of the precursor in the acidic or basic mediums and (2) polycondensation of the hydrolyzed products. In this way a polymeric network is formed in which MNPs can be retained [126]. 15.2.2.1.1.3 Bifunctional compounds Bifunctional compounds are molecular linker agents and frequently used for the immobilization of MNPs on a surface. The natures of both the MNP and the solid substrate are important to accomplish effective chemical modification by using bifunctional compounds. For example, MNPs can be immobilized on a surface, and thiol functionalization with alkanedithiols is applied to immobilize MNPs on inorganic and organic substrates [135].

Functionalized nanomaterials for sample preparation methods

397

15.2.2.1.2 Functionalization of the surface of the metallic and metal-oxide nanomaterials via interactions Immobilization of MNPs with electrostatic interactions is based on the attractive electrostatic interactions of charged surfaces with opposite-charged MNPs, and these methods play an important role in the analytical applications [127
130]. As an example application, polymeric monoliths functionalized with quaternary ammonium groups are the good substrates for the attachment of the citrate-capped iron-oxide NPs [127]. In these methods, high molecular weight polycations and polyanions are used as electrostatic interaction agents between surface and MNPs. This immobilization method is generally called “layer-by-layer deposition,” while poly(allylamine hydrochloride), as polycation, is commonly used for the immobilization of negative-charged MNPs, such as citrate-capped gold nanospheres [128], citrate-stabilized AgNPs [129], and poly(styrene sulfonate) as polyanion is usually used for immobilization of positive-charged MNPs, such as cetyl trimethylammonium bromide-capped gold nanorods [130]. Weaker physical interactions, such as van der Waals forces, can become executive force to immobilize MNPs and metal-oxide NPs on different substrates utilized for analytical applications. For example, metal-oxide NPs can be immobilized on the carbon-based electrodes by immersing the substrate in the colloidal solution of MNPs for a certain time [131]. Although physical interaction-based immobilization methods are frequently used, the stability and the durability of the obtained materials are important because of the weak interactions between MNPs and metal-oxide NPs and the solid substrate.

15.2.2.1.3 Functionalization of the surface of the metallic and metal-oxide nanomaterials via in situ chemical oxidation In situ chemical oxidation of metallic substrates is used to obtain nanostructured surfaces for different analytical applications. When compared with other immobilization procedures, this method provides high stability and durability. In an example application, TiO2 NPs can be obtained on the surface of metals by the oxidization of Ti wires at ,100 C with hydrogen peroxide [132].

15.2.2.1.4 Functionalization of the surface of the metallic and metal-oxide nanomaterials via solvothermal synthesis The solvothermal synthesis method can be explained as follows: reaction of components in water or a in different solution medium at high temperature and high pressure. When reactions are carried out in water, the method is called “hydrothermal.” Most of the MNPs and metal-oxide NPs, such as Ag, Au, Pd, Pt, ZnO, Fe3O4, MnO, CuO, Mn3O4, and NiCo2O4, can be produced simply by the solvothermal synthesis method [126,133,134].

15.2.2.1.5 Functionalization of the surface of the metallic and metal-oxide nanomaterials via liquid-phase deposition LPD can be used for the fabrication of a thin layer of metal-oxide NP films, such as TiO2, ZnO, ZrO2, Cr2O3, CoO, In2O3, MnO, NiO, and CuO. Mainly the LPD

398

Handbook of Nanomaterials in Analytical Chemistry

method is based on the hydrolysis reaction of metal-fluoro complex ions and then the precipitation of metal-oxide NPs by an addition of H3BO3 or metallic Al [136
138].

15.2.2.1.6 Functionalization of the surface of the metallic and metal-oxide nanomaterials via electroless and electrochemical deposition Reductions of metal ions to MNPs by using a reducing agent (electroless) or by applying an external current (electrochemical deposition) are another simple way to form MNPs at the surface of a substrate. In the electrochemical deposition method, substrates behave as cathodes, and the reduction of metal ions is carried out on the surface of the substrate. Both electrochemical deposition and electroless methods are binder-free immobilization techniques, because any linker agent is not used. The desired chemical composition, the size, and the composition of MNPs can be provided by changing experimental conditions [139
141].

15.2.2.1.7 Functionalization of the surface of the metallic and metal-oxide nanomaterials via potentiostatic anodization Potentiostatic anodization is another method to fabricate metal-oxide NPs on solid substrates. In this system, metallic substrates behave as electrode for the growth of metal-oxide NPs on them. In this system an anodic voltage was applied to the metals in the fluoride-containing nonaqueous electrolyte medium to obtain metaloxide NPs or surface-oxide films. An example of synthesis is explained on the formation of TiO2 nanotubes on a Ti substrate [126]. The obtaining of pores on the metallic surface is the first stage of synthesis, which is performed for the formation of a water-soluble hexafluorotitanate(IV) complex [TiF6]22. In the second stage, [TiF6]22 is converted to Ti(OH)4 by instantaneous hydrolysis reaction in the pores of metals. In the final step, electrochemical anodization is applied for the formation of metal-oxide NPs at the surface of the metallic substrate. These methods can also be applicable for the fabrication of different valve metals, such as zirconium, tantalum, hafnium, niobium, and tungsten [126]. For analytical applications, including detection and sample preparation, MNPs and metal-oxide NPs can be modified with different materials, such as carbonbased NMs (SWCNTs, DWCNTs, MWCNTs, fullerenes, nanodimonds, graphene, GO, and C-nanofiber), polymers, silicon-based substrates, and metallic surfaces. A considerable number of metal, metal-oxide NPs, and their functionalized forms are frequently preferred for sample preparation methods, such as SPE, SPME, and liquid-phase microextraction due to their simple functionalization capabilities with different materials (polymers, carbon-based NMs, nanofibers, and so on), high surface areas, high adsorption capacities, and high chemical and mechanical stability [142
146]. Jiang et al. synthesized gold NP-modified reduced GO as a sorbent for SPE of ochratoxin A, AFB1, aflatoxin M1, zearalanone, zearalenone, α-zearalanol, β-zearalanol, α-zearalenol, and β-zearalenol in a milk sample prior to their ultrahigh performance liquid chromatography (UHPLC)
MS/MS analysis. Au NPs were obtained by a chemical reduction of Au31 ions in the presence of ascorbic

Functionalized nanomaterials for sample preparation methods

399

acid and sodium citrate. The developed SPE-UHPLC
MS/MS procedure allows the LOQ between 0.02 and 0.18 ng mL21, acceptable recoveries between 70.2 and 111.2 with RSD, in the range of 2.0%
14.9% [142]. Trujillo-Rodrı´guez and Anderson modified SPME fibers with silver-based polymeric IL sorbents to obtain a new SPME device. In the first step of synthesis procedure, IL monomers were formed by cations, including the Ag1 coordinated with two 1-vinylimidazole ligands. In the second step, polymeric IL sorbents were obtained on the commercial fibers by free-radical polymerization in the presence of either silver bis[(trifluoromethyl)sulfonyl]imide and/or a dicationic IL cross-linker. They prepared seven different types of SPME devices by using different combinations of ILs, cross-linkers, and their different mole ratios. The new SPME devices were used to separate and preconcentrate unsaturated compounds prior to performing the GC
FID analysis [143]. Yazdi et al. fabricated polypyrrole-silver nanocomposite for the separation and preconcentration of trace amounts of parabens in water and beverage samples by hollow fiber SPME. After performing the extraction step, analyses were carried out by HPLC-UV. First, polypropylene hollow fibers were modified with polypyrrole by a polymerization reaction in the presence of FeCl3. The prepared polypyrrolemodified hollow fibers were immersed in a solution of AgNPs, which was prepared by the modified Tollens procedure. LOD, LOQ, and linear range values for analytes were 0.01, 0.05, and 0.05
200 μg L21, respectively [144]. Yang et al. coated SPME fibers with nanoscale graphitic carbon nitride/copper oxide hybrid material (nano-g-C3N4/CuO) for the separation and preconcentration of pyrene, naphthalene, acenaphthene, anthracene, phenanthrene, and fluorene PAHs, followed by their GC analysis. The prepared new SPME device provided a better adsorption performance than each of the pristine nanoscale graphitic carbon nitride (nano-g-C3N4) or copper oxide (CuO). LODs lying in the range of 0.025
0.40 ng mL21, RSDs from 2.5% to 7.3%, lying in the linear range from 0.1 to 1000 ng mL21, were obtained with this new extraction system [145]. Ghani et al. constructed highly porous copper foam fibers on the surface of an unbreakable copper wire to obtain a new sorbent for the extraction and preconcentration of trace levels of xylene, toluene, benzene, and ethylbenzene in waters prior to their GC
FID analysis. A simple and rapid electrochemical method was used to fabricate the highly porous copper foam on the surface of copper wire. Under optimum conditions, LODs in the range of 0.12
0.41 μg L21, RSDs from 6.9% to 9.6%, in the linear range from 1 to 500 μg L21, and recoveries more than 88% were obtained by using this new extraction and analysis combination [146]. Yazdi et al. used MWCNT-zirconium oxide nanocomposite materials (MWCNTs-ZrO2) as coating materials for hollow fiber SPME of polyaromatic hydrocarbons before HPLC-UV determinations. Modification of polypropylene hollow fibers included the following steps: (1) conversion of Zr(OH)4 to ZrO2 NPs on the MWCNTs via a heating process to obtain MWCNTs-ZrO2 nanocomposite and (2) modification of polypropylene hollow fibers with the as-prepared MWCNTsZrO2 nanocomposite by sonication method [147].

400

Handbook of Nanomaterials in Analytical Chemistry

15.2.3 Magnetic nanomaterials In the last two decades, magnetic SPE methods using magnetic adsorbents have become one of the most commonly used methods for the separation and enrichment of organic, inorganic, and bioactive species at the matrix level. In 1973 Robinson ˇ r´ıkova´ and Safaˇ ˇ r´ık used et al. suggested the first magnetic separation [148]. But Safaˇ magnetic SPE term as an analytical application in 1999 [149]. They prepared a magnetic charcoal sorbent for magnetic SPE of safranin O and crystal violet in water samples [149]. About 460-fold preconcentration factor was obtained for analytes. The MSPE method is based on the adsorption and desorption of analytes on magnetic adsorbents that are added to the sample solution containing the analytes. In this method, different types of polymers, NMs, metals, and metal oxides that can be used as adsorbents are modified by magnetic particles, such as nano-sized Fe3O4, γ-Fe2O3, ZnFe2O4, and ZnFe2O4. In this way, adsorbents that do not show magnetic properties are given magnetic properties [150,151]. Magnetic NPs, such as Fe3O4 and γ-Fe2O3, have low stability in a solution medium, especially under acidic conditions, which cause the decomposition of materials in a short time and loss of their magnetic properties. To prevent this drawback, the materials obtained are modified by silica, alumina oxides, or different groups that are resistant to harsh working conditions [29,152]. The selection of the suitable sorbent-used MSPE is the most important step to be taken in this method, which affects the extraction efficiency as in other methods. Some of the most used new-generation SPME sorbents in MSPE applications are as follows [153
159]: 1. carbon NPs (CNTs, fullerenes, ND, graphene, GO, carbon dots, and modified carbon NPs); 2. metal oxides (SiO2, Al2O3, TiO2, etc.); 3. polymers (cyclodextrine, polypyrrole, polyaniline, gelatin, chitosan, polydivinylbenzeneco-methacrylic acid, etc.); 4. metal
organic frameworks; 5. MIPs; 6. mesoporous and nanoporous silicates; and 7. graphene-like materials (MoS2, MoSe2, WS2, C3N4, etc.).

The SPME is used to separate and preconcentrate a wide range of trace analytes in different matrix mediums, including the following [159
163]: 1. food, drug, and biological sample analysis; extraction and preconcentration of metals, dyes, pesticides, pharmaceutical active ingredients, etc.; 2. biomedicine; isolation, extraction, and preconcentration of different bioactive species, such as DNA, RNA, enzymes, proteins, peptides, and cells; 3. environmental analysis; extraction and preconcentration of metals, dyes, pesticides, pharmaceutical active ingredients, surfactants, PAHs, mutagenic, and carcinogenic analytes in water and sewage samples; and 4. earth and mineral science; extraction and preconcentration of valuable metals and radioactive species.

Functionalized nanomaterials for sample preparation methods

401

Some MSPE applications in the literature for the separation and preconcentration of trace organic and inorganic analytes are summarized in the following. ˇ r´ıkova´ and Safaˇ ˇ r´ık tested the applicability of magnetic SPE proceIn 2002 Safaˇ dure for high volumes of urine samples. For this purpose, they fabricated a reactive copper phthalocyanine dye immobilized magnetite particles for the separation and preconcentration of crystal violet dye as a model analyte in high volumes of urine samples as crystal violet leads to an increased risk of cancer for living cells [164]. In 2005 the same research group used the MSPE method to separate and preconcentrate nonionic surfactants based on aliphatic alcohols, hydrogenated fatty acid methyl esters, and oxyethylated nonylphenol in water samples [165]. Huang and Hu fabricated, characterized, and used γ-mercaptopropyltrimethoxysilane-modified silica-coated magnetic NPs (SCMNPs) as an innovative SPME sorbent for the separation and preconcentration of Pb, Hg, Cu, and Cd at trace levels in environmental and biological samples. In this method, 50 mg of magnetic sorbent was added in the sample solution, including metal ions (pH 6.0), and the obtained mixture was ultrasonicated for 10 min to ensure the adsorption of analytes on the magnetic sorbent. Then the sorbent was isolated from the sample solution phase by applying external magnetic field, and analytes on the sorbent were eluted with 1.0 mol L21 HCl and 2% (m/v) thiourea elution solution by using ultrasonication power. Analyte concentrations in the eluent phase were measured by ICP-MS. The LODs for analytes were between 24 and 56 pg L21 [166]. Suleiman et al. used bismuthiol-II-immobilized SCMNPs for the separation and preconcentration of trace amounts of Pb, Cu, and Cr in lake and river water samples. Analytes in the aqueous phase were extracted to 100 mg of magnetic nanosorbent phase at pH 7.0 by using an ultrasonic irritation source. A 1.0 mol L21 HNO3 solution was used to desorb analytes from the sorbent. Concentrations of analytes were measured by ICP-OES [167]. An important application of the magnetic sorbents (as on-chip online SPE) was reported by Li et al. in 2009. The authors fabricated a PDMS/glass hybrid microchip for online SPE and electrophoresis separation of the trace amount of fluorescence isothiocyanate-labeled phenylalanine. The extraction phase was prepared by the modification of the magnetic microspheres with hydroxyl-terminated PDMS (PDMS-OH). The extraction phase conveniently immobilized into the SPE channel by magnetic field. In this system, injection of the sample solution into the SPE channel (PDMS-OH microspheres bed) and desorption of analyte from the sorbent phase into the electrophoresis channel were electrically driven [168]. Cheng et al. used 1-hexadecyl-3methylimidazolium bromide (C16mimBr)-coated Fe3O4 magnetic NPs as an magnetic adsorbent for the mixed hemimicelles SPE of trace amounts of 2,4-dichlorophenol and 2,4,6-trichlorophenol compounds in environmental waters followed by HPLC-UV analysis. The new nano-sized sorbent provided a high surface area that leads to high adsorption capacity and high extraction efficiencies (74%
90%) at a minimum level of sorbent (40 mg) [169]. Jiang et al. used zincon-immobilized silica-coated magnetic Fe3O4 NPs for the magnetic SPE of trace amounts of lead in water samples prior to the determination by using a graphite furnace atomic absorption spectrometer. The detection limit

402

Handbook of Nanomaterials in Analytical Chemistry

(LOD), EF, and recovery results of the proposed method were found as 10 ng L21, 200, and 84%
104%, respectively [170]. Cui et al. prepared chitosan-modified magnetic NPs by an emulsion method for the magnetic separation and preconcentration of Cr(III) and Cr(VI) in lake and tap water samples prior to ICP-OES detection. The LOD, PF, and RSD% for Cr(III) and Cr(total) were found as 100, 0.02, and 0.03 ng mL21 and 4.8% and 5.6%, respectively [171]. Wang et al. used a hydrothermal reaction procedure to synthesize a Fe3O4-functionalized metal
organic framework (m-MOF) composite as an MSPE sorbent. They synthesized the metal
organic framework from Zn(II) and 2aminoterephthalic acid. X-ray diffraction, FT-IR, TGA, SEM, and magnetization methods were used for the characterization of m-MOF composites. The new magnetic sorbent was used for the separation and preconcentration of trace amounts of copper followed by ETAAS detection [172]. Azodi-Deilami used magnetic MIP (m-MIP) NPs as a magnetic SPE sorbent for tracing the amount of paracetamol in human blood plasma samples. In the synthesis of the m-MIPs, magnetite (Fe3O4) as the magnetic component, 2-(methacrylamido) ethyl methacrylate as a cross-linker, and MAA as a functional monomer were used. The m-MIPs synthesized were characterized by TEM, FT-IR, XRD, and vibrating sample magnetometry methods. Analysis of paracetamol in the last phase was measured by HPLC. The LOD, LOQ, PF, and RSD% recoveries for paracetamol were 0.17 μg L21, 0.4 μg L21, 40, and 4.5%, respectively [173].

15.3

Conclusion

From the detailed studies mentioned earlier, it is obvious that nanotechnology is a field that has been constantly renewed and developed rapidly. One of the most important scientific disciplines that have benefited from the unique opportunities and advantages offered by nanotechnology is undoubtedly the analytical chemistry, and it is obvious that this trend will rapidly increase day by day. The combination of dimensions, unique structures, and surface morphologies make NPs effective and interesting materials for sample preparation methods. Moreover, the functionalization capability of NMs by different agents and methods is one of the most important properties, which are used as per their desired capabilities, such as selectivity toward analyte or analytes, high adsorption capacity, solubility, physical, and chemical resistivity. Hence, the simple functionalization capability of NMs expands their applications in the field of sample preparation methods.

References [1] K.E. Geckeler, H. Nishide (Eds.), Advanced Nanomaterials, John Wiley & Sons, 2009. [2] C. Lutz, J.A. Steevens (Eds.), Nanomaterials: Risks and Benefits, Springer Science & Business Media, 2008.

Functionalized nanomaterials for sample preparation methods

403

[3] C.N.R. Rao, A. Mu¨ller, A.K. Cheetham (Eds.), The Chemistry of Nanomaterials: Synthesis, Properties and Applications, John Wiley & Sons, 2006. [4] K.T. Ramesh, Nanomaterials, Nanomaterials, Springer, Boston, MA, 2009, pp. 1
20. [5] H. Hosono, Y. Mishima, H. Takezoe, K.J. MacKenzie (Eds.), Nanomaterials: Research Towards Applications, vol. 161, Elsevier, 2006. [6] C.N.R. Rao, A. Mu¨ller, A.K. Cheetham (Eds.), Nanomaterials Chemistry: Recent Developments and New Directions, John Wiley & Sons, 2007. [7] A. Tiwari, A. Tiwari (Eds.), Bioengineered Nanomaterials, CRC Press, 2013. [8] M.S. Johal, Understanding Nanomaterials., CRC Press, 2012. [9] M.R. Mozafari (Ed.), Nanomaterials and Nanosystems for Biomedical Applications, Springer Science & Business Media, 2007. [10] G.A. Ozin, A. Arsenault, Nanochemistry: A Chemical Approach to Nanomaterials, Royal Society of Chemistry, 2015. [11] G.E. Fryxell, G. Cao (Eds.), Environmental Applications of Nanomaterials: Synthesis, Sorbents and Sensors, World Scientific, 2012. [12] X. Wang, Y. Guo, L. Yang, M. Han, J. Zhao, X. Cheng, Nanomaterials as sorbents to remove heavy metal ions in wastewater treatment, J. Environ. Anal. Toxicol. 2 (7) (2012) 154. [13] M. Ahmadi, H. Elmongy, T. Madrakian, M. Abdel-Rehim, Nanomaterials as sorbents for sample preparation in bioanalysis: a review, Anal. Chim. Acta 958 (2017) 1
21. [14] G. Yuan, Natural and modified nanomaterials as sorbents of environmental contaminants, J. Environ. Sci. Health, A 39 (10) (2004) 2661
2670. [15] A. Mehdinia, M.O. Aziz-Zanjani, Recent advances in nanomaterials utilized in fiber coatings for solid-phase microextraction, TrAC, Trends Anal. Chem. 42 (2013) 205
215. [16] K. Pyrzynska, Use of nanomaterials in sample preparation, TrAC, Trends Anal. Chem. 43 (2013) 100
108. [17] J.C. Vinci, L.A. Colon, Fractionation of carbon-based nanomaterials by anion-exchange HPLC, Anal. Chem. 84 (2) (2011) 1178
1183. [18] G. Aragay, F. Pino, A. Merkoci, Nanomaterials for sensing and destroying pesticides, Chem. Rev. 112 (10) (2012) 5317
5338. [19] M. Zhang, H. Qiu, Progress in stationary phases modified with carbonaceous nanomaterials for high-performance liquid chromatography, TrAC, Trends Anal. Chem. 65 (2015) 107
121. [20] G.B. Braun, S.J. Lee, T. Laurence, N. Fera, L. Fabris, G.C. Bazan, et al., Generalized approach to SERS-active nanomaterials via controlled nanoparticle linking, polymer encapsulation, and small-molecule infusion, J. Phys. Chem. C 113 (31) (2009) 13622
13629. [21] M.F. Cardinal, E. Vander Ende, R.A. Hackler, M.O. McAnally, P.C. Stair, G.C. Schatz, et al., Expanding applications of SERS through versatile nanomaterials engineering, Chem. Soc. Rev. 46 (13) (2017) 3886
3903. [22] C. Buzea, I.I. Pacheco, K. Robbie, Nanomaterials and nanoparticles: sources and toxicity, Biointerphases 2 (4) (2007) MR17
MR71. [23] A. Speltini, D. Merli, A. Profumo, Analytical application of carbon nanotubes, fullerenes and nanodiamonds in nanomaterials-based chromatographic stationary phases: a review, Anal. Chim. Acta 783 (2013) 1
16. [24] F. Valentini, G. Palleschi, Nanomaterials and analytical chemistry, Anal. Lett. 41 (4) (2008) 479
520.

404

Handbook of Nanomaterials in Analytical Chemistry

[25] Y. Su, Y. Xie, X. Hou, Y. Lv, Recent advances in analytical applications of nanomaterials in liquid-phase chemiluminescence, Appl. Spectrosc. Rev. 49 (3) (2014) 201
232. [26] S. Tong, S. Liu, H. Wang, Q. Jia, Recent advances of polymer monolithic columns functionalized with micro/nanomaterials: synthesis and application, Chromatographia 77 (1
2) (2014) 5
14. [27] J. Wang, S. Zheng, Y. Shao, J. Liu, Z. Xu, D. Zhu, Amino-functionalized Fe3O4@SiO2 core
shell magnetic nanomaterial as a novel adsorbent for aqueous heavy metals removal, J. Colloid Interface Sci. 349 (1) (2010) 293
299. [28] D. Huang, C. Deng, X. Zhang, Functionalized magnetic nanomaterials as solid-phase extraction adsorbents for organic pollutants in environmental analysis, Anal. Methods 6 (18) (2014) 7130
7141. [29] A.H. Lu, E.E. Salabas, F. Schu¨th, Magnetic nanoparticles: synthesis, protection, functionalization, and application, Angew. Chem. Int. Ed. 46 (8) (2007) 1222
1244. [30] C. Pereira, A.M. Pereira, C. Fernandes, M. Rocha, R. Mendes, M.P. Ferna´ndez-Garcı´a, et al., Superparamagnetic MFe2O4 (M 5 Fe, Co, Mn) nanoparticles: tuning the particle size and magnetic properties through a novel one-step coprecipitation route, Chem. Mater. 24 (8) (2012) 1496
1504. [31] V. Kruefu, A. Wisitsoraat, A. Tuantranont, S. Phanichphant, Ultra-sensitive H2S sensors based on hydrothermal/impregnation-made Ru-functionalized WO3 nanorods, Sens. Actuators, B: Chem. 215 (2015) 630
636. [32] D. Jagadeesan, M. Eswaramoorthy, Functionalized carbon nanomaterials derived from carbohydrates, Chem. Asian J. 5 (2) (2010) 232
243. [33] D. Li, J.T. McCann, Y. Xia, Use of electrospinning to directly fabricate hollow nanofibers with functionalized inner and outer surfaces, Small 1 (1) (2005) 83
86. [34] C.R. Crick, J.C. Bear, A. Kafizas, I.P. Parkin, Superhydrophobic photocatalytic surfaces through direct incorporation of titania nanoparticles into a polymer matrix by aerosol assisted chemical vapor deposition, Adv. Mater. 24 (26) (2012) 3505
3508. [35] B.G. Trewyn, I.I. Slowing, S. Giri, H.T. Chen, V.S.Y. Lin, Synthesis and functionalization of a mesoporous silica nanoparticle based on the sol
gel process and applications in controlled release, Acc. Chem. Res. 40 (9) (2007) 846
853. [36] S. Mohanty, S.K. Nayak, B.S. Kaith, S. Kalia (Eds.), Polymer Nanocomposites Based on Inorganic and Organic Nanomaterials, John Wiley & Sons, 2015. [37] V. Amendola, P. Riello, M. Meneghetti, Magnetic nanoparticles of iron carbide, iron oxide, iron@iron oxide, and metal iron synthesized by laser ablation in organic solvents, J. Phys. Chem. C 115 (12) (2010) 5140
5146. [38] X. Wang, L.H. Liu, O. Ramstroem, M. Yan, Engineering nanomaterial surfaces for biomedical applications, Exp. Biol. Med. 234 (10) (2009) 1128
1139. [39] M.R. Awual, M.M. Hasan, G.E. Eldesoky, M.A. Khaleque, M.M. Rahman, M. Naushad, Facile mercury detection and removal from aqueous media involving ligand impregnated conjugate nanomaterials, Chem. Eng. J. 290 (2016) 243
251. [40] W. Cai, L. Tan, J. Yu, M. Jaroniec, X. Liu, B. Cheng, et al., Synthesis of aminofunctionalized mesoporous alumina with enhanced affinity towards Cr(VI) and CO2, Chem. Eng. J. 239 (2014) 207
215. [41] L.I. Lulu, Y.A.O. Lu, D.U.A.N. Li, Application of Lithium-Selenium Batteries Using Covalent Organic Framework Composite Cathodes, Acta Physico-Chimica Sinica 35 (7) (2018) 734
739. [42] F.L. De La Puente, J.F. Nierengarten (Eds.), Fullerenes: Principles and Applications, Royal Society of Chemistry, 2011.

Functionalized nanomaterials for sample preparation methods

405

[43] J. Munoz, M. Gallego, M. Valca´rcel, Solid-phase extraction
gas chromatography
mass spectrometry using a fullerene sorbent for the determination of inorganic mercury(II), methylmercury(I) and ethylmercury(I) in surface waters at sub-ng/ml levels, J. Chromatogr. A 1055 (1
2) (2004) 185
190. [44] Y. Cai, G. Jiang, J. Liu, Q. Zhou, Multiwalled carbon nanotubes as a solid-phase extraction adsorbent for the determination of bisphenol A, 4-n-nonylphenol, and 4-tertoctylphenol, Anal. Chem. 75 (10) (2003) 2517
2521. [45] V.A. Lemos, L.S.G. Teixeira, M.D.A. Bezerra, A.C.S. Costa, J.T. Castro, L.A.M. Cardoso, et al., New materials for solid-phase extraction of trace elements, Appl. Spectrosc. Rev. 43 (4) (2008) 303
334. [46] P. Liang, Y. Liu, L. Guo, J. Zeng, H. Lu, Multiwalled carbon nanotubes as solid-phase extraction adsorbent for the preconcentration of trace metal ions and their determination by inductively coupled plasma atomic emission spectrometry, J. Anal. At. Spectrom. 19 (11) (2004) 1489
1492. [47] Q. Liu, J. Shi, J. Sun, T. Wang, L. Zeng, G. Jiang, Graphene and graphene oxide sheets supported on silica as versatile and high-performance adsorbents for solid-phase extraction, Angew. Chem. Int. Ed. 50 (26) (2011) 5913
5917. [48] S. Chigome, G. Darko, N. Torto, Electrospun nanofibers as sorbent material for solid phase extraction, Analyst 136 (14) (2011) 2879
2889. [49] J. Liu, A.G. Rinzler, H. Dai, J.H. Hafner, R.K. Bradley, P.J. Boul, et al., Fullerene pipes, Science 280 (5367) (1998) 1253
1256. [50] B.I. Yakobson, R.E. Smalley, Fullerene nanotubes, Am. Sci. 85 (4) (1997) 324
337. [51] R.H. Baughman, A.A. Zakhidov, W.A. De Heer, Carbon nanotubes—the route toward applications, Science 297 (5582) (2002) 787
792. [52] S. Iijima, T. Ichihashi, Single-shell carbon nanotubes of 1-nm diameter, Nature 363 (6430) (1993) 603. [53] M.S. Dresselhaus, G. Dresselhaus, R. Saito, A. Jorio, Raman spectroscopy of carbon nanotubes, Phys. Rep. 409 (2) (2005) 47
99. [54] V.N. Mochalin, O. Shenderova, D. Ho, Y. Gogotsi, The properties and applications of nanodiamonds, Nat. Nanotechnol. 7 (1) (2012) 11. [55] A.M. Schrand, S.A.C. Hens, O.A. Shenderova, Nanodiamond particles: properties and perspectives for bioapplications, Crit. Rev. Solid State Mater. Sci. 34 (1
2) (2009) 18
74. [56] A.K. Geim, Graphene: status and prospects, Science 324 (5934) (2009) 1530
1534. [57] D.R. Dreyer, S. Park, C.W. Bielawski, R.S. Ruoff, The chemistry of graphene oxide, Chem. Soc. Rev. 39 (1) (2010) 228
240. [58] Y. Zhu, S. Murali, W. Cai, X. Li, J.W. Suk, J.R. Potts, et al., Graphene and graphene oxide: synthesis, properties, and applications, Adv. Mater. 22 (35) (2010) 3906
3924. [59] A. Khan, J. Wang, J. Li, X. Wang, Z. Chen, A. Alsaedi, et al., The role of graphene oxide and graphene oxide-based nanomaterials in the removal of pharmaceuticals from aqueous media: a review, Environ. Sci. Pollut. Res. 24 (9) (2017) 7938
7958. [60] X. Chen, X. Hai, J. Wang, Graphene/graphene oxide and their derivatives in the separation/isolation and preconcentration of protein species: a review, Anal. Chim. Acta 922 (2016) 1
10. [61] X. Li, M. Rui, J. Song, Z. Shen, H. Zeng, Carbon and graphene quantum dots for optoelectronic and energy devices: a review, Adv. Funct. Mater. 25 (31) (2015) 4929
4947. [62] Y. Wang, S. Kalytchuk, Y. Zhang, H. Shi, S.V. Kershaw, A.L. Rogach, Thicknessdependent full-color emission tunability in a flexible carbon dot ionogel, J. Phys. Chem. Lett. 5 (8) (2014) 1412
1420.

406

Handbook of Nanomaterials in Analytical Chemistry

[63] G.W. Lee, J. Kim, J. Yoon, J.S. Bae, B.C. Shin, I.S. Kim, et al., Structural characterization of carboxylated multi-walled carbon nanotubes, Thin Solid Films 516 (17) (2008) 5781
5784. [64] K.K. Liu, C.L. Cheng, C.C. Chang, J.I. Chao, Biocompatible and detectable carboxylated nanodiamond on human cell, Nanotechnology 18 (32) (2007) 325102. [65] M. He, L. Huang, B. Zhao, B. Chen, B. Hu, Advanced functional materials in solid phase extraction for ICP-MS determination of trace elements and their species—a review, Anal. Chim. Acta 973 (2017) 1
24. [66] P. Sun, Y. Gao, C. Xu, Y. Lian, Determination of seven pyrethroid pesticide residues in vegetables by gas chromatography using carboxylated multi-walled carbon nanotubes as dispersion solid phase extraction sorbent, Food Addit. Contam., A 34 (12) (2017) 2164
2172. [67] S. Lo´pez-Feria, S. Ca´rdenas, M. Valca´rcel, One step carbon nanotubes-based solidphase extraction for the gas chromatographic
mass spectrometric multiclass pesticide control in virgin olive oils, J. Chromatogr. A 1216 (43) (2009) 7346
7350. [68] Y. Sun, W.Y. Zhang, J. Xing, C.M. Wang, Solid-phase microfibers based on modified single-walled carbon nanotubes for extraction of chlorophenols and organochlorine pesticides, Microchim. Acta 173 (1
2) (2011) 223
229. [69] P. Kueseng, J. Pawliszyn, Carboxylated multiwalled carbon nanotubes/polydimethylsiloxane, a new coating for 96-blade solid-phase microextraction for determination of phenolic compounds in water, J. Chromatogr. A 1317 (2013) 199
202. [70] L. Kou, R. Liang, Determination of tetrabromobisphenol A and bisphenol A in environmental water using carboxylated multiwalled carbon nanotubes as sorbent for solidphase extraction combined with liquid chromatography-tandem mass spectrometry, Se Pu 32 (8) (2014) 817
821. [71] C.K. Chang, C.C. Wu, Y.S. Wang, H.C. Chang, Selective extraction and enrichment of multiphosphorylated peptides using polyarginine-coated diamond nanoparticles, Anal. Chem. 80 (10) (2008) 3791
3797. [72] X. Kong, L.L. Huang, S.C.V. Liau, C.C. Han, H.C. Chang, Polylysine-coated diamond nanocrystals for MALDI-TOF mass analysis of DNA oligonucleotides, Anal. Chem. 77 (13) (2005) 4273
4277. [73] B. Sua´rez, B.M. Simonet, S. Ca´rdenas, M. Valca´rcel, Determination of non-steroidal anti-inflammatory drugs in urine by combining an immobilized carboxylated carbon nanotubes minicolumn for solid-phase extraction with capillary electrophoresis-mass spectrometry, J. Chromatogr. A 1159 (1
2) (2007) 203
207. [74] Y. Lv, Q. Deng, K.H. Row, T. Zhu, Silane coupling agents modified silica and graphene oxide materials for determination of sulfamerazine and sulfameter in milk by HPLC, Food Anal. Methods 12 (2018) 687
696. [75] R. Sitko, P. Janik, B. Feist, E. Talik, A. Gagor, Suspended aminosilanized graphene oxide nanosheets for selective preconcentration of lead ions and ultrasensitive determination by electrothermal atomic absorption spectrometry, ACS Appl. Mater. Interfaces 6 (22) (2014) 20144
20153. [76] K.J. Huang, J. Li, Y.M. Liu, L. Wang, Sensitive determination of polycyclic aromatic hydrocarbons in water samples by HPLC coupled with SPE based on graphene functionalized with triethoxysilane, J. Sep. Sci. 36 (4) (2013) 789
795. [77] P. Janik, B. Zawisza, E. Talik, R. Sitko, Selective adsorption and determination of hexavalent chromium ions using graphene oxide modified with amino silanes, Microchim. Acta 185 (2) (2018) 117.

Functionalized nanomaterials for sample preparation methods

407

[78] C. Xiao, S. Han, Z. Wang, J. Xing, C. Wu, Application of the polysilicone fullerene coating for solid-phase microextraction in the determination of semi-volatile compounds, J. Chromatogr. A 927 (1
2) (2001) 121
130. [79] J. Yu, L. Dong, C. Wu, L. Wu, J. Xing, Hydroxyfullerene as a novel coating for solidphase microextraction fiber with sol
gel technology, J. Chromatogr. A 978 (1
2) (2002) 37
48. [80] R.M. Vallant, Z. Szabo, S. Bachmann, R. Bakry, M. Najam-ul-Haq, M. Rainer, et al., Development and application of C60-fullerene bound silica for solid-phase extraction of biomolecules, Anal. Chem. 79 (21) (2007) 8144
8153. [81] R.M. Vallant, Z. Szabo, L. Trojer, M. Najam-ul-Haq, M. Rainer, C.W. Huck, et al., A new analytical material-enhanced laser desorption ionization (MELDI) based approach for the determination of low-mass serum constituents using fullerene derivatives for selective enrichment, J. Proteome Res. 6 (1) (2007) 44
53. [82] E.M. Soliman, H.M. Marwani, H.M. Albishri, Novel solid-phase extractor based on functionalization of multi-walled carbon nano tubes with 5-aminosalicylic acid for preconcentration of Pb(II) in water samples prior to determination by ICP-OES, Environ. Monit. Assess. 185 (12) (2013) 10269
10280. [83] M. Madadizadeh, M.A. Taher, H. Ashkenani, Determination of ultra-trace amounts of cadmium by ET-AAS after column preconcentration with a new sorbent of modified MWCNTs, Environ. Monit. Assess. 185 (5) (2013) 4097
4105. [84] S. Tajik, M.A. Taher, A new sorbent of modified MWCNTs for column preconcentration of ultra trace amounts of zinc in biological and water samples, Desalination 278 (1
3) (2011) 57
64. [85] D. Afzali, A. Mostafavi, Potential of modified multiwalled carbon nanotubes with 1-(2pyridylazo)-2-naphtol as a new solid sorbent for the preconcentration of trace amounts of cobalt (II) ion, Anal. Sci. 24 (9) (2008) 1135
1139. [86] A. Moghimi, S. Yousefi Siahkalrodi, Extraction and determination of Pb(II) by organic functionalisation of graphenes adsorbed on surfactant coated C18 in environmental sample, J. Chem. Health Risks 3 (3) (2018) 1
12. [87] C.J. Madadrang, H.Y. Kim, G. Gao, N. Wang, J. Zhu, H. Feng, et al., Adsorption behavior of EDTA-graphene oxide for Pb (II) removal, ACS Appl. Mater. Interfaces 4 (3) (2012) 1186
1193. [88] K. Pytlakowska, M. Matussek, B. Hachuła, M. Pilch, K. Kornaus, M. Zubko, et al., Graphene oxide covalently modified with 2,20 -iminodiacetic acid for preconcentration of Cr(III), Cu(II), Zn(II) and Pb(II) from water samples prior to their determination by energy dispersive X-ray fluorescence spectrometry, Spectrochim. Acta, B: At. Spectrosc. 147 (2018) 79
86. [89] X. Zhao, S. Zhang, C. Bai, B. Li, Y. Li, L. Wang, et al., Nano-diamond particles functionalized with single/double-arm amide
thiourea ligands for adsorption of metal ions, J. Colloid Interface Sci. 469 (2016) 109
119. [90] M. Ghaedi, M. Montazerozohori, N. Rahimi, M.N. Biysreh, Chemically modified carbon nanotubes as efficient and selective sorbent for enrichment of trace amount of some metal ions, J. Ind. Eng. Chem. 19 (5) (2013) 1477
1482. [91] M. Behbahani, T. Gorji, M. Mahyari, M. Salarian, A. Bagheri, A. Shaabani, Application of polypropylene amine dendrimers (POPAM)-grafted MWCNTs hybrid materials as a new sorbent for solid-phase extraction and trace determination of gold (III) and palladium (II) in food and environmental samples, Food Anal. Methods 7 (5) (2014) 957
966.

408

Handbook of Nanomaterials in Analytical Chemistry

[92] Z. Zhang, X. Yang, H. Zhang, M. Zhang, L. Luo, Y. Hu, et al., Novel molecularly imprinted polymers based on multi-walled carbon nanotubes with binary functional monomer for the solid-phase extraction of erythromycin from chicken muscle, J. Chromatogr. B 879 (19) (2011) 1617
1624. [93] F. Tan, M. Deng, X. Liu, H. Zhao, X. Li, X. Quan, et al., Evaluation of a novel microextraction technique for aqueous samples: porous membrane envelope filled with multiwalled carbon nanotubes coated with molecularly imprinted polymer, J. Sep. Sci. 34 (6) (2011) 707
715. [94] X. Chen, Z. Zhang, X. Yang, Y. Liu, J. Li, M. Peng, et al., Novel molecularly imprinted polymers based on multiwalled carbon nanotubes with bifunctional monomers for solid-phase extraction of rhein from the root of kiwi fruit, J. Sep. Sci. 35 (18) (2012) 2414
2421. [95] R.W. Kibechu, S. Sampath, B.B. Mamba, T.A.M. Msagati, Graphene-based molecularly imprinted polymer for separation and pre-concentration of trace polycyclic aromatic hydrocarbons in environmental water samples, J. Appl. Polym. Sci. 134 (37) (2017). Available from: https://doi.org/10.1002/APP.45300. [96] R. Sedghi, B. Heidari, M. Yassari, Novel molecularly imprinted polymer based on β-cyclodextrin@ graphene oxide: synthesis and application for selective diphenylamine determination, J. Colloid Interface Sci. 503 (2017) 47
56. [97] L. Cheng, S. Pan, C. Ding, J. He, C. Wang, Dispersive solid-phase microextraction with graphene oxide based molecularly imprinted polymers for determining bis(2ethylhexyl) phthalate in environmental water, J. Chromatogr. A 1511 (2017) 85
91. [98] G. Liang, H. Zhai, L. Huang, X. Tan, Q. Zhou, X. Yu, et al., Synthesis of carbon quantum dots-doped dummy molecularly imprinted polymer monolithic column for selective enrichment and analysis of aflatoxin B1 in peanut, J. Pharm. Biomed. Anal. 149 (2018) 258
264. [99] Z.A. ALOthman, M. Habila, E. Yilmaz, M. Soylak, Solid phase extraction of Cd(II), Pb(II), Zn(II) and Ni(II) from food samples using multiwalled carbon nanotubes impregnated with 4-(2-thiazolylazo) resorcinol, Microchim. Acta 177 (3
4) (2012) 397
403. [100] M.A. Habila, E. Yilmaz, Z.A. AlOthman, M. Soylak, 1-Nitroso-2-naphthol impregnated multiwalled carbon nanotubes (NNMWCNTs) for the separation-enrichment and flame atomic absorption spectrometric detection of copper and lead in hair, water, and food samples, Desalin. Water Treat. 87 (2017) 285
291. [101] A.A. Gouda, S.M. Al Ghannam, Impregnated multiwalled carbon nanotubes as efficient sorbent for the solid phase extraction of trace amounts of heavy metal ions in food and water samples, Food Chem. 202 (2016) 409
416. [102] M. Soylak, Z. Topalak, Multiwalled carbon nanotube impregnated with tartrazine: solid phase extractant for Cd(II) and Pb(II), J. Ind. Eng. Chem. 20 (2) (2014) 581
585. [103] E. Sahmetlioglu, E. Yilmaz, E. Aktas, M. Soylak, Polypyrrole/Multi-walled carbon nanotube composite for the solid phase extraction of lead(II) in water samples, Talanta 119 (2014) 447
451. [104] M. Chen, Y. Lin, C. Gu, J. Wang, Arsenic sorption and speciation with branchpolyethyleneimine modified carbon nanotubes with detection by atomic fluorescence spectrometry, Talanta 104 (2013) 53
57. [105] M.R. Nabid, R. Sedghi, A. Bagheri, M. Behbahani, M. Taghizadeh, H.A. Oskooie, et al., Preparation and application of poly(2-amino thiophenol)/MWCNTs nanocomposite for adsorption and separation of cadmium and lead ions via solid phase extraction, J. Hazard. Mater. 203 (2012) 93
100.

Functionalized nanomaterials for sample preparation methods

409

[106] C. Zhang, Z. Zhang, G. Li, Preparation of sulfonated graphene/polypyrrole solidphase microextraction coating by in situ electrochemical polymerization for analysis of trace terpenes, J. Chromatogr. A 1346 (2014) 8
15. [107] S.Q. Han, C.H. Xiao, C.Y. Wu, Properties of polysilicone fullerene as the coating for solid-phase microextraction, Chin. J. Anal. Chem. 29 (12) (2001) 1374
1378. [108] J. Zhang, L. Yang, M. Wu, X. Guo, B. Zeng, F. Zhao, Electrochemical preparation of poly(3-methylthiophene-carbazole)/graphene oxide composite coating for the highly effective solid-phase microextraction of some fragrance, Talanta 171 (2017) 61
67. [109] M. Behzadi, M. Mirzaei, Poly(o-anisidine)/Graphene oxide nanosheets composite as a coating for the headspace solid-phase microextraction of benzene, toluene, ethylbenzene and xylenes, J. Chromatogr. A 1443 (2016) 35
42. [110] M.H. Kojidi, A. Aliakbar, A graphene oxide based poly(2,6-diaminopyridine) composite for solid-phase extraction of Cd(II) prior to its determination by FAAS, Microchim. Acta 184 (8) (2017) 2855
2860. [111] B. Hashemi, P. Zohrabi, S. Dehdashtian, Application of green solvents as sorbent modifiers in sorptive-based extraction techniques for extraction of environmental pollutants, TrAC Trends Anal. Chem. 109 (2018) 50
61. ˚ . Jo¨nsson, M.J. Wen, Disposable ionic liquid [112] J.F. Liu, N. Li, G.B. Jiang, J.M. Liu, J.A coating for headspace solid-phase microextraction of benzene, toluene, ethylbenzene, and xylenes in paints followed by gas chromatography
flame ionization detection, J. Chromatogr. A 1066 (1
2) (2005) 27
32. [113] L. Li, M. Wu, Y. Feng, F. Zhao, B. Zeng, Doping of three-dimensional porous carbon nanotube-graphene-ionic liquid composite into polyaniline for the headspace solidphase microextraction and gas chromatography determination of alcohols, Anal. Chim. Acta 948 (2016) 48
54. [114] Y. Zhang, Y.G. Zhao, W.S. Chen, H.L. Cheng, X.Q. Zeng, Y. Zhu, Threedimensional ionic liquid-ferrite functionalized graphene oxide nanocomposite for pipette-tip solid phase extraction of 16 polycyclic aromatic hydrocarbons in human blood sample, J. Chromatogr. A 1552 (2018) 1
9. [115] H. Zhang, X. Wu, Y. Yuan, D. Han, F. Qiao, H. Yan, An ionic liquid functionalized graphene adsorbent with multiple adsorption mechanisms for pipette-tip solid-phase extraction of auxins in soybean sprouts, Food Chem. 265 (2018) 290
297. [116] S. Hamidi, A. Azami, E.M. Aghdam, A novel mixed hemimicelles dispersive microsolid phase extraction using ionic liquid functionalized magnetic graphene oxide/polypyrrole for extraction and pre-concentration of methotrexate from urine samples followed by the spectrophotometric method, Clin. Chim. Acta 488 (2019) 179
188. [117] Y. Zhang, H. Zhou, Z.H. Zhang, X.L. Wu, W.G. Chen, Y. Zhu, et al., Threedimensional ionic liquid functionalized magnetic graphene oxide nanocomposite for the magnetic dispersive solid phase extraction of 16 polycyclic aromatic hydrocarbons in vegetable oils, J. Chromatogr. A 1489 (2017) 29
38. [118] J. Wu, H. Zhao, D. Xiao, P.H. Chuong, J. He, H. He, Mixed hemimicelles solid-phase extraction of cephalosporins in biological samples with ionic liquid-coated magnetic graphene oxide nanoparticles coupled with high-performance liquid chromatographic analysis, J. Chromatogr. A 1454 (2016) 1
8. [119] A.P. Abbott, G. Capper, D.L. Davies, R.K. Rasheed, V. Tambyrajah, Novel solvent properties of choline chloride/urea mixtures, Chem. Commun. 1 (2003) 70
71. [120] L. Liu, W. Tang, B. Tang, D. Han, K.H. Row, T. Zhu, Pipette-tip solid-phase extraction based on deep eutectic solvent modified graphene for the determination of sulfamerazine in river water, J. Sep. Sci. 40 (9) (2017) 1887
1895.

410

Handbook of Nanomaterials in Analytical Chemistry

[121] X. Wang, G. Li, K.H. Row, Graphene and graphene oxide modified by deep eutectic solvents and ionic liquids supported on silica as adsorbents for solid-phase extraction, Bull. Korean Chem. Soc. 38 (2) (2017) 251
257. [122] S.M. Yousefi, F. Shemirani, S.A. Ghorbanian, Deep eutectic solvent magnetic bucky gels in developing dispersive solid phase extraction: application for ultra trace analysis of organochlorine pesticides by GC-micro ECD using a large-volume injection technique, Talanta 168 (2017) 73
81. [123] M. Tuzen, K.O. Saygi, C. Usta, M. Soylak, Pseudomonas aeruginosa immobilized multiwalled carbon nanotubes as biosorbent for heavy metal ions, Bioresour. Technol. 99 (6) (2008) 1563
1570. [124] N. Aydemir, N. Tokman, A.T. Akarsubasi, A. Baysal, S. Akman, Determination of some trace elements by flame atomic absorption spectrometry after preconcentration and separation by Escherichia coli immobilized on multiwalled carbon nanotubes, Microchim. Acta 175 (1
2) (2011) 185. [125] S. Ozdemir, E. Kilinc, K.S. Celik, V. Okumus, M. Soylak, Simultaneous preconcentrations of Co21, Cr61, Hg21 and Pb21 ions by Bacillus altitudinis immobilized nanodiamond prior to their determinations in food samples by ICP-OES, Food Chem. 215 (2017) 447
453. [126] F. Pena-Pereira, R.M. Duarte, A.C. Duarte, Immobilization strategies and analytical applications for metallic and metal-oxide nanomaterials on surfaces, TrAC, Trends Anal. Chem. 40 (2012) 90
105. [127] J. Krenkova, F. Foret, Iron oxide nanoparticle coating of organic polymer-based monolithic columns for phosphopeptide enrichment, J. Sep. Sci. 34 (16
17) (2011) 2106
2112. [128] M. Inuta, R. Arakawa, H. Kawasaki, Analyst (Cambridge, UK) 136 (2011) 1167. [129] W. Lu, Y. Luo, G. Chang, F. Liao, X. Sun, Layer-by-layer self-assembly of multilayer films of polyelectrolyte/Ag nanoparticles for enzymeless hydrogen peroxide detection, Thin Solid Films 520 (1) (2011) 554
557. [130] X. Hu, W. Cheng, T. Wang, Y. Wang, E. Wang, S. Dong, Fabrication, characterization, and application in SERS of self-assembled polyelectrolyte
gold nanorod multilayered films, J. Phys. Chem. B 109 (41) (2005) 19385
19389. [131] Y. Wei, M. Li, S. Jiao, Q. Huang, G. Wang, B. Fang, Fabrication of CeO2 nanoparticles modified glassy carbon electrode and its application for electrochemical determination of UA and AA simultaneously, Electrochim. Acta 52 (3) (2006) 766
772. [132] D.D. Cao, J.X. Lu¨, J.F. Liu, G.B. Jiang, In situ fabrication of nanostructured titania coating on the surface of titanium wire: a new approach for preparation of solid-phase microextraction fiber, Anal. Chim. Acta 611 (1) (2008) 56
61. [133] S. Baruah, J. Dutta, Hydrothermal growth of ZnO nanostructures, Sci. Technol. Adv. Mater. 10 (1) (2009) 013001. [134] C. Cheng, B. Yan, S.M. Wong, X. Li, W. Zhou, T. Yu, et al., Fabrication and SERS performance of silver-nanoparticle-decorated Si/ZnO nanotrees in ordered arrays, ACS Appl. Mater. Interfaces 2 (7) (2010) 1824
1828. [135] N. Kohler, G.E. Fryxell, M. Zhang, A bifunctional poly(ethylene glycol) silane immobilized on metallic oxide-based nanoparticles for conjugation with cell targeting agents, J. Am. Chem. Soc. 126 (23) (2004) 7206
7211. [136] S. Deki, Y. Aoi, J. Okibe, H. Yanagimoto, A. Kajinami, M. Mizuhata, J. Mater. Chem. 7 (1997) 1769. [137] B. Lin, T. Li, Y. Zhao, F.K. Huang, L. Guo, Y.Q. Feng, J. Chromatogr., A 1192 (2008) 95.

Functionalized nanomaterials for sample preparation methods

411

[138] T. Li, Y. Xu, Y.Q. Feng, J. Liq. Chromatogr. Relat. Technol. 32 (2009) 2484. [139] Z. Zhang, S. Dai, D.A. Blom, J. Shen, Synthesis of ordered metallic nanowires inside ordered mesoporous materials through electroless deposition, Chem. Mater. 14 (3) (2002) 965
968. [140] W. Wang, N. Li, X. Li, W. Geng, S. Qiu, Synthesis of metallic nanotube arrays in porous anodic aluminum oxide template through electroless deposition, Mater. Res. Bull. 41 (8) (2006) 1417
1423. [141] K. Nielsch, F. Mu¨ller, A.P. Li, U. Go¨sele, Uniform nickel deposition into ordered alumina pores by pulsed electrodeposition, Adv. Mater. 12 (8) (2000) 582
586. [142] K. Jiang, Q. Huang, K. Fan, L. Wu, D. Nie, W. Guo, et al., Reduced graphene oxide and gold nanoparticle composite-based solid-phase extraction coupled with ultra-highperformance liquid chromatography-tandem mass spectrometry for the determination of 9 mycotoxins in milk, Food Chem. 264 (2018) 218
225. [143] M.J. Trujillo-Rodrı´guez, J.L. Anderson, Silver-based polymeric ionic liquid sorbent coatings for solid-phase microextraction: materials for the selective extraction of unsaturated compounds, Anal. Chim. Acta 1047 (2019) 52
61. [144] M.N. Yazdi, Y. Yamini, H. Asiabi, Fabrication of polypyrrole-silver nanocomposite for hollow fiber solid phase microextraction followed by HPLC/UV analysis for determination of parabens in water and beverages samples, J. Food Compos. Anal. 74 (2018) 18
26. [145] Y. Yang, P. Qin, J. Zhang, W. Li, J. Zhu, M. Lu, et al., Fabrication of nanoscale graphitic carbon nitride/copper oxide hybrid composites coated solid-phase microextraction fibers coupled with gas chromatography for determination of polycyclic aromatic hydrocarbons, J. Chromatogr. A 1570 (2018) 47
55. [146] M. Ghani, S.M. Ghoreishi, S. Masoum, Highly porous nanostructured copper oxide foam fiber as a sorbent for head space solid-phase microextraction of BTEX from aqueous solutions, Microchem. J. 145 (2019) 210
217. [147] M.N. Yazdi, Y. Yamini, H. Asiabi, Multiwall carbon nanotube-zirconium oxide nanocomposite hollow fiber solid phase microextraction for determination of polyaromatic hydrocarbons in water, coffee and tea samples, J. Chromatogr. A 1554 (2018) 8
15. [148] P.J. Robinson, P. Dunnill, M.D. Lilly, The properties of magnetic supports in relation to immobilized enzyme reactors, Biotechnol. Bioeng. 15 (3) (1973) 603
606. ˇ r´ıkova´, I. Safaˇ ˇ r´ık, Magnetic solid-phase extraction, J. Magn. Magn. Mater. 194 [149] M. Safaˇ (1
3) (1999) 108
112. [150] Q.A. Pankhurst, J. Connolly, S.K. Jones, J. Dobson, Applications of magnetic nanoparticles in biomedicine, J. Phys. D: Appl. Phys. 36 (13) (2003) R167. [151] S. Laurent, D. Forge, M. Port, A. Roch, C. Robic, L. Vander Elst, et al., Magnetic iron oxide nanoparticles: synthesis, stabilization, vectorization, physicochemical characterizations, and biological applications, Chem. Rev. 108 (6) (2008) 2064
2110. [152] R.H. Kodama, Magnetic nanoparticles, J. Magn. Magn. Mater. 200 (1
3) (1999) 359
372. [153] S. Sadeghi, H. Azhdari, H. Arabi, A.Z. Moghaddam, Surface modified magnetic Fe3O4 nanoparticles as a selective sorbent for solid phase extraction of uranyl ions from water samples, J. Hazard. Mater. 215 (2012) 208
216. [154] S. Christophoridou, P. Dais, L.H. Tseng, M. Spraul, Separation and identification of phenolic compounds in olive oil by coupling high-performance liquid chromatography with postcolumn solid-phase extraction to nuclear magnetic resonance spectroscopy (LC-SPE-NMR), J. Agric. Food. Chem. 53 (12) (2005) 4667
4679.

412

Handbook of Nanomaterials in Analytical Chemistry

[155] C. Clarkson, D. Stærk, S.H. Hansen, J.W. Jaroszewski, Hyphenation of solid-phase extraction with liquid chromatography and nuclear magnetic resonance: application of HPLC-DAD-SPE-NMR to identification of constituents of Kanahia laniflora, Anal. Chem. 77 (11) (2005) 3547
3553. [156] D. Xiao, C. Zhang, D. Yuan, J. He, J. Wu, K. Zhang, et al., Magnetic solid-phase extraction based on Fe3O4 nanoparticle retrieval of chitosan for the determination of flavonoids in biological samples coupled with high performance liquid chromatography, RSC Adv. 4 (110) (2014) 64843
64854. [157] G. Miliauskas, T.A. van Beek, P. de Waard, R.P. Venskutonis, E.J. Sudho¨lter, Comparison of analytical and semi-preparative columns for high-performance liquid chromatography
solid-phase extraction
nuclear magnetic resonance, J. Chromatogr. A 1112 (1
2) (2006) 276
284. [158] J.J. Xu, L.H. Ye, J. Cao, W. Cao, Q.Y. Zhang, Ultramicro chitosan-assisted in-syringe dispersive micro-solid-phase extraction for flavonols from healthcare tea by ultra-high performance liquid chromatography, J. Chromatogr. A 1409 (2015) 11
18. [159] E. Tahmasebi, Y. Yamini, Facile synthesis of new nano sorbent for magnetic solidphase extraction by self assembling of bis-(2,4,4-trimethyl pentyl)-dithiophosphinic acid on Fe3O4@Ag core@shell nanoparticles: characterization and application, Anal. Chim. Acta 756 (2012) 13
22. [160] A. Asfaram, M. Ghaedi, H. Javadian, A. Goudarzi, Cu- and S-@SnO2 nanoparticles loaded on activated carbon for efficient ultrasound assisted dispersive μSPE-spectrophotometric detection of quercetin in Nasturtium officinale extract and fruit juice samples: CCD-RSM design, Ultrason. Sonochem. 47 (2018) 1
9. [161] A. Michalkiewicz, M. Biesaga, K. Pyrzynska, Solid-phase extraction procedure for determination of phenolic acids and some flavonols in honey, J. Chromatogr. A 1187 (1
2) (2008) 18
24. [162] Y. Tahtah, S.G. Wubshet, K.T. Kongstad, A.M. Heskes, I. Pateraki, B.L. Møller, et al., High-resolution PTP1B inhibition profiling combined with high-performance liquid chromatography
high-resolution mass spectrometry
solid-phase extraction
nuclear magnetic resonance spectroscopy: proof-of-concept and antidiabetic constituents in crude extract of Eremophila lucida, Fitoterapia 110 (2016) 52
58. [163] C. Clarkson, M. Sibum, R. Mensen, J.W. Jaroszewski, Evaluation of on-line solidphase extraction parameters for hyphenated, high-performance liquid chromatography
solid-phase extraction
nuclear magnetic resonance applications, J. Chromatogr. A 1165 (1
2) (2007) 1
9. [164] M. Safarikova, I. Safarik, Magnetic solid-phase extraction of target analytes from large volumes of urine, Eur. Cells Mater. 3 (Suppl. 2) (2002) 192
195. [165] M. Safarikova, I. Kibrikova, L. Ptackova, T. Hubka, K. Komarek, I. Safarik, Magnetic solid phase extraction of non-ionic surfactants from water, J. Magn. Magn. Mater. 293 (1) (2005) 377
381. [166] C. Huang, B. Hu, Silica-coated magnetic nanoparticles modified with γ-mercaptopropyltrimethoxysilane for fast and selective solid phase extraction of trace amounts of Cd, Cu, Hg, and Pb in environmental and biological samples prior to their determination by inductively coupled plasma mass spectrometry, Spectrochim. Acta, B: At. Spectrosc. 63 (3) (2008) 437
444. [167] H.M. Kim, M. Uh, D.H. Jeong, H.Y. Lee, J.H. Park, S.K. Lee, Localized surface plasmon resonance biosensor using nanopatterned gold particles on the surface of an optical fiber, Sens. Actuators, B: Chem. 280 (2019) 183
191.

Functionalized nanomaterials for sample preparation methods

413

[168] H. Li, H. Li, Z. Chen, J. Lin, On-chip solid phase extraction coupled with electrophoresis using modified magnetic microspheres as stationary phase, Sci. China Ser. B: Chem. 52 (12) (2009) 2287. [169] Q. Cheng, F. Qu, N.B. Li, H.Q. Luo, Mixed hemimicelles solid-phase extraction of chlorophenols in environmental water samples with 1-hexadecyl-3-methylimidazolium bromide-coated Fe3O4 magnetic nanoparticles with high-performance liquid chromatographic analysis, Anal. Chim. Acta 715 (2012) 113
119. [170] H.M. Jiang, Z.P. Yan, Y. Zhao, X. Hu, H.Z. Lian, Zincon-immobilized silica-coated magnetic Fe3O4 nanoparticles for solid-phase extraction and determination of trace lead in natural and drinking waters by graphite furnace atomic absorption spectrometry, Talanta 94 (2012) 251
256. [171] C. Cui, M. He, B. Chen, B. Hu, Chitosan modified magnetic nanoparticles based solid phase extraction combined with ICP-OES for the speciation of Cr(III) and Cr(VI), Anal. Methods 6 (21) (2014) 8577
8583. [172] Y. Wang, J. Xie, Y. Wu, X. Hu, A magnetic metal-organic framework as a new sorbent for solid-phase extraction of copper(II), and its determination by electrothermal AAS, Microchim. Acta 181 (9
10) (2014) 949
956. [173] S. Azodi-Deilami, A.H. Najafabadi, E. Asadi, M. Abdouss, D. Kordestani, Magnetic molecularly imprinted polymer nanoparticles for the solid-phase extraction of paracetamol from plasma samples, followed its determination by HPLC, Microchim. Acta 181 (15
16) (2014) 1823
1832.

Further reading S. Goyanes, G.R. Rubiolo, A. Salazar, A. Jimeno, M.A. Corcuera, I. Mondragon, Carboxylation treatment of multiwalled carbon nanotubes monitored by infrared and ultraviolet spectroscopies and scanning probe microscopy, Diamond Relat. Mater. 16 (2) (2007) 412
417. ´ . Me´ndez, J.B. Garcı´a, S.G. Martı´n, R.P. Crecente, Carbon nanotubes as C.H. Latorre, J.A solid-phase extraction sorbents prior to atomic spectrometric determination of metal species: a review, Anal. Chim. Acta 749 (2012) 16
35.

Surface-modified metal nanoparticles for recognition of toxic organic molecules

16

Suresh Kumar Kailasa1, Rakesh Kumar Singhal2, Hirakendu Basu2 and Tae Jung Park3 1 Department of Applied Chemistry, S. V. National Institute of Technology, Surat, India, 2 Analytical Chemistry Division, Bhabha Atomic Research Center, Trombay, Mumbai, India, 3 Department of Chemistry, Institute of Interdisciplinary Convergence Research, Research Institute of Halal Industrialization Technology, Chung-Ang University, 84 Heukseok-ro, Dongjak-Gu, Seoul, Republic of Korea

16.1

Introduction

In recent years, noble metal nanoparticles (NPs) have shown tremendous applications in the development of facile analytical methods for assaying of wide variety chemical species [1 13], since noble metal NPs exhibit surface plasmons, leading to strong interactions with electromagnetic radiation, which allow them to use as promising probes for the detection and preconcentration of wide variety analytes [3,4]. As we know that metal NPs surfaces get negative and positive imaginary dielectric constant by interacting with electromagnetic radiation, inducing collective oscillation of electrons, which can be referred as surface plasmons [6]. As a result, noble metal NPs are responsible to exhibit bright colors because of surface plasmons. In view of this, great research has been carried out on especially silver (Ag) and gold (Au) NPs as probes for recognition of wide variety chemical species via visual changes [6]. To make Ag and Au NPs as specific probes for recognition of chemical species, Ag and Au metal NPs surfaces should be modified with specific organic or biomolecules, dictating their analytical applications, which allows to develop economical and facile probes for assaying of chemical species with high sensitivity [8]. Generally, molecular recognition by Ag and Au NPs mainly depends on the surface modification of Ag and Au NPs surfaces [2,3]. Several reviews and research papers have been illustrated the significant advantages of Ag and Au NPs surface modifications for molecular recognitions via visible color change [2 10]. In this chapter, we summarize recent progress on the molecular recognitions of pesticides by the functional Ag and Au NPs. In this chapter, we focused on the surface modification of Ag and Au NPs for colorimetric assaying of pesticides via analytes-induced Ag and Au NPs aggregations. To summarize the potential Handbook of Nanomaterials in Analytical Chemistry. DOI: https://doi.org/10.1016/B978-0-12-816699-4.00016-5 Copyright © 2020 Elsevier Inc. All rights reserved.

416

Handbook of Nanomaterials in Analytical Chemistry

applications of Ag and Au NPs in molecular recognitions, specific examples of colorimetric sensing mechanisms using color change and red-shift in surface plasmon resonance (SPR) have discussed and tabulated. Finally, this chapter provides summary and prospective of functional Ag and Au NPs for molecular recognition of various pesticides.

16.2

Colorimetric recognition of pesticides by surfacemodified Ag nanoparticles

To enhance the crap yields of various craps, pesticides are significantly used in agriculture fields to protect from the various insecticides. However, overuses of pesticides causes serious toxic effects on human health and environment [14]. Further, pesticides and their metabolites cause several diseases such as birth defects, infertility, and cancer, respectively. In this connection, it is essentially need to measure low concentration of pesticides in various complex matrices. Wide variety of pesticides has been introduced by various manufacturing companies, which causes significant contamination of environment and food stuffs. Thus various traditional analytical techniques including gas chromatography (GC), high-performance liquid chromatography (HPLC), GC mass spectrometry, and HPLC mass spectrometric techniques have been applied to detect and quantify the pesticides residues in various samples [15]. However, these method need skilled personnel, and they are expensive instruments, which may not be suitable for real-time and on-site detection at minimal volume of samples. To overcome these problems, functional Ag and Au NPs have been widely used as probes for colorimetric recognition of wide variety of pesticides in various samples. Briefly, silver NPs were functionalized with p-sulfonatocalix[n]arene (pSC) (n 5 4, 8) for colorimetric recognition of optunal [16]. In this work, the authors explored the selectivity of pSC8- and pSC4-moieties on the surfaces of Ag NPs, revealing the pSC4 Ag NPs was selectively interacted with optunal, which results the red-shift and color change from yellow to red. This sensing mechanism was mainly attributed due to the host guest interaction (cation π or π π or electrostatic interactions). Similarly, dimethoate was selectively induced the aggregation of pSC4 Ag NPs, allowing remarkable spectral shift and color change, which can be used as a probe for colorimetric detection of dimethoate [17]. This sensing mechanism also is based on the host guest interactions between pSC4 Ag NPs and dimethoate. The colorimetric sensing ability of Ag NPs has been tuned by modifying their surfaces with various organic moieties. For example, our groups functionalized Ag NPs with various organic molecules including 5-sulfo anthranilic acid dithiocarbamate [18], cyclen dithiocarbamate [19], 4-aminobenzenethiol [20], dopamine dithiocarbamate [21], 3-mercaptopropinonic acid and guanidine acetic acid [22], and 2-mercapto-5-nitrobenzimidazole [23] and used them as promising probes for colorimetric recognition of various pesticides (tricyclazole fungicide, thiram and paraquat, carbendazim, mancozeb, and glyphosate in water, rice and food samples).

Surface-modified metal nanoparticles for recognition of toxic organic molecules

417

All these methods revealed that the characteristic SPR peak of functionalized Ag NPs was remarkably red-shifted with longer wavelengths, yielding a significant color change from yellow to different colors (orange-red or pink or green or red), which confirm the aggregation of functionalized Ag NPs induced by specific pesticides. These colorimetric recognitions were based on the aggregation of functionalized Ag NPs induced by target pesticides via various noncovalent interactions (electrostatic, host guest, hydrogen-bonding, and π π). For example, 4aminobenzenethiol (ABT) functionalized Ag NPs were aggregated by the addition of carbendazim via noncovalent interactions between functionalized Ag NPs and carbendazim (Fig. 16.1). Then the distance of carbendazim-conjugated ABT-Ag NPs was greatly reduced due to the π π interactions, resulting aggregation of Ag NPs, which yields a specific color from yellow to orange. These functionalized Ag NPs based colorimetric recognition methods exhibited wider linearity in the ranges of micromolar to nanomolar with lower detection limits. As shown in Fig. 16.2, mancozeb induces significant spectral shift and color changes of Ag NPs, allowing to quantify mancozeb by UV visible spectrometry, which can be noticed with naked eye. The absorption ratio at 620 and 394 nm (A620/A394) was progressively increased with increasing concentration of mancozeb (5 3 1025 3 3 1024 M), exhibiting linear correlation (y 5 0.2701 ln(x) 1 1.5969, R2 5 0.9937) with detection limit of 21.1 3 1026 M, which is lower than that of the maximum mancozeb residues limit (0.1 mg L21, 9.4 3 1025 M) by Codex [24]. These methods were successfully applied for the detection of target pesticides in waters, rice, wheat, and vegetable samples with high accuracy and precision. Importantly, these developed probes exhibited high selectivity for colorimetric recognition of target pesticides even in the presence of mixture of pesticides or inorganic species. Recently, several reports explored that the potential applications of Ag NPs for colorimetric recognition of various pesticides in food samples. Briefly, prothioconazole was effectively visualized (yellow to pink-orange) by the aggregation of unmodified-Ag NPs [25]. The authors observed that the linear relationship was observed between the absorbance ratio (A500/A395) and the concentration of prothioconazole, exhibiting lower detection limit of 1.7 ng mL21. This method was successfully applied to quantify prothioconazole in paddy water and wheat flour sample. Further, citrate (Cit)-capped Ag NPs was used as a recognition element for the colorimetric detection of triazophos via aggregation of Cit-Ag NPs [26]. It was noticed that the characteristic yellow color of Cit-Ag NPs was gradually changed to prunosus with increasing concentration of triazophos, confirming the aggregation of Cit-Ag NPs induced by triazophos, which is due to the noncovalent interactions. The developed method exhibited good recovery ranges from 82% to 100.8% and successfully applied to detect triazophos in environmental samples. Zheng’s group was assembled thioglycolic acid (TGA) on the surfaces of Ag NPs for colorimetric recognition of 6-benzylaminopurine (6-BAP) [27]. The TGA Ag NPs were effectively aggregated upon the addition of 6-BAP, revealing the formation of large conjugated nanostructures via noncovalent interactions (π π interactions and hydrogen-bonding). This method exhibited good linearity and successfully used as promising method for the detection of 6-BAP in water and vegetables. Similarly,

Figure 16.1 Colorimetric sensing of carbendazim using ABT functionalized Ag NPs as a colorimetric recognition probe. NPs, Nanoparticles. Source: Reprinted from G.M. Patel, J.V. Rohit, R.K. Singhal, S.K. Kailasa, Recognition of carbendazim fungicide in environmental samples by using 4-aminobenzenethiol functionalized silver nanoparticles as a colorimetric sensor, Sensor Actuat. B Chem. 206 (2015) 684 691 with permission.

Surface-modified metal nanoparticles for recognition of toxic organic molecules

419

Figure 16.2 (A) Absorption spectra of dopamine dithiocarbamate (DDTC)-Ag NPs with different pesticides (1023 M) at Tris HCl pH 9.0. (B) Photographic images of corresponding solutions. NPs, Nanoparticles. Source: Reprinted from J.V. Rohit, J.N. Solanki, S.K. Kailasa, Surface modification of silver nanoparticles with dopamine dithiocarbamate for selective colorimetric sensing of mancozeb in environmental samples, Sens. Actuators, B: Chem. 200 (2014) 219 226 with permission.

the same group explored the recognition ability of Cit-Ag NPs for the colorimetric detection of thiophanate-methyl [28]. The authors noticed that the remarkable redshift in the SPR peak from 394 to 525 nm upon the addition of thiophanate-methyl, which yields a color change from yellow to cherry red. Under the optimum conditions, the absorption ratio (A525/A394) showed good linearity with increasing thiophanate-methyl concentration ranging from 2 to 100 μM, with the detection limit of 0.12 μM. The authors applied the developed method for the detection of thiophanate-methyl in environmental samples. Li’s group developed a facile and novel colorimetric method for the recognition of dipterex by using Cit-Ag NPs as a probe and acetylthiocholine (ATCh) as a reagent [29]. In this work, the color of

420

Handbook of Nanomaterials in Analytical Chemistry

Cit-Ag NPs was changed to pink by the catalytic reaction of acetylcholinesterase (AChE), yielding to generate thiocholine (TCh), which allows the aggregation of Cit-Ag NPs. UV visible spectrometry was used for the quantitative detection of dipterex by plotting graph between the absorbance ratio (A396/A520) and the concentration of dipterex (0.25 37.5 ng mL21), which exhibits the limit of detection (LOD) of 0.18 ng mL21. The authors successfully analyzed dipterex in environmental water samples. Recently, Ag NPs were functionalized with sucrose for colorimetric recognition of endrin in food and water samples [30]. The sucrose-functionalized Ag NPs acted as stereoselective sensor for specific detection of endrin. In this method, a new localized SPR (LSPR) peak of sucrose-Ag NPs was generated upon the addition of endrin, confirming the aggregation of sucrose-Ag NPs induced by endrin. The developed probe was effectively worked at pH 7.0 in the presence of water and acetone ratio at 7:3. The characteristic yellow color of sucrose-Ag NPs was changed to pink color due to the aggregation of Ag NPs via the replacement of sucrose molecules with endrin, since endrin is an electron-rich molecule that strongly binds with the Ag NPs surfaces at endo-position of endrin, which results the remarkable shift in the LSPR peak of sucrose-Ag NPs. This method exhibited good linearity in the range of 0.05 5.00 μg mL21, with LOD of 0.015 μg mL21. Further, good recoveries (90% 97%) were observed for the detection of endrin in water and food samples. Similarly, Ag NPs have been used as promising colorimetric sensor for the detection of diazinon in vegetables and fruits [31]. It was noticed that the yellow color of Ag NPs was turned into pinkish-red color by the addition of diazinon, confirming the aggregation of Ag NPs via noncovalent interactions. The authors investigated the morphology of Ag NPs in the presence and absence of diazinon by transmission electron microscopy (TEM), revealing the dispersion state of Ag NPs was changed to aggregation due to the addition of diazinon, which signifies that Ag NPs act as a specific sensor for the recognition of diazinon. This method was successfully applied to quantify diazinon in vegetables (apple, beans, grapes, and potato). Table 16.1 illustrates the analytical features of functional Ag NPs for colorimetric assay of various pesticides in water and food samples.

16.3

Colorimetric recognition of pesticides by surface-modified Au nanoparticles

In recent years, functional gold (Au) NPs have figuratively explored the potential applications in the development of miniaturized colorimetric methods for specific recognition of trace-level target chemical species [8], since they exhibited unique optoelectronics properties, especially the SPR band, which makes them as prominent probes in quantifying the target analytes via analyte-induced aggregation. Importantly, the remarkable red-shift in the SPR peak yields a noticeable color change based on their dispersion (red color) and aggregation (blue color), which can be visualized with naked eye. As a result, a plethora of research reports has

Table 16.1 Functional Ag nanoparticles (NPs) as probes for colorimetric recognition of pesticides. Functional Ag NPs

SPR peak (nm)

Size (nm)

Analyte

Linear range

Limit of detection

Reference

p-Sulfonatocalix[n]arene Ag NPs pSC4 Ag NPs 5-Sulfo anthranilic acid dithiocarbamate Ag NPs Cyclen dithiocarbamate Ag NPs

393

8.0 and 4.0

Optunal

5 3 1026 1023 M

1027 M

[16]

420 400

38 6 5 6 nm

Dimethoate Tricyclazole

10 100 3 1028 M 1.0 100 μM

10 3 1029 1.8 3 1027 M

[17] [18]

396

10.0

397 394

5.8 16

Thiram Paraquat Carbendazim Mancozeb

10.0 20.0 μM 50.0 250 μM 10 100 μM 5 3 1025 3 3 1024 M

2.81 3 1026 M 7.21 3 1026 M 1.04 μM 21.1 3 1026 M

[19] [19] [20] [21]

400

8.1 6 2 nm

Triazophos

0.5 500 μM

0.08 μM

[22]

399

9.5

Glyphosate

0.1 1.2 μM

17.1 nM

[23]

Prothioconazole Triazophos 6-Benzylaminopurine Thiophanate-methyl Dipterex Endrin Diazinon

0.01 0.4 μg mL21 0.1 280 μM 4 26 μM 2.0 100 μM 0.25 37.5 ng mL21 0.05 5.00 μg mL21 10 600 ng mL21

1.7 ng mL21 5.0 nM 0.2 μM 0.1 μM 0.18 ng mL21 0.015 μg mL21 3.5 ng mL21

[25] [26] [27] [28] [29] [30] [31]

4-Aminobenzenethiol Ag NPs Dopamine dithiocarbamate Ag NPs 3-MPA and guanidine acetic acid Ag NPs 2-Mercapto-5nitrobenzimidazole Mg21 Ag NPs Unmodified-Ag NPs Cit-Ag NPs TGA Ag NPs Cit-Ag NPs Cit-Ag NPs Sucrose-Ag NPs Ag NPs

395 394 397 394 396 400 395

8.0

4.2 6 0.8 nm 15.4 6 1.5 nm

Cit, Citrate; MPA, mercaptopropinonic acid; SPR, surface plasmon resonance; TGA, thioglycolic acid.

422

Handbook of Nanomaterials in Analytical Chemistry

been described the colorimetric sensing ability of Au NPs for the selective and sensitive recognition of wide variety of chemical species including pesticides. In this section, we summarize the analytical applications of functional Au NPs for the selective and sensitive colorimetric detection of pesticides in water and food samples. For example, lipoic acid (LA) was functionalized onto the surfaces of Au NPs for label-free colorimetric recognition of organophosphate nerve agents and pesticide via catalytic reaction of AChE [32]. The authors noticed that the hydrolyzed products (cationic TCh) of AChE was significantly induced the aggregation of LA Au NPs, which results a distinct color change from red to steel-blue. The spectroscopic data reveal that cationic TCh was effectively replaced by the LA due to the formation of covalent bond between mercapto group of TCh and Au NPs surfaces. As a result, the well-dispersed LA Au NPs were aggregated by replacing the LA with TCh, resulting a drastic decrease in SPR peak of LA Au NPs at 523 nm and appearance of a new SPR peak at 625 nm, which confirms the aggregation of Au NPs. The developed method was successfully applied to detect paraoxon in spiked apple juice. Similarly, Fu’s group developed a simple colorimetric probe for the detection of paraoxon via Cu(I)-catalyzed click chemistry with azide- and terminal alkyne-Au NPs [33]. In this work, the authors found that Cu1 ion acts as a catalyst for cycloaddition reaction between azide and terminal alkyne groups on surfaces of Au NPs, which results to form CuO NPs by enzymatic reaction. This sensing mechanism is based on the Cu1 ion catalyzed click chemistry. The author observed that the CuO NPs play key role as the catalyst for the inducement of Au NPs aggregation by AChE ATCl system and acetic acid (Fig. 16.3). These results revealed that Cu1 ion acted as intermediate element for the colorimetric detection of paraoxon via click chemistry. The developed proof was successfully used for onsite monitoring of paraoxon via colorimetric readout assay, which can be observed with naked eye without the aid of sophisticated instruments. Further, similar metal ion based click chemistry approach was developed for the detection of organophosphorous pesticides via the dissolution of Au NPs in Au31 ioncetyltrimethylammonium bromide (CTAB) [34]. The developed method exhibited good accuracy and precision for the detection of organophosphrous pesticides in water samples, suggesting the developed method is well agreed with the liquidchromatography mass-spectrometric method. Multicolor nanoprobe was developed for the detection of dichlorvos and demeton pesticides via the formation of gold nanorods (Au NRs) via enzymatic etching process [35]. The authors noticed that the acetylcholine was catalyzed to form hydrogen peroxide (H2O2) in the presence of AChE and choline oxidase. This results to form Au NRs along with the formation of color with different color variations. Dichlorvos and demeton pesticides were quantitatively estimated based on the LSPR band shift of Au NRs, which exhibits linear relationship with the concentration of organophosphorous pesticides. Remarkably, this method exhibited lower LOD, which were much lower than that of the maximum permissible limits recommended by the US Department of Agriculture and European Union pesticide regulations. A simple colormetric method was developed for the detection of mathamidophos in vegetables by using Cit-Au NPs as a recognition element [36]. This assay was

Surface-modified metal nanoparticles for recognition of toxic organic molecules

423

Figure 16.3 Colorimetric assay of organophosphorus pesticides using Cu(II)-catalyzed click chemistry (Au NPs: OPs: organophosphate pesticides; ATCl: acetylthiocholine; AChE: acetylcholineesterase; CuO NPs). Source: Reprinted from G. Fu, W. Chen, X. Yue, X. Jiang, Highly sensitive colorimetric detection of organophosphate pesticides using copper catalyzed click chemistry, Talanta 103 (2013) 110 115 with permission.

based on the hydrolysis of ATCh that yields TCh by the enzymatic catalysis of AChE. As a result, dispersed Cit-Au NPs were aggregated, which accompanies by color change from cherry red to purple and then gray. This method exhibited good selectivity and sensitivity for assaying of mathamidophos in vegetables with good accuracy and precision. Similarly, a novel Au NPs based colorimetric assay was developed for the detection of dichlorvos in water and food samples [37]. In this work, Au NPs were synthesized by one-step reaction using ascorbic acid (AA) as a reducing and capping agent. The sensing mechanism is based on the aggregation of AA Au NPs induced by dichlorvos through hydrogen-bonding. Rastegarzadeh and Abdali developed a colormetric method for the detection of thiram in water and plant seed samples by using AA CTAB Au NPs as a colorimetric probe [38]. In this work, the authors evaluated various parameters such as effect of pH, effect of time, and effects of AA and CTAB concentrations for effective colorimetric recognition of thiram. Under the optimal conditions, calibration graph was plotted between absorption ratio and the concentration of thiram (2.0 3 1027 1.0 3 1025 M), exhibiting good linearity with regression equation ΔA 5 2.550 3 104 C (thiram, M) 1 0.038 and R2 5 0.9990. The authors achieved impressive detection limit of 1.7 3 1027 M for thiram in water samples. Xu’s group described the colorimetric recognition ability of Cit-Au NPs for assaying of acetamiprid in vegetable samples [39]. In this work, the authors evaluated the analytical performance of two different sizes, that is, 22.0 6 1.0 and 15.0 6 1.0 nm, suggesting the

424

Handbook of Nanomaterials in Analytical Chemistry

larger size Cit-Au NPs (22.0 6 1.0 nm) exhibited superior sensitivity than the smaller size (15.0 6 1.0 nm) of Cit-Au NPs. The authors noticed that the Cit-Au NPs were greatly aggregated upon the addition of acetamiprid due to the strong affinity of CN group of acetamiprid toward Cit-Au NPs via van der Waals attraction. The developed method was successfully applied to detect acetamiprid in green vegetables, eggplant, and cucumber, exhibiting good recovery ranges from 93.1% to 102.0% with low relative standard deviation (RSD) values. The SPR-based biosensor was fabricated by immobilizing antiatrazine onto the surfaces of Au NPs via carbodiimide cross-linker chemistry [40]. The authors investigated that the SPR biosensing ability of different diameters (17, 24, and 30 nm) of Au NPs for colorimetric recognition of atrazine. It was observed that the size of 30 nm Au NPs exhibited the SPR signal intensity 7.17 times higher than that of the sizes of 24 and 17 nm Au NPs, confirming the size of Au NPs play key role in colorimetric recognition of pesticides. This method exhibited impressive recovery ranges from 87.2% to 94.2%, demonstrating the SPR-based biosensor was successfully used for the detection of atrazine in maize samples. A facile and rapid simultaneous colorimetric method was developed for the detection of six pesticides (acephate, profenofos, phenthoate, acetamiprid, chlorothalonil, and cartap) in water and vegetables via ligand exchange reactions on the surfaces of Cit-Au NPs [41]. The sensing mechanism is based on the ligand exchange reactions between Cit molecules on the surface of Au NPs and pesticides, since pesticides have active functional groups (amino, thio, cyano, and carbonyl), which show strong ability to replace the Cit molecules on the surfaces of Au NPs via the formation of Au-S and Au-N bonding. The authors have investigated the morphology of Cit-Au NPs with addition of six pesticides by TEM and dynamic light scattering, revealing the average diameter of Cit-Au NPs (13.5 6 2.5 nm) was figuratively increased to 431, 372, 291, 395, 490, and 322 nm for phenthoate, acephate, acetamiprid, profenofos, cartap, and chlorothalonil, respectively, which confirm the aggregation Cit-Au NPs induced by six pesticides. Furthermore, the authors also investigated the effect of pH on colorimetric sensing of six pesticides using sodium acetate buffer pH from 2.0 to 12.0. It was noticed that high degree of aggregations were observed at pH 4.0 for phenthoate, acephate, and profenofos, and at pH 6 for chlorothalonil and acetamiprid, and at neutral pH for cartap. These studies revealed that pH of the solution plays key role for simultaneous colorimetric recognition of six pesticides without aid of chromatographic techniques. Recently, our group explored the role of surface chemistry on the surfaces of Au NPs for tuning of their colorimetric sensing applications for the detection of various pesticides in water and food samples. Briefly, various dithiocarbamates such as 4-hydroxy-6-methyl-3-nitro-2-pyridone-dithiocarbamate (HMNP-DTC) [42], ractopamine-dithiocarbamate (RAC-DTC) [43], nitro and hydroxy benzylindoledithiocarbamate (NBI- and HBI-DTC) [44], dithiocarbamate-p-tertbutylcalix[4] arene (DTC-PTBCA) [45], and p-nitroaniline dithiocarbamate (p-NA-DTC) [46] were functionalized on the surfaces of Au NPs for colorimetric detection of various pesticides (diafenthiuron, pendimethalin, terbufos, thiacloprid, metsulfuron-methyl, and quinalphos) in water and food samples. It was observed that HMNP-DTC-Au

Surface-modified metal nanoparticles for recognition of toxic organic molecules

425

NPs were selectively detected diafenthiuron, whereas Cit-Au NPs did not show any significant color change, which confirms that HMNP-DTC plays a key role in colorimetric recognition of diafenthiuron [42]. The aggregation of HMNP-DTC-Au NPs induced by diafenthiuron is due to electron donor acceptor interactions between HMNP-DTC-Au NPs and diafenthiuron. As a result, the distance between diafenthiuron-HMNP-DTC-Au NPs was drastically reduced due to the hydrogenbonding, which leads to minimize interparticle distance between HMNP-DTC-Au NPs via π π interaction. Similarly, pendimethalin herbicide was quantified by using RAC-DTC-Au NPs as a probe [43]. The RAC-DTC-Au NPs were greatly aggregated by the addition of pendimethalin due to various interactions (π π, donor acceptor, hydrogenbonding, and van der Waals), which results a change in color from red to blue. To establish RAC-DTC-Au NPs as promising probe, the degree of aggregation of RAC-DTC-Au NPs induced by pendimethalin was investigated at phosphatebuffered saline (PBS) pH in range of 2.0 12. It was noticed that the high degree of aggregation was observed only at PBS pH 9.0, which reveals that PBS pH 9.0 is optimum pH for the detection of pendimethalin. The absorption ratio A650/A522 was progressively increased with increasing concentration of pendimethalin (5.0 500 μM), achieving lower detection limit, that is, 2.2 3 1027 M, which is closely matching with the maximum permissible limits of pendimethalin (0.05 ppm 5 1.7 3 1027 M) by European Commission. The colorimetric sensing application of Au NPs was tuned with NBI- and HBI-DTC derivatives for assaying of terbufos and thiacloprid [44]. The authors noticed that the SPR peaks of NBIand HBI-DTC-Au NPs were shifted to 630 and 625 nm, accompanying color change from red to blue. The functionalized Au NPs were specifically aggregated only with the addition of terbufos and thiacloprid, signifying the decrease of interparticle distance of functionalized Au NPs through π π and donor acceptor interactions (Fig. 16.4). The intensity of new SPR peaks was progressively increased with increasing concentrations of terbufos (0.5 50 μM) and of thiacloprid (5.0 500 μM) with LODs of 7.3 3 1028 and 6.0 3 1027 M. Importantly, this method exhibited good recovery ranges from 97.16% to 99.31%, suggesting the present method can be successfully used for the simultaneous detection of terbufos and thiacloprid in real samples. Furthermore, Au NPs were functionalized with DTC-PTBCA for distinctive colorimetric recognition of metsulfuron-methyl in water and food samples [45]. The sensing ability is based on the aggregation of DTC-PTBCA-Au NPs induced by metsulfuron-methyl. The calixarenes contain phenol units, which are linked via methylene bridges. Importantly, calixarenes exhibit as a “calix crater,” allowing to form effective noncovalent interactions with metsulfuron-methyl (Fig. 16.5), which results a drastic red-shift in the SPR peak (524 572 nm). The higher absorption ratio (A524/A572) was observed at PBS pH 7.0, confirming the metsulfuron-methyl was highly induced the aggregation of DTC-PTBCA-Au NPs through host guest (noncovalent) interactions. The red-shift was observed only by the addition of metsulfuron-methyl even in the presence of pesticides, conforming its selectivity toward metsulfuron-methyl. This method was successfully applied to assay

Figure 16.4 Colorimetric sensing phenomenon for visual detection of terbufos and thiacloprid using NBI- and HBI-DTC-Au NPs as probes. NBI- and HBI-DTC, nitro and hydroxy benzylindole-dithiocarbamate; NPs, nanoparticles. Source: Reprinted from S.K. Kailasa, J.V. Rohit, Tuning of gold nanoparticles analytical applications with nitro and hydroxy benzylindoledithiocarbamates for simple and selective detection of terbufos and thiacloprid insecticides in environmental samples, Colloids Surf. A 515 (2017) 50 61 with permission.

Surface-modified metal nanoparticles for recognition of toxic organic molecules

427

Figure 16.5 Aggregation of DTC-PTBCA-Au NPs induced by metsulfuron-methyl via host guest (noncovalent) interaction. DTC-PTBCA, Dithiocarbamate-p-tertbutylcalix[4] arene; NPs, nanoparticles. Source: Reprinted from J.V. Rohit, R.K. Singhal, S.K. Kailasa, Dithiocarbamate-calix[4] arene functionalized gold nanoparticles as a selective and sensitive colorimetric probe for assay of metsulfuron-methyl herbicide via non-covalent interactions, Sens. Actuators, B: Chem. 237 (2016) 1044 1055 with permission.

metsulfuron-methyl in water and food samples. Similarly p-NA-DTC molecules were effectively assembled on the surfaces of Au NPs for colorimetric assay of quinalphos in food and water samples [46]. The intensity of new SPR peak at 694 nm was progressively increased with increasing concentration of quinalphos. It was noticed that the absorption ratio (A694/A522) was remarkably increased at ammonium acetate pH 5.0 because of high degree of aggregation via multiple interactions (π π and electron donor acceptor interactions). This method was successfully applied to analyze quinalphos in water, tomato, rice, and wheat samples. This method exhibited good recoveries in the range of 97.5% 99.2% with relative standard deviation (RSD) values ,3.0%, indicating the developed method shows good accuracy and precision for the analysis of quinalphos in real samples. Bala’s group developed a facile and rapid analytical method for the assay of ethyl parathion using L-cysteine functionalized Au NPs as a probe [47]. This assay is based on the color change from red to blue due to the hydrolysis of ATCh by AChE. The authors noticed that the product of TCh is significantly suppressed by the addition of ethyl parathion, which results there is no color change. The authors achieved impressive detection limit of 0.081 ng mL21. This method was effectively applied to detect ethyl parathion in real samples. The same group demonstrated the use of polydiallyldimethylammonium chloride (PDDA) and aptamer on the surfaces of Au NPs for colorimetric assay of malathion in water and food samples [48]. The authors noticed that the selective aggregation of Au NPs was observe only with the addition of malathion, signifying the formation of complex between malathion and aptamer, which allows to form free PDDA that accompanies the aggregation of Au

Table 16.2 Functional Au nanoparticles (NPs) as probes for colorimetric recognition of pesticides. Functional Au NPs

SPR peak (nm)

Size (nm)

Analyte

Linear range

Limit of detection

Reference

LA Au NPs Azide- and terminal alkyne-Au NPs Au31 CTAB CTAB Au NRs

523 530

12

Paraoxon-ethyl Paraoxon

4.52 3 104 4.95 3 105 pM 10216 10214 g L21

4.52 3 104 pM 1026 g L21

[32] [33]

524 639, 693, and 807 522 525 527 520

13

Parathion Dichlorvos and demeton Mathamidophos Dichlorvos Thiram Acetamiprid

15 65 ppb 0.01 50 μg L21(dichlorvos) 1.0 500 μg L21 (demeton) 0.02 1.42 μg mL21 100 1000 μM 2.0 3 1027 2 1.0 3 1025 M 6.6 3 1027 6.6 3 1025 M

0.7 ppb (2.4 nM) 8.1 3 1023 μg L21(dichlorvos) 0.32 μg L21 (demeton) 1.40 ng mL21 42.94 μM 1.7 3 1027 M 4.4 3 1028 M

[34] [35]

Atrazine

1.0 15.6 ng mL21

1.0 ng mL21

[40]

Acephate Phenthoate Profenofos Acetamiprid Chlorothalonil Cartap Diafenthiuron Pendimethalin Terbufos Thiacloprid Metsulfuronmethyl Quinalphos Ethyl parathion Malathion

10 900 μM 0.01 1.50 1.0 200 0.001 0.15 1.0 1000 0.05 1.50 0.05 10 μM 5.0 500 μM 1.0 100 μM 100 1000 μM 1.0 50 μM

3.46 3 1027 M 3.0 3 1029 6.0 3 1027 6.24 3 10210 3.75 3 1027 1.7 3 1028 7.1 nM 0.22 μM 7.3 3 1028 M 6.0 3 1027 M 1.9 3 1027 M

[41]

10 1000 μM 0.02 0.20 ng mL21 0.5 1000 pM

3.21 μM 0.081 ng mL21 0.06 pM

[46] [47] [48]

Citrate-Au NPs Ascorbic acid Au NPs AA CTAB Au NPs Citrate-Au NPs

Citrate-Au NPs

518, 524, and 529 525

20 14.5 10 15.0 6 1.0 17, 24 and 3,0 ,16.0

HMNP-DTC-Au NPs RAC-DTC-Au NPs NBI-DTC-Au NPs HBI-DTC-Au NPs DTC-PTBCA-Au NPs

522 522 523 522 524

17 18 19 18 15

p-NA-DTC-Au NPs L-Cysteine-Au NPs PDDA-Au NPs

522 520 518

17 13

Antiatrazine-Au NPs

[36] [37] [38] [39]

[42] [43] [44] [44] [45]

AA, Ascorbic acid; CTAB, cetyltrimethylammonium bromide; DTC-PTBCA, dithiocarbamate-p-tertbutylcalix[4]arene; HBI-DTC, hydroxy benzylindole-dithiocarbamate; HMNP-DTC, 4-hydroxy-6-methyl-3-nitro-2pyridone-dithiocarbamate; LA, lipoic acid; NBI-DTC, nitrobenzylindole-dithiocarbamate; PDDA, polydiallyldimethylammonium chloride; RAC-DTC, ractopamine-dithiocarbamate; SPR, surface plasmon resonance.

Surface-modified metal nanoparticles for recognition of toxic organic molecules

429

NPs. This method exhibited good linearity in the range of picomolar concentration with detection limit of 0.06 pM. This method was successfully applied to rapid screening of malathion in real samples. Table 16.2 summarizes the remarkable features of Au NPs based colorimetric sensing platforms for assaying of various pesticides.

16.4

Summary

Ultrasensitive assay of pesticides in various sample matrices has shown considerable interest in agriculture and food sciences. In this chapter, we summarized the analytical features of functional Ag and Au NPs for colorimetric assay of various pesticides. It was noticed that the colorimetric sensing ability of Ag and Au NPs was tuned by functionalizing NPs with wide variety of organic ligands. The functionalized NPs exhibited specific recognition ability due to the specific interactions with the target pesticides, resulting the aggregation of NPs, accompanying by color change that can be noticed with naked eye. Importantly, there is a remarkable shift in the SPR peak, and the absorption ratio is linear with increasing concentration of pesticides. These methods exhibited lower detection limits with good accuracy and precision. The analytical performance of functional Ag and Au NPs based colormetric approaches is comparable with the sophisticated instruments. The analytical features of Ag and Au NPs based colorimetric approaches revealed that they provided simple and portable analytical platforms for on-site screening of pesticides without aid of sophisticated instruments and sample preparations.

Acknowledgment SKK acknowledges the Department of Science and Technology, Government of India (EMR/ 2016/002621/IPC) for financial support.

References [1] M. Li, H. Gou, I. Al-Ogaidi, N. Wu, Nanostructured sensors for detection of heavy metals: a review, ACS Sustain. Chem. Eng. 1 (2013) 713 723. [2] S.K. Kailasa, H.-F. Wu, One-pot synthesis of dopamine dithiocarbamate functionalized gold nanoparticles for quantitative analysis of small molecules and phosphopeptides in SALDI-and MALDI-MS, Analyst 137 (2012) 1629 1638. [3] C.M. Hussain, Nanomaterials in Chromatography: Current Trends in Chromatographic Research Technology and Techniques, Elsevier, 2018. [4] C.M. Hussain, Handbook of Nanomaterials for Industrial Applications, Elsevier, 2018. [5] S.K. Ghosh, T. Pal, Interparticle coupling effect on the surface plasmon resonance of gold nanoparticles: from theory to applications, Chem. Rev. 107 (2007) 4797 4862.

430

Handbook of Nanomaterials in Analytical Chemistry

[6] K. Saha, S.S. Agasti, C. Kim, X. Li, V.M. Rotello, Gold nanoparticles in chemical and biological sensing, Chem. Rev. 112 (2012) 2739 2779. [7] K.Y. Goud, S.K. Kailasa, V. Kumar, Y.F. Tsang, S.E. Lee, K.V. Gobi, et al., Progress on nanostructured electrochemical sensors and their recognition elements for detection of mycotoxins: a review, Biosens. Bioelectron. 121 (2018) 205 222. [8] S.K. Kailasa, J.R. Koduru, M.L. Desai, T.J. Park, R.K. Singhal, H. Basu, Recent progress on surface chemistry of plasmonic metal nanoparticles for colorimetric assay of drugs in pharmaceutical and biological samples, TrAC, Trends Anal. Chem. 105 (2018) 106 120. [9] A. Azzouz, S.K. Kailasa, S.S. Lee, A.J. Rascon, E. Bellesteros, M. Zhang, et al., Review of nanomaterials as sorbents in solid-phase extraction for environmental samples, TrAC, Trends Anal. Chem. 108 (2018) 347 369. [10] J.R. Koduru, S.K. Kailasa, J.R. Bhamore, K.H. Kim, T. Dutta, K. Vellingiri, Phytochemical-assisted synthetic approaches for silver nanoparticles antimicrobial applications: a review, Adv. Colloid Interface Sci. 256 (2018) 326 339. [11] S.K. Kailasa, H.F. Wu, Nanomaterial-based miniaturized extraction and preconcentration techniques coupled to matrix-assisted laser desorption/ionization mass spectrometry for assaying biomolecules, TrAC, Trends Anal. Chem. 65 (2015) 54 72. [12] S.K. Kailasa, H.F. Wu, Recent developments in nanoparticle-based MALDI mass spectrometric analysis of phosphoproteomes, Microchim. Acta 181 (2014) 853 864. [13] S.K. Kailasa, V.N. Mehta, H.F. Wu, Recent developments of liquid-phase microextraction techniques directly combined with ESI- and MALDI-mass spectrometric techniques for organic and biomolecule assays, RSC Adv. 4 (2014) 16188 16205. [14] A. Samsidar, S. Siddiquee, S. Md Shaarani, A review of extraction, analytical and advanced methods for determination of pesticides in environment and foodstuffs, Trends Food Sci. Technol. 71 (2018) 188 201. [15] S. Grimalt, P. Dehouck, Review of analytical methods for the determination of pesticide residues in grapes, J. Chromatogr. A 1433 (2016) 1 23. [16] D. Xiong, H. Li, Colorimetric detection of pesticides based on calixarene modified silver nanoparticles in water, Nanotechnology 19 (2008) 465502 (6pp). [17] S.K. Menon, N.R. Modi, A. Pandya, A. Lodha, Ultrasensitive and specific detection of dimethoate using a p-sulphonato-calix[4]resorcinarene functionalized silver nanoprobe in aqueous solution, RSC Adv. 3 (2013) 10623 10627. [18] J.V. Rohit, S.K. Kailasa, 5-Sulfo anthranilic acid dithiocarbamate functionalized silver nanoparticles as a colorimetric probe for the simple and selective detection of tricyclazole fungicide in rice samples, Anal. Methods 6 (2014) 5934 5941. [19] J.V. Rohit, S.K. Kailasa, Cyclen dithiocarbamate-functionalized silver nanoparticles as a probe for colorimetric sensing of thiram and paraquat pesticides via host guest chemistry, J. Nanopart. Res. 16 (2014) 1 16. [20] G.M. Patel, J.V. Rohit, R.K. Singhal, S.K. Kailasa, Recognition of carbendazim fungicide in environmental samples by using 4-aminobenzenethiol functionalized silver nanoparticles as a colorimetric sensor, Sens. Actuators, B: Chem. 206 (2015) 684 691. [21] J.V. Rohit, J.N. Solanki, S.K. Kailasa, Surface modification of silver nanoparticles with dopamine dithiocarbamate for selective colorimetric sensing of mancozeb in environmental samples, Sens. Actuators, B: Chem. 200 (2014) 219 226. [22] J.R. Bhamore, P. Ganguly, S.K. Kailasa, Molecular assembly of 3-mercaptopropinonic acid and guanidine acetic acid on silver nanoparticles for selective colorimetric detection of triazophos in water and food samples, Sens. Actuators, B: Chem. 233 (2016) 486 495.

Surface-modified metal nanoparticles for recognition of toxic organic molecules

431

[23] K.A. Rawat, R.P. Majithiya, J.V. Rohit, H. Basu, R.K. Singhal, S.K. Kailasa, Mg21 ion as a tuner for colorimetric sensing of glyphosate with improved sensitivity via the aggregation of 2-mercapto-5-nitrobenzimidazole capped silver nanoparticles, RSC Adv. 6 (2016) 47741 47752. [24] http://www.fao.org/fao-who-codexalimentarius/codex-texts/dbs/pestres/pesticides/en/. [25] Z.J.-N. Ivrigh, N. Fahimi-Kashani, M.R. Hormozi-Nezhad, Aggregation-based colorimetric sensor for determination of prothioconazole fungicide using colloidal silver nanoparticles (AgNPs), Spectrochim. Acta, A 187 (2017) 143 148. [26] S. Ma, J. He, M. Guo, X. Sun, M. Zheng, Y. Wang, Ultrasensitive colorimetric detection of triazophos based on the aggregation of silver nanoparticles, Colloids Surf. A 538 (2018) 343 349. [27] M. Zheng, J. He, Y. Wang, C. Wang, S. Ma, X. Sun, Colorimetric recognition of 6benzylaminopurine in environmental samples by using thioglycolic acid functionalized silver nanoparticles, Spectrochim. Acta, A 192 (2018) 27 33. [28] M. Zheng, Y. Wang, C. Wang, W. Wei, S. Ma, X. Sun, et al., Silver nanoparticlesbased colorimetric array for the detection of thiophanate-methyl, Spectrochim. Acta, A 198 (2018) 315 321. [29] J. Sun, L. Guo, Y. Bao, J. Xie, A simple, label-free AuNPs-based colorimetric ultrasensitive detection of nerve agents and highly toxic organophosphate pesticide, Biosens. Bioelectron. 28 (2011) 152 157. [30] K. Shrivas, N. Nirmalkar, A. Ghosale, S.S. Thakura, Application of silver nanoparticles for a highly selective colorimetric assay of endrin in water and food samples based on stereoselective endo-recognition, RSC Adv. 6 (2016) 29855 29862. [31] K. Shrivas, S. Sahu, B. Sahu, R. Kurrey, T.K. Patle, T. Kant, et al., Silver nanoparticles for selective detection of phosphorus pesticide containing π-conjugated pyrimidine nitrogen and sulfur moieties through non-covalent interactions, J. Mol. Liq. 275 (2019) 297 303. [32] Z. Lia, Y. Wang, Y. Ni, S. Kokot, Unmodified silver nanoparticles for rapid analysis of the organophosphorus pesticide, dipterex, often found in different waters, Sens. Actuators, B: Chem. 193 (2014) 205 211. [33] G. Fu, W. Chen, X. Yue, X. Jiang, Highly sensitive colorimetric detection of organophosphate pesticides using copper catalyzed click chemistry, Talanta 103 (2013) 110 115. [34] S. Wu, D. Li, J. Wang, Y. Zhao, S. Dong, X. Wang, Gold nanoparticles dissolution based colorimetric method for highly sensitive detection of organophosphate pesticides, Sens. Actuators, B: Chem. 238 (2017) 427 433. [35] Y. Liu, B. Lv, A. Liu, G. Liang, L. Yin, Y. Pu, et al., Multicolor sensor for organophosphorus pesticides determination based on the bi-enzyme catalytic etching of gold nanorods, Sens. Actuators, B: Chem. 265 (2018) 675 681. [36] H. Li, J. Guo, H. Ping, L. Liu, M. Zhang, F. Guan, et al., Visual detection of organophosphorus pesticides represented by mathamidophos using Au nanoparticles as colorimetric probe, Talanta 87 (2011) 93 99. [37] S.L. D’souza, R.K. Pati, S.K. Kailasa, Ascorbic acid functionalized gold nanoparticles as a probe for colorimetric and visual read-out determination of dichlorvos in environmental samples, Anal. Methods 6 (2014) 9007 9014. [38] S. Rastegarzadeh, Sh Abdali, Colorimetric determination of thiram based on formation of gold nanoparticles using ascorbic acid, Talanta 104 (2013) 22 26. [39] Q. Xu, S. Du, J. Gen-di, H. Li, X.Y. Hu, Determination of acetamiprid by a colorimetric method based on the aggregation of gold nanoparticles, Microchim. Acta 173 (2011) 323 329.

432

Handbook of Nanomaterials in Analytical Chemistry

[40] X. Liu, Y. Yang, L. Mao, Z. Li, C. Zhou, X. Liu, et al., SPR quantitative analysis of direct detection of atrazine traces on Au-nanoparticles: nanoparticles size effect, Sens. Actuators, B: Chem. 218 (2015) 1 7. [41] K. Rana, J.R. Bhamore, J.V. Rohit, T.-J. Park, S.K. Kailasa, Ligand exchange reactions on citrate-gold nanoparticles for a parallel colorimetric assay of six pesticides, New J. Chem. 42 (2018) 9080 9090. [42] S.K. Kailasa, J.V. Rohit, Multi-functional groups of dithiocarbamate derivative assembly on gold nanoparticles for competitive detection of diafenthiuron, Sens. Actuators, B: Chem. 244 (2017) 796 805. [43] J.V. Rohit, S.K. Kailasa, Simple and selective detection of pendimethalin herbicide in water and food samples based on the aggregation of ractopamine-dithiocarbamate functionalized gold nanoparticles, Sens. Actuators, B: Chem. 245 (2017) 541 550. [44] S.K. Kailasa, J.V. Rohit, Tuning of gold nanoparticles analytical applications with nitro and hydroxy benzylindole-dithiocarbamates for simple and selective detection of terbufos and thiacloprid insecticides in environmental samples, Colloids Surf. A 515 (2017) 50 61. [45] J.V. Rohit, R.K. Singhal, S.K. Kailasa, Dithiocarbamate-calix[4]arene functionalized gold nanoparticles as a selective and sensitive colorimetric probe for assay of metsulfuron-methyl herbicide via non-covalent interactions, Sens. Actuators, B: Chem. 237 (2016) 1044 1055. [46] J.V. Rohit, H. Basu, R.K. Singhal, S.K. Kailasa, Development of p-nitroaniline dithiocarbamate capped gold nanoparticles-based microvolume UV vis spectrometric method for facile and selective detection of quinalphos insecticide in environmental samples, Sens. Actuators, B: Chem. 237 (2016) 826 835. [47] R. Bala, R.K. Sharma, N. Wangoo, Highly sensitive colorimetric detection of ethyl parathion using gold nanoprobes, Sens. Actuators, B: Chem. 210 (2015) 425 430. [48] R. Bala, M. Kumar, K. Bansal, R.K. Sharma, N. Wangoo, Ultrasensitive aptamer biosensor for malathion detection based on cationic polymer and gold nanoparticles, Biosens. Bioelectron. 85 (2016) 445 449.

Safety risk, ELSI (ethical, legal, social issues), and economics of nanomaterials

17

Gustavo Marques da Costa1 and Chaudhery Mustansar Hussain2 1 Technology and Environmental Management, Feevale University, Novo Hamburgo, Brazil, 2Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, NJ, United States

17.1

Introduction

The need for new technologies using existing materials was the beginning of a revolution through which nanoscience and nanotechnology emerged. The study of raw materials, which are in the range of nanometers, gained prominence in the late 20th century, leading to the emergence of nanotechnology. The prefix “nano” is derived from the Greek “dwarf,” where 1 nm equals 1 billionth of a meter. Metal nanoparticles (gold, silver, platinum, iron), semiconductor nanoparticles (zinc oxide, titanium dioxide), and carbon nanotubes, among others, are examples in nanotechnology. Due to their physicochemical properties and wide application potential, they offer diversified innovation opportunities [1,2]. The European Union’s (EU’s) Scientific Committee on Consumer Products classified the use of nanoparticles into labile and insoluble. The labile nanoparticles are easily destroyed by predictable physicochemical conditions in the case of liposomes, lipid, and biodegradable nanoparticles, while the insoluble particles such as carbon nanotubes and metal nanoparticles are unable to destructure in biological means. In this context, we have nanoparticles, which have unusual physicochemical properties, such as reduced size, chemical composition, electronic properties, and aggregation form. In the area of toxicology the term metabolism refers to the chemical modification of a xenobiotic. However, some nanomaterials are transported through cell membranes, especially in mitochondria. Besides, some characteristics such as chemical structure, size, and dose of the nanoparticles are also determinant factors in the toxicity of different nanostructured systems. In addition to carbon nanotubes and nanoparticles, there are also nanocapsules of titanium dioxide (TiO2), made up of a white, odorless powder capable of absorbing and reflecting light and which is used as a white pigment in a large quantity of products, such as paints, paper, plastic, ceramics, cosmetics, food colorants, drugs, and electronic components. Currently, TiO2 nanoparticles are used because of their high stability,

Handbook of Nanomaterials in Analytical Chemistry. DOI: https://doi.org/10.1016/B978-0-12-816699-4.00017-7 Copyright © 2020 Elsevier Inc. All rights reserved.

436

Handbook of Nanomaterials in Analytical Chemistry

as well as their use as a protective film against corrosion. Also, the superparamagnetic iron oxide nanoparticles, also called magnetite nanoparticles or maghemite, become superparamagnetic at room temperature which confers on them numerous areas of application, such as tissue repair, cell marking, diagnosis, and treatment of cancer. There are many products that have nanotechnology in their formulation and have grown by an average of 20% over the last few years according to the inventory of consumer products with nanotech components available on the world market [3], and it can be used in the food industry, cosmetics, pesticides, clothing, digital cameras, automotive paints, among others. According to Statnano [4], the number of products with nanoparticles is 6059 in 825 companies in 47 countries, mainly in the cosmetics, construction, and textile industries, with the United States being the country with the largest quantity and variety of products containing nanotechnology. In addition, according to the report by BBC Research, the global nanotechnology market has projected a 2019 increase of $64.2 billion, with annual growth rates of 19.8%, impacting on all sectors of the economy, such as biomedical, electronic, energy, environmental, and pharmaceutical [5]. According to the Nanodatabase [6], most products with nanomaterials have increased over time (Fig. 17.1), with health and fitness corresponding to 1845, while only one-sixth of the products falls into the category of home and garden (555). From 1845 health and fitness products, just over 700 products are personal care products, about 400 are clothing and, approximately, 400 other are sporting goods. Nanodatabase states that silver is the nanomaterial reported to be used in most products (Fig. 17.2). Therefore nanotechnology is everywhere in our clothing, cars, computers and monitors, cosmetics and medicines, adding new functionalities, intelligence,

Product vs year 3500

Number of products

3000

3035

3036

2017

2018 2019 Highcharts.com

3036

2388

2500

2271

2000 1500

1421 1208

1213

2012

2013

1000 500 0

2014

2015

2016 Year

Figure 17.1 Number of products using nanomaterials in the period from 2012 to 2019. Source: http://nanodb.dk/en/analysis/consumer-products/#chartHashsection, reproduced with permission from The Nanodatabase.

Safety risk, ELSI (ethical, legal, social issues), and economics of nanomaterials

437

Product vs nanomaterial 2750 2500 2250

Number of products

2012 2013 2014 2015 2016 2017 2018 2019

2000 1750

191 195 214 330

1500 1250

344

1000

378

750

31

500

378

250

378

123

Silver

Titanium dioxide Nanomaterial

0

102

28 59 64 Carbon nanotubes Highcharts.com

Figure 17.2 Number of products and type of nanomaterial in the period from 2012 to 2019. Source: http://nanodb.dk/en/analysis/consumer-products/#chartHashsection, reproduced with permission from The Nanodatabase.

integrations, portability, and networking capability in many new products with high market potential [7]. However, in recent years, there has been a significant shift in research on human potential and environmental exposures of consumer products based on nanotechnology. Thus this chapter aims to describe the safety risk, ELSI (ethical, legal, social issues), and the economics of nanomaterials.

17.2

Nanomaterials and environment

The nanoparticles can influence the environment by natural sources, such as volcanic emissions, or anthropogenic sources, such as refining, tobacco smoke, engines, food processing. However, industrial processes or activities involving the burning of fossil fuels generate a significant amount of particulate material (PM2.5), and they have been identified in several epidemiological studies as causing various adverse health effects [8 10]. In this context, different types of nanomaterials, such as carbon nanotubes, metals (oxides), and biological nanomarkers, are being discovered every day because more efficient, light, adequate, and mainly low-cost final products are feasible. However, the toxicity of nanoparticles lies mainly in the fact that they have never been produced and used in commercial products on such a large scale as at present, and therefore the risk of reaching different environmental compartments (atmosphere, water, and soil) becomes significant [11,12]. However, it is important to mention that the presence of nanomaterials in the environment does not mean that there will always be the manifestation and observation of adverse or toxic effects associated with them, since the expression of these effects depends on the characteristics of the exposure and its behavior in the environment [13].

438

Handbook of Nanomaterials in Analytical Chemistry

Moreover, there is the application of nanomaterials in the process of environmental decontamination, and this is due to the high chemical reactivity presented by these materials. The TiO2 photocatalyst, mainly in its anatase form, is the most studied nanomaterial for the photodegradation, because of its low cost, abundance, nontoxicity, and stability [14 16]. In the case of soil remediation, the decontaminating agent has to be added directly in the middle favoring the contact of the biota with the material, besides the possibility of this being dragged into the groundwater. In this case, the iron nanoparticles (Fe-nano) are the most used material in this environment, mainly to reduce the toxicity of chromium-contaminated soils by the reduction of Cr61 for Cr31, as well as in the reduction of organochlorine compounds [17]. Probably, the most prominent nanomaterial in commercial applications at the moment is nanosilver (Ag-nano) that are nanoparticles of silver in the range of 1 and 100 nm in size [18 20]. Due to its potent bactericidal activity, this material has been incorporated in different commercial products in the medical hospital area, shoes and sneakers, containers for food storage, washing machines, air conditioners, etc. Also, it can be found in bone prostheses, implants, disinfection of surgical instruments, biosensors, and among many others [21]. Silver on a macroscopic scale does not present a harmful effect to humans, except in cases of abnormal exposure. Recent studies have shown that these particles, when inhaled, can be bioaccumulated in the brain and when absorbed through the skin can damage fundamental cellular structures, such as mitochondria [22]. Also, DNA fragmentation was found in the bone marrow, spleen, liver, kidneys, and peripheral blood cells of rats [21]. Thus a growing number of studies show that nanoparticles may play a role in many chronic diseases that were previously attributed only to genetic factors and lifestyle [10]. In this context the nanoparticles toxicity refers to the ability of the particles to affect the normal physiology as well as to interrupt directly the normal structure of organs and tissues of humans [23]. The small size of nanomaterials leads to concern about whether they can cross biological membranes and thus be taken up by cells and organs. In addition, small particles can accumulate deep in the lungs and remain there for a long period [24]. Furthermore, human exposure can occur during the various phases of the life cycle of the nanomaterial, from its synthesis and production to inclusion in products [9]. The distribution and disposal of nanomaterials in the human body can influence the toxic effects and are dependent on their nature and property. The size of the nanoparticle influences the potential of penetration in organisms, for the smaller the particle, the greater its reactivity. Nanoparticles of size equal to or smaller than 35 nm are able to permeate the blood brain barrier, while nanoparticles up to 100 nm can penetrate the cell membrane [25]. The skin is the largest organ in the body and protects the body against diseases caused by organisms, toxic chemicals, and mechanical damage. Nanoparticles are not able to penetrate easily into intact skin or through superficial lesions on the skin. However, they can be deposited in the hair follicles, and this pathway is used in medicine for the release of drugs or vaccines bound to nanoparticles, which are subsequently delivered to the body [26].

Safety risk, ELSI (ethical, legal, social issues), and economics of nanomaterials

439

The interaction of metallic nanoparticles with the biological systems showed the need to evaluate the toxicity of silver nanoparticles. For this purpose, a study observed an increase in inflammatory responses, as well as toxicity in important organs such as the liver and kidneys after oral administration of formulations of different sizes. So, it is to understand the mechanisms that determine the behavior of nanoparticles, not only for the development of this technology but also in the attempt to predict the toxicological responses to nanomaterials [27,28]. In order to enter a cell, the nanoparticle has to cross the cell membrane, which separates the internal components of the cell from the outside (Ortiz, 2014). In this sense, the cell membrane can absorb the nanoparticles when they reach the cells by several processes; one of them is endocytosis that consists of invaginating the cell wall on the particle until it is completely enclosed. The transdermal route is also an essential way of entry when it comes to the use of cosmetic or personal care products containing nanomaterials in their composition. There is also another process that has recently been proposed, which consists of the entry of particles by means of organelles, which are a group of lipids specialized to transport particles, being one of the same mechanisms used by viruses to enter the cells [9,29]. After absorption, the nanoparticles can translocate to the circulatory and lymphatic system, being able to reach diverse tissues and organs, altering their functions. Also, some nanoparticles, depending on their composition and size, can produce irreversible damage to cells due to oxidative stress or organelle injury [10,30]. However, it is believed that the highest risk of contamination by nanoparticles to terrestrial organisms is due to their inhalation, mainly in the professional context. The respiratory system represents an unique target for the potential toxicity of nanoparticles due to the fact that in addition to being the portal of entry for inhaled particles, it also receives the entire cardiac output [9,31,32]. Besides, respirable particles of nanometric size will have access to the alveoli, the location of gas exchange and, generally, the most vulnerable part of the lungs [33]. After inhalation, the nanoparticles deposit along the entire respiratory tract, from the nose and pharynx, and after being deposited in the pulmonary epithelium, the nanoparticles appear to translocate to extrapulmonary sites, reaching other organs by different mechanisms and pathways. One of these mechanisms would be transcytosis, in which the particles are carried into the bloodstream, or transported by the lymphocytes, resulting in the wide distribution of nanoparticles to the whole body [16,34]. However, the blood air barrier is a structure present in the lungs that controls gas exchange in the lungs through pressure and concentration gradients. However, all other foreign materials in our breathable air will also be inhaled if they are small enough, such as bacteria, viruses, including nanomaterials. Therefore if this barrier is very thin, the chance that the nanoparticles will cross and enter our body is high [26]. However, in humans, it is known that when deposition of nanoparticles occurs in the alveoli, there is depuration through macrophage-mediated mechanisms.

440

Handbook of Nanomaterials in Analytical Chemistry

According to the US Environmental Protection Agency (EPA) (USEPA), more than 60,000 deaths per year are attributed to the inhalation of atmospheric nanoparticles, and it is reported that this contamination through respiration can reach organs such as the brain and heart. The internal air can be 10 times more polluted than the outside air [35]. In this sense, nanoparticles are generated in activities such as cooking, smoking, and burning candles and fireplaces [10]. However, since 2001 the EPA has played a role in supporting research and definition of directions for research to develop safe environmental applications for nanotechnology as well as for understanding the potential implications for human and environmental health, destining for this purpose, only for the year 2016, the amount of US$15.3 million [36]. In the EU, the European Agency for Safety and Health at Work estimates that 300,000 400,000 jobs directly deal with nanotechnology, but there is only one study that is known in the United States which has been concerned with inhalation and skin exposure to nanotubes of carbon during the handling of unrefined material [37]. A study has shown that the risk of exposure to large concentrations of these particles is high, and air quality must be closely monitored during operations [38]. Besides, it is known that nanomaterials incorporated into food or in even food packaging, as well as contaminated soils or water, can be absorbed by the intestines of mammals and therefore can increase systemic effects [9]. These effects may arise after oral exposure because the nanoparticles are distributed to the kidneys, liver, spleen, lungs, brain, and gastrointestinal tract [39]. Absorption via the lung, skin, or intestinal tract may be in the form of particles contained in phagocytic cells, such as macrophages, in individual particles or aggregates of free particles or associated with serum proteins [40]. After absorption, the nanoparticles can travel to the lymphatic and circulatory system and can reach various organs and tissues, including the brain [41]. Several studies in rodents have investigated the consequences of exposure to nanomaterials, mainly by inhalation, with the occurrence of lung lesions, inflammation and induce oxidative stress [42,43], formation of tumors, and confirmed their toxic potential. The inflammatory response that results in the production of oxygen-free radicals has the potential to contribute for the development of neoplasias [41]. Nanomaterials can induce mainly genotoxic effects mediated by oxidative stress through their interaction with cellular constituents, including mitochondria and NADPH oxidases bound to the cell membrane or through the depletion of antioxidants (glutathione and catalase enzymes) [44]. In this context, studies related to the interaction of nanomaterials, doses, and biological systems are of fundamental importance, mainly looking for tests to verify mediators of oxidative stress against cellular injury, toxicity, and mutagenicity, to contribute to the safe and effective use of these systems [45]. However, to date, there are no specific and standardized tests for the toxicity assessment of nanomaterial samples. This difficulty compromises the comparison of results and consensus on their toxicity.

Safety risk, ELSI (ethical, legal, social issues), and economics of nanomaterials

441

In this context the nanoparticles when present in the body are widely absorbed and eliminated by the reticulohistiocytic systems (RHS). This system represents a network of cells distributed throughout the body within its organs. The function of the RHS is the inactivation and elimination of dead cells, bacteria, viruses, and small particles infiltrated as the nanoparticles [26].

17.3

Economics, modern policy, and legalization of nanotechnology

In a worldwide spectrum, there is not yet a specific regulatory framework to establish definitions of nanomaterials and the characterization and evaluation of their safety. For nanotechnology to reach its full potential, a balance is needed between risk regulation and the development of technology for the benefit of society [46]. The first initiatives aiming to obtain information on the areas that need to be deepened to evaluate the harmful effects of nanomaterials on health and the environment were carried out by the United Kingdom Royal Society and Royal Academy of Engineering [47] in the study on the environmental risks to health, safety, and the ethical and social implications associated with the development of nanotechnology, the areas where regulation should be considered, thus avoiding the release of nanoparticles until more scientific knowledge about their effects were obtained [36]. In Brazil, there are still no regulatory norms of the Ministry of Labor, nor standardization of Brazilian Association of Technical Standards (ABNT) on nanomaterials [48], and there are also neither agreed protocols for nanoparticle toxicity tests nor standardized protocols to evaluate their environmental impacts. However, the Brazilian legal system offers regulations for the identification of responsibility, measurement of the parameters for the sanction, and establishment of cautious conduct (the constitutional principle of precaution) in the treatment of nanotechnological risk, through various legal instruments such as The Civil Code, The National Policy on Solid Waste, the National Environmental Policy Law, the Consumer Defense Code, the Nuclear Accident Law [36]. On an international scale, the European NANoREG project, which deals with international nanotechnology regulations, was created. It has as its members the main global bodies dealing with regulation such as the Organization for Economic Co-operation and Development, the International Organization for Standardization (ISO), and the European Chemicals Agency (ECHA), involving 64 institutions from 15 countries in Europe, Australia, Canada, South Korea, the United States, and Japan [49]. NANoREG aims to provide legislators with a set of tools for risk assessment and decision-making tools in the short and medium term through data analysis and risk assessment, including exposure, monitoring, and control, to a selected number of nanomaterials already used in products; to develop, in the long term, new testing strategies, adapted to a large number of nanomaterials, where many factors can affect their environmental and health impact; to establish close collaboration

442

Handbook of Nanomaterials in Analytical Chemistry

between governments and industry on the knowledge needed to properly manage risks and provide the basis for conventional approaches, mutually acceptable data sets, and risk management practices [48]. Besides, under the CLP (Certification, Labeling and Packaging) Regulation, substances placed on the European market, including nanomaterials, are required to be notified to the ECHA according to the hazard classification, regardless of their tonnage. In this sense, regulation for nanomaterials is advanced in the EU throughout the community and in each member state. As a result a sectoral dialog has been established with the EU on the regulation of nanotechnology-based products to support the process that will lead to the development of regulatory framework(s) for nanotechnology in Brazil. For the regulation of a nanomaterial the USEPA requires manufacturers to provide scientific evidence that its use does not cause environmental damage and public health risks. Thus specific studies are required on the behavior that each type of nanomaterial present. ISO certification for nanomaterials encompasses the standardization of three fundamental aspects: (1) terminology and nomenclature; (2) characterization; and (3) health, safety, and environmental risk assessment. The spectrum of application of nanomaterials, given their versatility and a large number of functionalities—without a doubt—inaugurated a real technological revolution. There are currently more than 1300 products containing nanotechnology in the global market, and it is estimated that industrial production of nanostructured materials is expected to reach 100,000 t over the next decade. In spite of the enormous advantages and applications expected for nanotechnologies—and here the nanomaterials are important actors, it is also known that these nanostructures can cause deleterious effects to humans and the environment, so it is absolutely urgent the need for directives for their use safe. An important point to note is the difficulty in comparing the toxicity results of nanoscale materials available in the current literature, due not only to the wide variety of methods of synthesis and preparation of nanomaterials but also to the lack of systematic work reporting an adequate physical chemical characterization of the sample used in the studies. In addition, there is a lack of adequate colloidal dispersion protocols and robust biological models. However, as nanotechnology revolutionizes society by introducing new products and processes, it also brings growing concern about the risks associated with its different uses. In this sense, we also need to learn more about how nanomaterials are changing the way we create products in the modern industry [1,2].

17.4

Conclusion and future trends

Nanomaterials will have impacts on all life sciences and technologies, and the nanosystems are being designed and built with the ability to interact with DNA and cells. To evaluated nanomaterial, we must consider the physicochemical properties,

Safety risk, ELSI (ethical, legal, social issues), and economics of nanomaterials

443

the magnitude, duration and frequency of exposure, the susceptibility of organisms, and, mainly, the routes of introduction and contact with the biosystems, these being directly interconnected with the nanotoxicity. It may be concluded that existing data on the toxicity of nanomaterials are still limited and conflicting, and many study still need to be directed to this area. The toxicological evaluation of the nanometric scale of particles and fibers will contribute to some issues related to the use of nanomaterials in commercial products. Therefore the understanding of the cytotoxicity mechanisms of a given nanomaterial is fundamental for defining its impact on health and consumer protection strategies. The effect of the interaction between cells and nanoparticles requires more advanced knowledge. In general, toxicological studies involving nanoparticles are still scarce, and their results are controversial when compared to each other. Most studies indicate an acute toxic effect, which demonstrates the need for a better understanding of the effects of these materials before they are used in everyday processes and products. The environmental risk analysis of nanomaterials depends, mainly, on the regulatory structure, involving the generation of protocols, which should be based on a multidisciplinary interaction in order to obtain a risk assessment in the most reliable manner. With the increase of research in this area, which encompasses the environmental monitoring of nanoparticles, it will be possible to evaluate the risk of contamination by these materials. Thus new legislation should emerge shortly indicating guideline values for each nanomaterial and each situation, in addition to new treatment technologies for this type of waste. However, there is a need for a specific or unified global regulatory framework for nanomaterials, since products are being registered in different countries, often according to their type, by their respective regulatory agencies, analyzing each case individually. Thus its production, commercialization, and disposal can be carried out adequately and sustainably. Therefore assessing the overall risk of a nanoproduct is a challenge, as it requires knowledge of its general characteristics, the way it is produced, where and how the nanomaterial is used, at what concentration, and how it is eliminated. The knowledge of the risks nanomaterials cause to the environment will be important, so that their production, commercialization, and disposal are done appropriately and sustainably. Therefore to commercialize safe products, they must comply with the standards required by the legislation regarding environmental and public health aspects. In addition, it is essential to think about the issue of ethics in nanotechnology to develop a responsible attitude toward the future of society and humanity as a whole, allowing future generations to have a better environment considering a holistic aspect. In this sense, the objective of analyzing ethical aspects of nanotechnologies is also to develop a critical sense of the benefits and risks of potential applications involving nanotechnology, as well as to inform about how this science can affect our health. Therefore in adopting an approach to assess and manage the risk-based impact of nanoparticles, it is also necessary to know and understand the nature and extent of human and environmental exposure, as well as conduct studies that monitor risks at all stages of the life cycle of nanomaterials produced.

444

Handbook of Nanomaterials in Analytical Chemistry

References [1] C.M. Hussain, Handbook of Nanomaterials for Industrial Applications, vol. 1, Elsevier, 2018. 1142 pp. [2] C.M. Hussain, Nanomaterials in Chromatography: Current Trends in Chromatographic Research Technology and Techniques, vol. 1, Elsevier, 2018. 554 pp. [3] Project on Emerging Nanotechnologies—Nanotechnology Consumer Product Inventory (2018), Washington, DC, 2015. Available from: ,http://www.nanotechproject.org/cpi/. (accessed December 2018). [4] Statnano, Nanotecnolology Products Database. Available from: ,https://product.statnano.com/., 2019 (accessed June 2018). [5] Market Spotlight, Nanotechnology market to reach $64.2 billion in 2019, in Advanced Materials & Processes, February 2015, 2015. Available from: ,https://www.asminternational.org/c/portal/pdf/download?articleId 5 25986127&groupId 5 10192. (accessed July 2018). [6] Nanodatabase. Available from: ,http://nanodb.dk/en/analysis/consumer-products/ #chartHashsection., 2019 (accessed January 2019). [7] Nanofutures, European initiative for sustainable development by Nanotechnologies. Available from: ,http://nanofutures.eu/., 2019 (accessed January 2019). [8] F.J. Kelly, T. Zhu, Transport solutions for cleaner air, Science 352 (2016) 934 936. [9] H. Louro, T. Borges, M.J. Silva, Nanomateriais manufaturados: Novos desafios para a sau´de pu´blica, Revista Portuguesa de Sau´de Pu´blica 20 (2013) 1 13. [10] C. Buzea, I.I. Pacheco, K. Robbie, Nanomaterials and nanoparticles: sources and toxicity, Biointerphases 4 (2007) MR17 MR71. [11] S.B. Lovern, J.R. Strickler, R. Klaper, Behavioral and physiological changes in Daphnia magna when exposed to nanoparticle suspensions (titanium dioxide, nano-C60 and C60HxC70Hx), Environ. Sci. Technol. 41 (2007) 4465. [12] D.Y. Lyon, L.K. Adams, J.C. Falkner, P.J.J. Alvarez, Antibacterial activity of fullerene water suspension: effects of preparation method and particle size, Environ. Sci. Technol. 40 (2006) 4360 4366. [13] D.S.T. Martinez, O.L. Alves, Interac¸a˜o de nanomateriais com biossistemas e a nanotoxicologia: na direc¸a˜o de uma regulamentac¸a˜o, Cienc. Cult Sa˜o Paulo 65 (2013) 32 36. [14] K. Iketani, R. Sun, M. Toki, K. Hirota, O. Yamaguchi, Sol gel-derived TiO2/poly (dimethylsiloxane) hybrid films and their photocatalytic activities, J. Phys. Chem. Solids 64 (2003) 507 513. [15] A. Rani, R. Reddy, U. Sharma, P. Mukherjee, P. Mishra, A. Kuila, et al., A review on the progress of nanostructure materials for energy harnessing environmental remediation, J. Nanostruct. Chem. 8 (2018) 255 291. [16] Y. Chen, J.C. Crittenden, S. Hackney, L. Sutter, D.W. Hand, Preparation of a novel TiO2 p-n junction nanotube photocatalyst, Environ. Sci. Technol. 39 (2005) 1201 1208. [17] Nanotec, Nanotechnology and nanoscience. Available from: ,http://www.nanotec.org. uk/finalReport.htm., 2019 (accessed June 2018). [18] S. Prabhu, E.K. Poulose, Silver nanoparticles: mechanism of antimicrobial action, synthesis, medical applications, and toxicity effects, Int. Nano Lett. 2 (2012) 32. [19] P.J. Pulit, K. Stoktosa, M. Banach, Nanosilver products and toxicity, Environ. Chem. Lett. 13 (2015) 59 68.

Safety risk, ELSI (ethical, legal, social issues), and economics of nanomaterials

445

[20] B. Sch¨afer, J. Brocke, A. Epp, M. Go¨tz, F. Herzberg, C. Kneuer, et al., State of the art in human risk assessment of silver compounds in consumer products: a conference report on silver and nanosilver held at the BfR in 2012, Arch. Toxicol. 87 (2013) 2249 2262. [21] V.S. Zhurkov, O.N. Savostikova, V.V. Yurchenko, E.K. Krivtsova, M.A. Kovalenko, L.V. Murav’eva, et al., Features of the Mutagenic and Cytotoxic Effects of Nanosilver and Silver Sulfate in Mice, Nanotechnol Russia 12, 2017, 667 672 [22] X. Chen, J.H. Schluesener, Nanosilver: a nanoproduct in medical application, Toxicol. Lett. 176 (2008) 1 12. [23] L. Yildirimer, N.T. Thanh, M. Loizidou, A.M. Seifalian, Toxicology and clinical potential of nanoparticles, Nano Today 6 (2011) 585 607. [24] D.W.S. Leal, R. Hohendorff, Era das nanotecnologias no mercado consumidor: a inserc¸a˜o dos “nanoprodutos” ao cotidiano e o direito a` informac¸a˜o, 2 (2018) 286 302. [25] M.M. Sufian, J.Z.K. Khatlak, S. Yousaf, Safety issues associated with the use of nanoparticles in human body, Photodiagn. Photodyn. Ther. 19 (2017) 67 72. [26] Nanopartikek. Information about nanomaterials and their safety assessment. Available from: ,https://www.nanopartikel.info/en/nanoinfo/body-barriers/2388-nanoparticlesand-the-lung., 2019 (accessed January 2019). [27] B. Fadeel, A.E. Garcia-Bennett, Better safe than sorry: understanding the toxicological properties of inorganic nanoparticles manufactured for biomedical applications, Adv. Drug Deliv. Ver. 62 (2010) 362 374. [28] M.V.D.Z. Park, A.M. Neigh, J.P. Vermeulen, L.J. de la Fonteyne, H.W. Verharen, J.J. Briede´, et al., The effect of particle size on the cytotoxicity, inflammation, developmental toxicity and genotoxicity of silver nanoparticles, Biomaterials 32 (2011) 9810 9817. [29] J. Shin, S.M. Abraham, Caveolae--not just craters in the cellular landscape, Science 293 (2001) 1447 1448. [30] A. Elsaesser, C.V. Howard, Toxicology of nanoparticles, Adv. Drug Deliv. Rev. 64 (2012) 129 137. [31] A.J. Ferreira, J. Cemlyn-Jones, C.C. Robalo, Nanoparticles, nanotechnology and pulmonary nanotoxicology, Rev. Port. Pneumol. 19 (2013) 28 37. [32] E. Bermudez, J.B. Mangum, B.A. Wong, B. Asgharian, P.M. Hext, D.B. Warheit, et al., Pulmonary responses of mice, rats, and hamsters to subchronic inhalation of ultrafine titanium dioxide particles, Toxicol. Sci. 77 (2004) 347 357. [33] P. Laux, C. Riebeling, A.M. Booth, J.D. Brain, J. Brunner, C. Cerrillo, et al., Biokinetics of nanomaterials: the role of biopersistence, Nanoimpact 6 (2017) 69 80. [34] G. Oberdo¨rster, E. Oberdo¨rster, J. Oberdo¨rster, Nanotoxicology: an emerging discipline evolving from studies of ultrafine particles, Environ. Health Perspect. 11 (2005) 823 839. [35] EPA—Environmental Protection Agency. Available from: ,https://www.epa.gov/airtrends., 2019 (accessed January 2019). [36] L.G. Nolasco, N. Santos, Avanc¸os nanotecnolo´gicos e os desafios regulamentares, Rev. Fac. Direito UFMG 71 (2017) 375 420. [37] A.D. Maynard, P.A. Baron, M. Foley, A.A. Shvedova, E.R. Kisin, V. Castranova, Exposure to carbon nanotube material: aerosol release during the handling of unrefined single-walled carbon nanotube material, J. Toxicol. Environ. Health 67 (2004) 87 107. [38] K. Hund-Rinke, M. Simon, Ecotoxic effect of photocatalytic active nanoparticles TiO2 on algae and daphnids, Environ. Sci. Pollut. Res. 13 (2006) 225 232.

446

Handbook of Nanomaterials in Analytical Chemistry

[39] T. Forbe, M. Garcı´a, E. Gonzalez, Potential risks of nanoparticles Riscos potenciais do nanopartı´culas, Ciˆencia e Tecnologia de Alimentos 31 (2011) 835 842. [40] P.J.A. Borm, D. Robbins, S. Haubold, T. Kuhlbusch, H. Fissan, K. Donaldson, et al., The potential risks of nanomaterials: a review carried out for ECETOC, Part. Fibre Toxicol. 3 (2006) 11 35. [41] V. Stone, K. Donaldson, Nanotoxicology: signs of stress, Nat. Nanotechnol. 1 (2006) 23 24. [42] M.R. Miller, C.A. Shaw, J.P. Langrish, From particles to patients: oxidative stress and the cardiovascular effects of air pollution, Future Cardiol. 8 (2012) 577 602. [43] K. Donaldson, L. Tran, L.A. Jimenez, R. Duffin, D.E. Newby, N. Mills, et al., Combustion-derived nanoparticles: a review of their toxicology following inhalation exposure, Part. Fibre Toxicol. 2 (2005) 10. [44] N.R. Jacobsen, Mutagenicity, Genotoxicity and Inflammation Caused by Nanoparticles (Thesis), Faculty of Health Sciences, Copenhagen, 2008 48:451 461. [45] S. Elmore, Apoptosis: a review of programmed cell death, Toxicol. Pathol. 35 (2007) 495 516. [46] S.M. Hankin, N.E.D. Caballero, Regulac¸a˜o da nanotecnologia no Brasil e na Unia˜o Europeia. Available from: ,file:///C:/Users/marke/Downloads/1-dialogos_setoriais__nanotecnologia_portugues%20(1).pdf., 2014 (accessed August 2018). [47] United Kingdom Royal Society & The Royal Academy of Engineering, Nanoscience and nanotechnologies: opportunities and uncertainties. Available from: ,http://www. raeng.org.uk/publications/reports/nanoscience-and-nanotechnologies-opportunities., 2004 (accessed June 2018). [48] A.P. Ferreira, S. Sant, A Nanotecnologia e a Questa˜o da sua Regulac¸a˜o no Brasil: Impactos a` Sau´de e ao Ambiente, Rev. Uniandrade 16 (2015) 119 128. [49] Nanoreg, A common European approach to the regulatory testing of manufactured nanomaterials, Plesmanweg, 1 6, JG Den Haag, Netherlands, 2019. Available from: ,http://www.nanoreg.eu/. (accessed December 2018).

Further reading M. Auffan, L. Decome, J. Rose, T. Orsiere, M. De Meo, V. Briois, et al., In vitro interactions between DMSA-coated maghemite nanoparticles and human fibroblasts: a physicochemical and cyto-genotoxical study, Environ. Sci. Technol. 40 (2006) 4367 4373. H. Becker, F. Herzberg, A. Schulte, M. Kolossa-Gehring, The carcinogenic potential of nanomaterials, their release from products and options for regulating them, Int. J. Hyg. Environ. Health 214 (2011) 231 238. M. Edetsberger, E. Gaubitzer, E. Valic, E. Waigmann, G. Kohler, Detection of nanometersized particles in living cells using modern fluorescence fluctuation methods, Biochem. Biophys. Res. Commun. 332 (2005) 109 116.

Advanced micro- and nanoscale characterization techniques for carbonaceous aerosols

18

Shahadev Rabha1 and Binoy K. Saikia2 1 Polymer Petroleum and Coal Chemistry Group, Materials Science and Technology Division, CSIR-North East Institute of Science and Technology, Jorhat, India, 2Academy of Scientific and Innovative Research, CSIR-NEIST Campus, Jorhat, India

18.1

Introduction

It is attributed that atmospheric aerosol is the second largest climate forcing agent after carbon dioxide and causes various health problems including cardiovascular and pulmonary diseases depicting about 7.6% of the total global deaths in 2015 [1,2]. Atmospheric aerosol with diverse physical and chemical properties is a great challenge in atmospheric science because of its ability to cause a negative impact on human health and the global climate. Furthermore, the level of scientific understanding about their atmospheric source and sinks and physicochemical properties such as chemical constituents, surface chemistry, optical properties, cloud-forming properties, atmospheric life, and mixing condition is still very low, regardless of having tremendous scientific attention during the last 15 20 years (Fig. 18.1). Major scantiness in this area can be endorsed to the carbonaceous aerosol (CA) fraction that contributes about 20% 50% of the total atmospheric aerosol mass, but their formation and transformation processes, radiative forcing, health impact, and numbers of organic species are yet to be fully explained and identified due to the insufficient analytical facility and less number of research in this specific area [4,5]. However, the scientific endeavors are increasing to tackle the challenge with the recent development of modern analytical instruments and methodologies [6 14]. This chapter focuses on the recent advances in microscopic and spectroscopic methods for micro- and nanoscale characterization of atmospheric CA.

18.1.1 Carbonaceous aerosol and their source Atmospheric aerosol, also known as particulate matter (PM), is a suspension of fine solid particles or liquid droplets in the air. They may originate from both natural sources such as sea salt, desert dust, volcanic eruption, and forest fire and anthropogenic sources such as fossil fuels and biomass burning. Atmospheric aerosols are generally classified based on their aerodynamic sizes such as (1) PM10 that are inhalable coarse particles with aerodynamic diameter between 2.5 and 10 μm, (2) Handbook of Nanomaterials in Analytical Chemistry. DOI: https://doi.org/10.1016/B978-0-12-816699-4.00018-9 Copyright © 2020 Elsevier Inc. All rights reserved.

450

Handbook of Nanomaterials in Analytical Chemistry

Figure 18.1 Radiative forcing by various atmospheric compositions (global mean for 2000, relative to 1750). Carbonaceous aerosol such as black carbon and organic carbon shows both direct cooling and warming and indirect cooling effects. Source: Reproduced from J.E. Penner, M. Andreae, H. Annegarn, L. Barrie, J. Feichter, D. Hegg, et al., Chapter 5—Aerosols, their direct and indirect effects. Climate Change 2001: the scientific basis, in: Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, United Kingdom and New York, USA, 2001 [3].

PM2.5 that are fine particles with aerodynamic diameter of 2.5 μm or less, and (3) ultrafine or nanoparticles with diameter of 100 nm or less. They are also named on the basis of their chemical composition such as sulfate aerosol that contains sulfate, nitrate aerosol that contains nitrate, and CA that contains carbon. CA is an unwanted by-product of incomplete combustion of fossil and biomass-based fuels comprising various forms of carbon such as black carbon (BC), elemental carbon (EC), and organic carbon (OC). Depending upon their source of emission, the total carbon content varies from 45% to 90% of mass concentration with particle size range 15 600 nm [15]. CA makes up the major but most unpredictable portion of the atmospheric aerosols that are mostly fine particles, less than 1 μm in aerodynamic diameter [16]. They do not well mixed in the atmosphere because of their particulate form but remain suspended in the air until they settle down or washed out by rain or contribute to cloud formation. They comprise a range of carbonaceous materials from char to highly graphitized BC, and a various complex mixture of OC containing carbon carbon bonds is produced from incomplete burning of biomass and fossil fuels, and atmospheric oxidation of biogenic and anthropogenic volatile organic compounds. It was estimated that, in the year 2000, the global emission of BC from fossil fuel and biomass burning was about 6 8 and 6 9 Tg year21, respectively, and that of OC was about 10 30 and 45 80 Tg year21, respectively [3,17]. Streets et al.

Advanced micro- and nanoscale characterization techniques for carbonaceous aerosols

451

[16] represented a model-based estimate of future emissions of CAs determined by four intergovernmental panel on climate change (IPCC) scenarios A1B, A2, B1, and B2, out to 2030 and 2050 incorporating the fuel use and technology development (Table 18.1). Fig. 18.2A and B shows the global annual average source distribution for anthropogenic BC and OC. The global atmospheric concentration of aerosols and their source location can be obtained through satellite that measures the aerosol optical depth (AOD). AOD is a measure of extinction of solar radiation due to scattering and absorption by aerosols. An AOD of less than 0.1 specifies a clear sky, whereas a value of 1 specifies the very hazy sky due to the presence of dense aerosols. Fig. 18.2C E shows the global average AOD of CA, BC, and organic matter, respectively. Fig. 18.2F indicates that aerosol is mainly concentrated in the tropics, where biomass burning is the major emission source of CA [19].

18.1.2 Importance of nanoscale characterization It is well established that CA plays a major role in global climate forcing [1,8,14]. Fig. 18.3 illustrates a general model of direct and indirect effects of CA on climate. The health problems due to PM are directly linked to the particles size, composition, and concentration. Fig. 18.4 shows how different size fraction of aerosol has a different level of impacts on human health. Knowledge about some of the key aerosol properties has been greatly improved in laboratory and field experiments using recently advanced instrumentation, but how much further information need to acquire to develop accurate and predictive models of their impacts on climate and human health is more important. For example, it is reported that aerosols are associated with cardiovascular diseases such as atherosclerosis, ischemic heart disease, and chronic obstructive pulmonary disease; however, their possible molecular mechanism still unrevealed [20,21]. Also, CAs act as condensation nuclei but what chemical interactions affect the ability of the aerosol particle to nucleate cloud is yet to describe [22]. Generally, aerosol particles are characterized in two size ranges—PM10 (particle , 10 μm) and PM2.5 (particle , 2.5 μm); however, particles smaller than PM2.5 have more peculiar characteristics and are more harmful to the human health. Nanoscale characterization may provide a wider range of information to describe the physical and chemical properties of the CA particle and their role in the atmospheric chemistry.

18.2

Analytical characterization techniques

Although atmospheric aerosol is not a new subject in the current world, with a large number of researches have been performed or going on, there is a lot of uncertainties in the area that encourage the development of methods and techniques for their measurement. Numerous analytical techniques have been developed in recent years that facilitate nanoscale, physicochemical characterization of various engineered nanomaterials [23,24], and also the aerosol particles in the laboratory as well as

Table 18.1 Emission factors (g kg21) for the major black carbon (BC) source types in 1996, 2030, and 2050. Sector

Fuel

Combustor type

Sharea (%)

1996

2030 A1B

b

b

2050 A2

B1 b

B2 b

A1B b

b

A2

B1 b

B2

N/A

b

N/A

N/Ab

Biomass burning Biomass burning Residential

Grassland

N/A

21.2

N/A

N/A

N/A

N/A

N/A

N/A

Tropical forest

N/A

12.4

N/Ab

N/Ab

N/Ab

N/Ab

N/Ab

N/Ab

N/Ab

N/Ab

N/Ab

Wood

6.2

3.9

3.9

3.9

3.9

3.9

3.9

3.9

3.9

3.9

Residential

Agricultural waste Crop residues

Traditional cookstove All

4.8

6.5

6.5

5.7

3.3

3.3

6.5

4.8

3.3

3.3

N/A

4.0

N/Ab

N/Ab

N/Ab

N/Ab

N/Ab

N/Ab

N/Ab

N/Ab

N/Ab

Superemitting vehicles Vehicles/Opacity regs. Off-road equipment Uncontrolled

3.9

12.0

12.0

12.0

12.0

12.0

12.0

12.0

12.0

12.0

3.3

3.5

3.5

3.5

3.5

3.5

3.5

3.5

3.5

3.5

3.2

5.5

3.1

3.2

3.1

3.1

3.0

3.0

3.0

3.0

3.1

20.0

20.0

20.0

20.0

20.0

20.0

20.0

20.0

20.0

N/A

2.9

N/Ab

N/Ab

N/Ab

N/Ab

N/Ab

N/Ab

N/Ab

N/Ab

N/Ab

Brick kiln All Vehicles/Euro regs. Tractors Open fire

2.6 2.6 2.5

10.0 3.7 1.5

10.0 1.9 0.2

10.0 3.3 0.2

10.0 1.9 0.2

10.0 1.9 0.2

10.0 1.9 0.2

10.0 2.7 0.2

10.0 1.9 0.2

10.0 1.9 0.2

2.5 2.2

4.0 7.7

2.1 7.7

2.1 7.7

2.1 7.7

2.1 7.7

2.0 7.7

2.0 7.7

2.0 7.7

2.0 7.7

Biomass burning Transport

Diesel

Transport

Diesel

Industry

Diesel

Industry Biomass burning Industry Residential Transport

Cooking process Extratropical forest Coal Dung cake Diesel

Transport Residential

Diesel Coal

Residential

Coal

Industry Residential Transport

Cooking process Wood Heavy fuel oil

Industry

Diesel

a

Traditional cookstove Controlled

2.1

7.7

6.2

6.2

6.2

6.2

4.5

4.5

4.5

4.5

1.8

5.8

2.3

2.7

2.0

2.4

1.8

1.8

1.7

1.8

Heating stove International shipping Off-road superemitter

1.7 1.5

15.0 1.8

8.8 1.2

9.5 1.2

7.7 1.2

8.8 1.2

7.6 1.0

8.0 1.0

7.5 1.0

7.6 1.0

1.3

17.0

17.0

17.0

17.0

17.0

17.0

17.0

17.0

17.0

Percentage contribution of this sector/fuel/technology combination to total BC emissions in the base-year 1996 inventory. For biomass burning, BC and organic carbon emission factors are used directly from the work of Andreae and Merlet [18], instead of being derived from PM emission factors, and are constant over time. Source: Reproduced from D.G. Streets, T.C. Bond, T. Lee, C. Jang, On the future of carbonaceous aerosol emissions, J. Geophys. Res. 109 (2004) (D24212) 1 19. doi:10.1029/2004JD004902.

b

454

Handbook of Nanomaterials in Analytical Chemistry

Figure 18.2 AOD of CAs. Panels (A) and (B) show the annual average source strength in kg km22 h21 for anthropogenic sources of BC and OM, respectively. (C), (D), and (E) depict the AOD of CA, BC, and OM, respectively. (F) MODIS AOD of February 2018. AOD, Aerosol optical depth; CA, carbonaceous aerosol; BC, Black carbon; OM, organic matter. Source: (A and B) Reproduced from J.E. Penner, M. Andreae, H. Annegarn, L. Barrie, J. Feichter, D. Hegg, et al., Chapter 5—Aerosols, their direct and indirect effects. Climate Change 2001: the scientific basis, in: Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, United Kingdom and New York, USA, 2001; (C E) Reproduced from C.E. Chung, V. Ramanathan, D. Decremer, Observationally constrained estimates of carbonaceous aerosol radiative forcing, PNAS 109 (29) (2012) 11624 11629. doi:10.1073/pnas.1203707109; (F) Retrieved from NASA Earth Observatory.

field studies. Microscopy and spectroscopy are the two important techniques used by researchers to study CA, which are broadly discussed in the following sections.

18.2.1 Microscopic techniques Microscopy, especially electron microscopy, either in its transmission or scanning mode with nanometer resolution, is a promising technique for morphological characterization of aerosol particle [25]. Electron microscopy with high spatial

Advanced micro- and nanoscale characterization techniques for carbonaceous aerosols

455

Figure 18.3 Schematic diagram of the direct and indirect climate effect of CA. BC causes direct heating by absorbing incoming solar radiation and outgoing IR radiation, and OC causes direct cooling by scattering incoming radiation. Indirectly, CA acts as CCN or IN affecting the cloud formation processes. BC, Black carbon; CA, carbonaceous aerosol; CCN, cloud condensation nuclei; IR, infrared; IN, ice nuclei; OC, organic carbon. Source: Modified from http://www.isac.cnr.it/cimone/aerosol_properties (accessed 25.09.18).

resolution (,1 5 nm) allows more detail observation and detection of smaller particles (20 30 nm) and is capable of identifying three-dimensional structures. The use of electron-beam techniques for analysis of CA has largely increased in the last 10 15 years due to their improvement in revealing chemical information of single particles [26]. Particularly, the coupling of spectroscopy with microscopy has facilitated a more detailed understanding of physicochemical mixing state of aerosol. However, first, its high vacuum environment is supposed to cause loss of semivolatile components and second, the high-energy electrons can cause damage to soft materials such as OC in particles. Some useful techniques for studying CA are described in the following sections.

18.2.1.1 Scanning electron microscopy with energy-dispersive X-ray spectroscopy Scanning electron microscopy (SEM) technique has been used for last more than 40 years to study the atmospheric aerosol, initially the coarse particles ( . 2.5 μm) and

456

Handbook of Nanomaterials in Analytical Chemistry

Figure 18.4 Different size fractions of aerosols (PM) and their various human health effects. Smaller particles have more penetration capacity deep into the cardiovascular system leading to cardiovascular diseases. PM, Particulate matter.

recently the fine (,2.5 μm) and even ultrafine particles (0.1 μm) [26]. SEM scans samples with a focused high-energy electron beam and delivers images with highresolution surface information. The schematic diagram of an SEM is illustrated in Fig. 18.5. The electron source is thermoelectron emitted from a filament made of a thin tungsten wire (0.1 mm) by heating the filament at high temperature (about 2800K). The high-energy electrons upon interaction with sample materials generate a variety of signals such as secondary electron (SE), backscattered electron (BSE), and X-rays revealing information about the external morphology and chemical composition of the materials in the sample. SE produces an image with sharpness and depth of focus resulting in a three-dimensional view. Image due to BSE depends on the number of BSEs produced due to the interaction between the electron beam and the sample, which depends on the atomic number (Z) of the materials in the sample and illustrates contrasting brightness [27]. SEM requires microscopically smooth and conductive materials such as polycarbonate filters, because the high accelerating voltage (5 25 kV) that interacts with the sample may build up charge from the electron bombardment if the material is nonconducting and cannot dissipate, and thus degrading image quality. SEM uses a BSE detector and SE detector to produce an image; however, the addition of another detector, the high-angle annular dark field detector for transmitted electron, improves the detection of submicron particles far better. Scanning transmission electron microscopy (TEM) (STEM) requires a

Advanced micro- and nanoscale characterization techniques for carbonaceous aerosols

457

Figure 18.5 Schematic diagrams of SEM and TEM with their core components. SEM, Scanning electron microscopy; TEM, transmission electron microscopy. Source: Reproduced from B.J. Inkson, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) for Materials Characterization, Woodhead Publishing, 2016 (Chapter 2). https://doi.org/10.1016/B978-0-08-100040-3.00002-X.

thin electron transparent sample that is generally prepared by using TEM grid. STEM image also depends on the atomic composition of the materials in the sample (Z-contrast image) and thickness, giving bright-field image and compositional distinctions with higher spatial resolution up to 0.2 nm at 200 kV accelerating voltage [28]. Field-emission scanning electron microscope (FESEM) is another advanced SEM technique with ultrahigh-resolution imaging (,2 nm spatial resolution) at a low accelerating voltage (0.5 30 kV) and high vacuum (B10 6 Pa). The electron emission is caused by field emitter gun by a strong electric field from the surface of a thin tungsten wire (10 100 nm) that is about 1000 times smaller than that of traditional SEM with a thermal gun. FESEM is suitable for imaging surface sensitive, nonconductive, and carbonaceous nanoparticles where high-energy beam is not always required [29]. These SEM techniques are functional for determining the size distribution and composition of CA [30]. CA from fossil fuel and biomass combustion that is revealed in various SEM analyses, such as BC or soot particles, is in the submicrometer to nanometer size range [31 33]. Fig. 18.6A shows the soot particle with irregular shapes forming chain-like agglomeration revealed in high-resolution FESEM analysis. Energy-dispersive (ED) X-ray (EDX) spectroscopy is generally coupled with SEMs, which allows chemical characterization of the sample. It measures the X-rays emitted from the specific element when core electrons are ejected from atoms of the materials in the sample and from higher energy to lower energy orbital. EDX provides information about the elemental composition of the material in the specific

458

Handbook of Nanomaterials in Analytical Chemistry

Figure 18.6 Electron and atomic force microscopic images of soot aggregates. (A) FESEM image depicts different shape and size distribution. (B) TEM image showing chain-like structure. (C) High-resolution TEM image of soot particle illustrates onion-like curved, graphitic structures. (D) Topographic AFM image displays the surface roughness of soot aggregates. AFM, Atomic force microscopy; FESEM, field-emission scanning electron microscope; TEM, transmission electron microscopy. Source: (A C) Reproduced from J. Li, M. Posfai, P.V. Hobbs, P.R. Buseck, Individual aerosol particles from biomass burning in southern Africa: 2. Compositions and aging of inorganic particles, J. Geophys. Res. 108 (D13) (2003) 201 212. doi:10.1029/2002JD002310 [31]; (D) Reproduced from Y. Shi, Y. Ji, H. Sun, F. Hui, J. Hu, Y. Wu, et al., Nanoscale characterization of PM2.5 airborne pollutants reveals high adhesiveness and aggregation capability of soot particles, Sci. Rep. 5 (2015) 11232. doi:10.1038/srep11232 [34].

focused point, but information such as oxidation state, covalent bonding, and elements that are lighter than sodium cannot be revealed from EDX [31,35]. Another important successor of SEM is an environmental scanning electron microscope (ESEM) that allows imaging of wet and insulating samples without prior sample preparation. ESEM maintains a gaseous environment instead of a high vacuum, which allows imaging of the hydrated sample in their native environment, and also the charge build-up by the incident electron beam is dissipated by the gas [36]. ESEM is suitable for determination of hygroscopic behavior, cloud, and ice nucleation properties of the aerosol single particle and other properties that are not suitable in high vacuum environment [37 39].

18.2.1.2 Transmission electron microscopy with energy-dispersive X-ray spectroscopy TEM is another advanced and highly sophisticated analytical technique effective for characterization of CA, which has been using in aerosol research as long as

Advanced micro- and nanoscale characterization techniques for carbonaceous aerosols

459

since 40 45 years, but increased in use from the late 1990s and early 2000s [26]. In TEM, high-energy electron beam (150 300 kV) is transmitted through ultrathin (,100 nm) sample at high vacuum (1024 1029 Pa) environment to form an image. A sophisticated system of electromagnetic lenses is used to focus the scattered electrons into an image or a diffraction pattern depending on the mode of operation. Fig. 18.5 shows the schematic diagram of a TEM. It has a high spatial resolution less than 0.1 nm, which allows imaging of smaller particles that are not accessible by SEM [40]. Though, high-resolution TEM (HRTEM) has a resolution of around 0.05 nm that allows determining of even individual atoms of a crystal and its defects [41]. HRTEM uses both the scattered and transmitted electrons to produce an interference image. It is a powerful technique to study the properties of materials on the atomic scale, such as CA nanoparticles. The disadvantage of TEM/HRTEM is the high vacuum and high-energy electron beam that can more easily damage sample and thus limiting its universal applicability. However, to avoid this limit, environmental cells have been added in the recent past for environmental TEM, which allow the analysis of a sample at around ambient pressures and since then it received increasing attention from biological as well as materials scientists [42]. In TEM, chemical characterization can be achieved using EDX or electron energy loss spectroscopy (EELS). EELS uses inelastically scattered electrons, which can give more detail chemical information than the X-rays in EDX. TEM/HRTEM analysis of CA by various researchers has revealed lots of information about their morphological and chemical characteristics. TEM image easily distinguishes soot particles from their unique morphology (Fig. 18.6B). HRTEM image of soot spheres shows a discontinuous onion-like structure of graphitic layer (Fig. 18.6C) [43 46]. It is also revealed that soot also contains aggregates of various carbon nanocrystalline forms such as multiwalled, concentric tubes, shells, spheres, and other structures [9]. Irregular geometry and complex microstructure of soot aggregates may provide active sites for chemical species and hygroscopic properties [45]. HRTEM EELS shows the chemical heterogeneity of soot aggregates [31,46].

18.2.1.3 Atomic force microscopy Atomic force microscopy (AFM) is a versatile and very high-resolution scanning probe microscopy technique suitable for studying materials sample at nanoscale resolution. It provides various types of surface measurements with three-dimensional topography at atomic resolution. An AFM consists of a cantilever with a sharp tip (probe) of the radius of curvature on the order of nanometers. When the probe is brought into the proximity of a sample surface, forces between the probe and sample lead to a deflection of the cantilever. The force imposed by the sample on the probe is used to form a three-dimensional tomographic image of a sample surface. AFM can also measure the mechanical properties of the sample such as adhesive force and stiffness by measuring the forces between the probe and the sample as a function of their mutual separation. The advantage of the AFM over electron microscopy techniques is that it is executed under ambient environment, so there is

460

Handbook of Nanomaterials in Analytical Chemistry

no possibility of changes of sample property by an electron beam or vacuum system, but the lack of chemical information limits its widespread uses. However, the addition of infrared (IR) spectroscopy to AFM can give chemical information to the detailed physical properties [47]. The AFM technique has been used for the characterization of particle morphology, topography, surface tension, hygroscopicity, and mechanical properties of atmospheric aerosol particles since the late 1990s [34,48 50]. Fig. 18.6D is an AFM image that shows the topography with the high surface roughness of soot aggregate.

18.2.2 Spectroscopy techniques For the last two decades, spectroscopy has been used as a powerful analytical technique for chemical characterization of atmospheric aerosol because of its detecting capability up to picogram quantities of materials for both the organic and inorganic compounds [51,52]. Moreover, the recent advances in this technique with improvements in the mass detection limit and spectral quality have made spectroscopy even more powerful tool for analyzing CA, and thus its application in the aerosol research remains significant. In addition, many of these spectroscopy techniques avoid the potential loss of water or semivolatile compounds as they can work at ambient pressure and relative humidity, unlike electron microscope that requires high vacuum condition. Spectroscopy is a broad field with many subdisciplines (e.g., electronic, vibrational) executed with specific spectroscopic techniques (e.g., electron beam, X-ray photon, IR photons, UV visible) and provides specific chemical information (e.g., elemental composition, oxidation state, functional group, surface activity). Some recent techniques that are used by various researchers for CA are discussed briefly in the following sections.

18.2.2.1 Raman spectroscopy Raman spectroscopy is a vibrational spectroscopic technique used to observe molecular vibrations and crystal structures. It provides a characteristic fingerprinting pattern by which substances can be identified. Unlike electron-beam techniques where electronic transitions are used, Raman spectroscopy probes molecular vibrations. It relies on the inelastic scattering or Raman scattering of the monochromatic light, usually from a lesser in the visible, near-IR or near-UV range. The laser light interacts with molecular vibrations, resulting in the shifting of the energy of photons up or down, which gives information about the vibrational mode in the system. Fig. 18.7 shows a schematic diagram of the different energy states involved in Raman spectroscopy technique. The main advantages of Raman spectroscopy that makes its widespread use are that it’s a noncontact and nondestructive analysis technique with high spatial resolution up to submicron scale. Both the organic and inorganic samples in various states such as gas, liquid, solution, solid, crystal, and the emulsion can be measured without any special sample preparation. Raman spectroscopy is a useful technique for characterization of atmospheric aerosol particles. It has high sensitivity and selectivity for chemical speciation [6].

Advanced micro- and nanoscale characterization techniques for carbonaceous aerosols

461

Figure 18.7 Schematic diagram showing the different energy states involved in Raman spectra: an electron is excited from the ground level and falls to the original ground level (Rayleigh scattering), excited from the ground level and falls to a vibrational level (Stokes Raman scattering) and excited from a vibrational level and falls to the ground level (antistokes Raman scattering).

Its uses in the field of aerosol research were started in the late 1970s, but not widely used until the past decade [53]. Raman spectroscopy has been used for investigating the processes where physicochemical mixing state is important such as heterogeneous reactivity, hygroscopicity, and ice nucleation [54 56]. Raman is sensitive to the structural order of carbon atoms that make it a suitable technique for characterization of CA particles [6,57,58]. It shows the graphite-like carbon structure of CA —soot particles (Fig. 18.8) and can derive information about their origin and evolution processes [6,59,60]. Another significance of Raman spectroscopy is the measurement of pH in individual particles, the study of which began very recently. Rindelaub et al. [61] used Raman microspectroscopy technique to determine the pH in individual particle and reported the potential of Raman for direct measurement of aerosol acidity. Although there are some disadvantages associated with Raman such as the particle size that is mostly limited to around 1 3 μm due to the diffraction limit and the autofluorescent emission from the particle itself on excitation with Raman laser, which can be avoided by photo-bleaching or baseline correction. However, the recent development of the technique such as surface-enhanced Raman spectroscopy and tip-enhanced Raman spectroscopy can probe individual submicron to nanoparticles with a diameter below 100 nm [62,63].

462

Handbook of Nanomaterials in Analytical Chemistry

Figure 18.8 Raman spectrum (λ0 5 632.8 nm) of soot particle with band deconvolution revealing graphitic band G. Source: Reproduced from T. Catelani, G. Pratesi, M. Zoppi, Raman characterization of ambient airborne soot and associated mineral phases, Aerosol Sci. Technol. 48 (2014) 13 21. doi:10.1080/02786826.2013.847270.

18.2.2.2 Fourier-transforms infrared spectroscopy Although Fourier-transform IR spectroscopy (FTIR) technique is limited to greater than 5 μm of particle size due to the diffraction limit, it has significance in aerosol studies for understanding the physical and chemical processes involved in heterogeneous reactions, functional group and organic compositions in aerosols, and source apportionment of aerosol particles [64,65]. FTIR measures the absorption of light in the IR region of the electromagnetic spectrum by the molecules, and the absorption relates to the bonds present in the molecules. The frequency ranges are measured as wave numbers usually more than the range 4000 600 cm21. The emission spectrums of the IR source without (background) and with the sample are measured and the ratio of which is directly related to the absorption spectrum of the sample. The presence of various chemical bonds and functional groups in the sample is identified from the resultant absorption spectrum. The advantage of FTIR is that it doesn’t require any special sample preparation, and the sample is not mounted in a vacuum, so both high and low vapor pressure materials can be examined. Recently, the use of attenuated total reflection FTIR (ATR FTIR) has increased because of its enhanced sensitivity and low interference from Teflon filter and the lower size limit is B1 μm of particles. ATR FTIR in combination with quantitative ED electron probe X-ray microanalysis (EPMA), which is also known as low-Z particle

Advanced micro- and nanoscale characterization techniques for carbonaceous aerosols

463

EPMA, can be used for single particle analysis [66 68]. ATR FTIR analysis of carbonaceous particle revealed the presence of various types of functional groups, such as carbonyl carbon (CQO), carbon carbon double bond (CQC), carboxylate ion (COO 2 ), organic nitrates (CONO2) or C O H bending, C O, ammonium ion (NH41 ), and sulfate (SO22 4 ) [68].

18.2.2.3 X-ray photoelectron spectroscopy X-ray photoelectron spectroscopy (XPS) is a powerful technique for the revelation of the surface chemical composition of atmospheric particles. XPS can identify surface elements and their bonding states. The kinetic energy of core shell electrons ejected from elements by monochromatic X-rays is resolved using an electron monochromator. The difference between the energy of ejected electron and incident X-ray (photon) is the electron-binding energy that is specific to the quantum shell energy level and hence the element. XPS has been using for the identification of surface chemical speciation of atmospheric particles since its inception [69 72]. Recently, it has been used to probe size-resolved surface composition, more detailed high-resolution spectra, and heterogeneous reactivity of complex aerosol particles [13,73,74]. Elemental compositions in CA particles may be identified in an XPS survey scan because it spans a broad range of ejected core shell electron energies. Surface chemistry and carbon nanostructure of CA may be quantified by deconvolution of high-resolution scans over the C1s region (Fig. 18.9). It provides identification of the carbon-bound, surface oxygen functional groups, such as hydroxyl, carbonyl, and carboxylic groups and estimates of the relative fractions of

Figure 18.9 XPS analysis of particulate sample (A) survey spectrum and (B) high-resolution C1s spectrum resolved into signals assigned as—(1) elemental; (2) aromatic; (3) aliphatic; (4) C O, C N, C S (5) R2CQO; (6) carbonate; (7) π π elemental; (8) π π aromatic; (9) ( CF2)n PTFE. PTFE, Polytetrafluoroethylene, XPS, X-ray photoelectron spectroscopy. Source: Reproduced from D. Atzei, M. Fantauzzi, A. Rossi, P. Fermo, A. Piazzalunga, G. Valli, et al. Surface chemical characterization of PM10 samples by XPS. Appl. Surf. Sci. 307 (2014) 120 128. doi:10.1016/j.apsusc.2014.03.178.

464

Handbook of Nanomaterials in Analytical Chemistry

sp2 versus sp3 carbon [13,75]. XPS technique has many advantages that are nondestructive and surface sensitive, with the chemical shift. Chemical shifts of the elements allow the qualitative analysis of the different elements while the quantitative analysis leads to the determination of elemental and species concentrations.

18.2.2.4 Time-of-flight secondary ion mass spectrometry Time-of-flight secondary ion mass spectroscopy (ToF-SIMS) allows imaging with high surface sensitivity, with both elemental and molecular information and can be used to explore the surface chemistry of PM [76,77]. ToF-SIMS uses a focused, pulsed particle beam to remove molecules from the very outermost surface of the sample. Particles produced closer to the site of impact tend to be dissociated ions (positive or negative). Secondary particles produced farther from the impact site tend to be molecular compounds, usual fragments of much larger organic macromolecules. The particles are then accelerated into a flight path on their way toward a detector. ToF-SIMS can be performed in either static or dynamic mode. In the static mode the detection limit is in the order of 109 atom cm22, and the mass spectra will contain molecular information of compounds in a few outer monolayers of the surface [78]. In the dynamic mode a much higher ion dose is used, allowing researchers to measure the concentration of different chemical species as a function of depth in a sample. Surface imaging and depth profiling by ToF-SIMS offer both spatial distributions of chemical species on the surface of a sample and depth distribution information. Cheng et al. [79] used ToF-SIMS to differentiate among the surface chemical compositions of the coarse-mode (5.6 10 μm), accumulationmode (0.56 1 μm), and nucleation-mode (0.056 0.1 μm) particles and reported that inorganic salts were the major components on the surfaces of the coarse-mode particles, while long-chain saturated hydrocarbon ions occur in the accumulationmode particles suggesting an aliphatic hydrocarbon-dominated surface, and the nucleation-mode particles contains unsaturated hydrocarbons and aromatic hydrocarbons revealing the possible existence of polycyclic aromatic hydrocarbons or fullerene-like structures on the surfaces. The analysis of aerosols by ToF-SIMS technique can generate a large amount of chemical information, processing of which requires principal component analysis [80].

18.2.2.5 Cavity ringdown spectroscopy Cavity ringdown spectroscopy (CRDS) is a highly sensitive absorption spectroscopy technique with pulsed lasers, which measures absolute optical extinction by samples that scatter and absorb light. CRDS uses a monochromatic laser light source that is focused into a cavity created by the highly reflective mirrors, and the signal is sensed using light transmitted from the mirrors. The advantage of CRDS is the long path length created by the reflective mirrors that increase the sensitivity of the technique and the amount of time that the sample interacts with light. The applicability of CRDS in the measurement of aerosol properties was first demonstrated in 1998 [81]. It is increasingly being applied to study the absorption and scattering

Advanced micro- and nanoscale characterization techniques for carbonaceous aerosols

465

properties of atmospheric aerosols, the contribution of absorption to the total optical extinction coefficient, arising from the complex component of the aerosol refractive index [82 85]. CRDS and its successors have more potential in the study of aerosol optical properties and their spatial and temporal variation, and also it may have possible applications in the studies of visibility, climate forcing by aerosol, and the validation of aerosol retrieval schemes from satellite data [86].

18.2.2.6 Single Particle Soot Photometer Atmosphere BC particles cause adverse health effects and impact the climate, unfortunately, the accurate measurement of their properties and mass concentrations remains difficult. The Single Particle Soot Photometer (SP2) can help in improving this situation by measuring the mass of refractory BC in individual particles as well as its mixing state [87]. The SP2 technique with high sensitivity, fast response, and specificity to EC can directly quantify the BC in individual aerosol particles [88]. It can detect individual BC particles in the mass range of B3 300 fg (B0.15 0.7 μm volume equivalent diameter) [89]. It is used to quantify the size resolute mass concentration of BC from measurements of individual soot particles. It uses laserinduced incandescence and is based on the light-absorbing property of soot. The laser light is absorbed by the particle causing it to incandesce, which is detected by selected optical filters in two different wavelength regions (350 800 and 630 800 nm) and the intensity of the incandescence in these two windows is converted through a series of calculations to BC particle mass. Besides, BC mass determination SP2 can be used to study the soot particle coatings, hygroscopicity, morphology, and mixing state [90 94].

18.3

Summary

The level of scientific understanding as well as advanced level characterization of CAs is essential in order to evaluate their impacts on both human health and climate. Micro- and nanoscale characterizations by using advanced techniques including microscopy and spectroscopy play key role for determining the detailed physical chemical properties and mixing state of CAs in the atmosphere. This chapter discussed the recent micro- and nanolevel advances for characterization of atmospheric CA. This is observed that each technique has their capabilities to measure aerosol properties and can provide information for future research.

References [1] V. Ramanathan, G. Carmichael, Global and regional climate changes due to black carbon, Nat. Geosci. 1 (2008) 121 127. Available from: https://doi.org/10.1038/ngeo156. [2] A.J. Cohen, M. Brauer, R. Burnett, H.R. Anderson, J. Frostad, K. Estep, et al., Estimates and 25-year trends of the global burden of disease attributable to ambient air pollution: an analysis of data from the Global Burden of Diseases Study 2015, Lancet 389 (2017) 1907 1918. Available from: https://doi.org/10.1016/S0140-6736(17)30505-6.

466

Handbook of Nanomaterials in Analytical Chemistry

[3] J.E. Penner, M. Andreae, H. Annegarn, L. Barrie, J. Feichter, D. Hegg, et al., Aerosols, their direct and indirect effects. Climate Change 2001: the scientific basis, Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change., Cambridge University Press, Cambridge, United Kingdom and New York, USA, 2001 (Chapter 5). [4] D. Contini, R. Vecchi, M. Viana, Carbonaceous aerosols in the atmosphere, Atmosphere 9 (5) (2018) 181. Available from: https://doi.org/10.3390/atmos9050181. [5] K.E. Yttri, C.L. Myhre, K. Torseth, The carbonaceous aerosol-a remaining challenge, WMO Bull. 58 (1 January) (2009) 54 60. [6] S.K. Sze, N. Siddique, J.J. Sloan, R. Escribano, Raman spectroscopic characterization of carbonaceous aerosols, Atmos. Environ. 35 (2001) 561 568. [7] P. Sannigrahi, A.P. Sullivan, R.J. Weber, E.D. Ingall, Characterization of water-soluble organic carbon in urban atmospheric aerosols using solid-state 13C NMR spectroscopy, Environ. Sci. Technol. 400 (2006) 666 672. Available from: https://doi.org/10.1021/ es051150i. [8] T.C. Bond, S.J. Doherty, D.W. Fahey, P.M. Forster, T. Berntsen, B.J. DeAngelo, et al., Bounding the role of black carbon in the climate system: a scientific assessment, J. Geophys. Res.: Atmospheres 118 (2013) 5380 5552. Available from: https://doi.org/ 10.1002/jgrd.50171. [9] L.E. Murr, J.J. Bang, E.V. Esquivel, P.A. Guerrero, D.C. Lopez, Carbon nanotubes, nanocrystal forms, and complex nanoparticle aggregates in common fuel-gas combustion sources and the ambient air, J. Nanopart. Res. 6 (2004) 241 251. Available from: https://doi.org/10.1023/B:NANO.0000034651.91325.40. [10] J. Wang, Q. Zhang, M. Chen, S. Collier, S. Zhou, X. Ge, et al., First chemical characterization of refractory black carbon aerosols and associated coatings over the Tibetan plateau (4730 m a.s.l), Environ. Sci. Technol. 51 (2017) 14072 14082. Available from: https://doi.org/10.1021/acs.est.7b03973. [11] J. Zhang, B. Jiang, Z. Wang, Y. Liang, Y. Zhang, C. Xu, et al., Molecular characterisation of ambient aerosols by sequential solvent extractions and high-resolution mass spectrometry, Environ. Chem. 15 (2018) 150 161. Available from: https://doi.org/ 10.1071/EN17197. [12] C. Coury, A.M. Dillner, ATR-FTIR characterization of organic functional groups and inorganic ions in ambient aerosols at a rural site, Atmos. Environ. 43 (2009) 940 948. Available from: https://doi.org/10.1016/j.atmosenv.2008.10.056. [13] R.L. Vander Wal, V.M. Bryg, M.D. Hays, XPS analysis of combustion aerosols for chemical composition, surface chemistry, and carbon chemical state, Anal. Chem. 83 (2011) 1924 1930. Available from: https://doi.org/10.1021/ ac102365s. [14] O. Boucher, D. Randall, P. Artaxo, C. Bretherton, G. Feingold, P. Forster, et al., Clouds and aerosols. Climate Change 2013: the physical science basis, Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change., Cambridge University Press, Cambridge, United Kingdom and New York, USA, 2013 [Chapter 7]. [15] C.M. Long, M.A. Nascarella, P.A. Valberg, Carbon black vs. black carbon and other airborne materials containing elemental carbon: physical and chemical distinctions, Environ. Pollut. 181 (2013) 271 286. Available from: https://doi.org/10.1016/j. envpol.2013.06.009.

Advanced micro- and nanoscale characterization techniques for carbonaceous aerosols

467

[16] D.G. Streets, T.C. Bond, T. Lee, C. Jang, On the future of carbonaceous aerosol emissions, J. Geophys. Res. 109 (D24212) (2004) 1 19. Available from: https://doi.org/ 10.1029/2004JD004902. [17] P. Forster, V. Ramaswamy, P. Artaxo, T. Berntsen, R. Betts, D.W. Fahey, et al., Chapter 2—Changes in atmospheric constituents and in radiative forcing. Climate Change 2007: the Physical Science Basis, in: Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, United Kingdom and New York, USA. [18] M.O. Andreae, P. Merlet, Emission of trace gases and aerosols from biomass burning, Global Biogeochem. Cycles 15 (2001) 955 966. [19] C.E. Chung, V. Ramanathan, D. Decremer, Observationally constrained estimates of carbonaceous aerosol radiative forcing, PNAS 109 (29) (2012) 11624 11629. Available from: https://doi.org/10.1073/pnas.1203707109. [20] C.A. Pope, M.C. Turner, R. Burnett, M. Jerrett, S.M. Gapstur, W.R. Diver, et al., Relationships between fine particulate air pollution, cardiometabolic disorders and cardiovascular mortality, Circ. Research (2014). Available from: https://doi.org/10.1161/ CIRCRESAHA.116.305060. [21] Y. Du, X. Xu, M. Chu, Y. Guo, J. Wang, Air particulate matter and cardiovascular disease: the epidemiological, biomedical and clinical evidence, J. Thoracic Dis. 8 (1) (2016) E8 E19. Available from: https://doi.org/10.3978/j.issn.2072-1439.2015.11.37. [22] J.B. Burkholder, The essential role for laboratory studies in atmospheric chemistry, Environ. Sci. Technol. 51 (2017) 2519 2528. Available from: https://doi.org/10.1021/ acs.est.6b04947. [23] C.M. Hussain (Ed.), Handbook of Nanomaterials for Industrial Applications, Elsevier, 2018. [24] C.M. Hussain (Ed.), Nanomaterials in Chromatography: Current Trends in Chromatographic Research Technology and Techniques, Elsevier, 2018. [25] B.J. Inkson, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) for Materials Characterization, Woodhead Publishing, 2016 (Chapter 2). Available from: https://doi.org/10.1016/B978-0-08-100040-3.00002-X. [26] A.P. Ault, J.L. Axson, Atmospheric aerosol chemistry: spectroscopic and microscopic advances, Anal. Chem. 89 (2017) 430 452. Available from: https://doi.org/10.1021/ acs.analchem.6b04670. [27] G.S. Casuccio, T.L. Lersch, S.F. Schlaegle, D.V. Martello, Characterization of ambient carbonaceous particles using electron microscopy techniques, Fuel Chem. Div. Prepr. 47 (2) (2002) 624 626. [28] S.J. Pennycook, A.R. Lupini, M. Varela, A.Y. Borisevich, Y. Peng, M.P. Oxley, et al., Scanning transmission electron microscopy for nanostructure characterization, Scanning Microscopy for Nanotechnology, Springer, New York, 2007 (Chapter 6). Available from: https://doi.org/10.1007/978-0-387-39620-0_6. [29] H. Yao, K. Kimura, in: A. Me´ndez-Vilas, J. Dı´az (Eds.), Field Emission Scanning Electron Microscopy for Structural Characterization of 3D Gold Nanoparticle Superlattices, Modern Research and Educational Topics in Microscopy, 2007, pp. 568 575. [30] J. Kasparian, E. Frejafon, P. Rambaldi, J. Yu, B. Vezin, J.P. Wolf, et al., Characterization of urban aerosols using SEM-microscopy, X-ray analysis and Lidar measurements, Atmos. Environ. 32 (17) (1998) 2957 2967. [31] J. Li, M. Posfai, P.V. Hobbs, P.R. Buseck, Individual aerosol particles from biomass burning in southern Africa: 2. Compositions and aging of inorganic particles, J.

468

[32] [33] [34]

[35]

[36] [37]

[38]

[39]

[40]

[41]

[42]

[43]

[44]

[45]

[46]

Handbook of Nanomaterials in Analytical Chemistry

Geophys. Res. 108 (D13) (2003) 201 212. Available from: https://doi.org/10.1029/ 2002JD002310. E.D. Dikio, Morphological characterization of soot from the atmospheric combustion of kerosene, E-J. Chem. 8 (3) (2011) 1068 1073. D.N. Shooto, E.D. Dikio, Morphological characterization of soot from the combustion of candle wax, Int. J. Electrochem. Sci. 6 (2011) 1269 1276. Y. Shi, Y. Ji, H. Sun, F. Hui, J. Hu, Y. Wu, et al., Nanoscale characterization of PM2.5 airborne pollutants reveals high adhesiveness and aggregation capability of soot particles, Sci. Rep. 5 (2015) 11232. Available from: https://doi.org/10.1038/srep11232. E. Frejafon, J. Kasparian, P. Rambaldi, J. Yu, B. Vezin, J.P. Wolf, Three-dimensional analysis of urban aerosols by use of a combined lidar, scanning electron microscopy, and x-ray microanalysis, Appl. Opt. 37 (12) (1998) 2231 2237. A.M. Donald, The use of environmental scanning electron microscopy for imaging wet and insulating materials, Nat. Mater. 2 (2003) 511 516. M. Ebert, M. Inerle-Hof, S. Weinbruch, Environmental scanning electron microscopy as a new technique to determine the hygroscopic behaviour of individual aerosol particles, Atmos. Environ. 36 (2002) 5909 5916. Z. Bai, Y. Ji, Y. Pi, K. Yang, L. Wang, Y. Zhang, et al., Hygroscopic analysis of individual Beijing haze aerosol particles by environmental scanning electron microscopy, Atmos. Environ. 172 (2018) 149 156. Available from: https://doi.org/10.1016/j. atmosenv.2017.10.031. F. Zimmermann, M. Ebert, A. Worringen, L. Schutz, S. Weinbruch, Environmental scanning electron microscopy (ESEM) as a new technique to determine the ice nucleation capability of individual atmospheric aerosol particles, Atmos. Environ. 41 (2007) 8219 8227. Available from: https://doi.org/10.1016/j.atmosenv.2007.06.023. D.J. Smith, Ultimate resolution in the electron microscope? Mater. Today (Microsc.) 11 (2008) 30 38. Available from: https://doi.org/10.1016/S1369-7021(09)70005-7 (special issue). C. Kisielowski, B. Freitag, M. Bischoff, H. van Lin, S. Lazar, G. Knippels, et al., Detection of single atoms and buried defects in three dimensions by aberration˚ information limit, Microsc. Microanal. 14 corrected electron microscope with 0.5-A (2008) 469 477. Available from: https://doi.org/10.1017/S1431927608080902. X.F. Zhang, T. Kamino, Imaging gas-solid interactions in an atomic resolution environmental TEM, Microsc. Today 14 (5) (2006) 16 19. Available from: https://doi.org/ 10.1017/S1551929500058600. J. Saikia, B. Narzary, S. Roy, M. Bordoloi, P. Saikia, B.K. Saikia, Nanominerals, fullerene aggregates, and hazardous elements in coal and coal combustion-generated aerosols: an environmental and toxicological assessment, Chemosphere 164 (2016) 84 91. Available from: https://doi.org/10.1016/j.chemosphere.2016.08.086. W. Li, L. Shao, Transmission electron microscopy study of aerosol particles from the brown hazes in northern China, J. Geophys. Res. 114 (2009) D09302. Available from: https://doi.org/10.1029/2008JD011285. H. Geng, S. Kang, H.-J. Jung, M. Choel, H. Kim, C.-U. Ro, Characterization of individual submicrometer aerosol particles collected in Incheon, Korea, by quantitative transmission electron microscopy energy-dispersive X-ray spectrometry, J. Geophys. Res. 115 (2010) D15306. Available from: https://doi.org/10.1029/2009JD013486. K. Adachi, P.R. Buseck, Internally mixed soot, sulfates, and organic matter in aerosol particles from Mexico City, Atmos. Chem. Phys. 8 (2008) 6469 6481. Available from: https://doi.org/10.5194/acp-8-6469-2008.

Advanced micro- and nanoscale characterization techniques for carbonaceous aerosols

469

[47] A.L. Bondy, R.M. Kirpes, R.L. Merzel, K.A. Pratt, M.M.B. Holl, A.P. Ault, Atomic force microscopy-infrared spectroscopy of individual atmospheric aerosol particles: subdiffraction limit vibrational spectroscopy and morphological analysis, Anal. Chem. 89 (2017) 8594 8598. Available from: https://doi.org/10.1021/acs.analchem.7b02381. [48] M. Posfa, H. Xu, J.R. Anderson, P.R. Buseck, Wet and dry sizes of atmospheric aerosol particles: an AFM-TEM study, Geophys. Res. Lett. 25 (11) (1998) 1907 1910. [49] D.W. Lehmpuhl, K.A. Ramirez-Aguilar, A.E. Michel, K.L. Rowlen, J.W. Birks, Physical and chemical characterization of atmospheric aerosols by atomic force microscopy, Anal. Chem. 71 (2) (1999) 379 383. Available from: https://doi.org/10.1021/ ac980849m. [50] G.D. Falco, M. Commodo, P. Minutolo, A. D’Anna, Flame-formed carbon nanoparticles: morphology, interaction forces, and Hamaker constant from AFM, Aerosol Sci. Technol. 49 (2015) 281 289. Available from: https://doi.org/10.1080/ 02786826.2015.1022634. [51] D.T. Allen, E. Palen, Recent advances in aerosol analysis by infrared spectroscopy, J. Aerosol Sci. 20 (4) (1989) 441 455. [52] H. Rosen, T. Novakov, Raman scattering and the characterisation of atmospheric aerosol particles, Nature 266 (21) (1977) 708 710. [53] G. Schweiger, Raman scattering on single aerosol particles and on flowing aerosols: a review, J. Aerosol Sci. 21 (4) (1990) 483 509. [54] A.K.Y. Lee, C.K. Chan, Single particle Raman spectroscopy for investigating atmospheric heterogeneous reactions of organic aerosols, Atmos. Environ. 41 (2007) 4611 4621. Available from: https://doi.org/10.1016/j.atmosenv.2007.03.040. [55] A.K.Y. Lee, T.Y. Ling, C.K. Chan, Understanding hygroscopic growth and phase transformation of aerosols using single particle Raman spectroscopy in an electrodynamic balance, Faraday Discuss. 137 (2008) 245 263. [56] M. Knauer, M. Carrara, D. Rothe, R. Niessner, N.P. Ivleva, Changes in structure and reactivity of soot during oxidation and gasification by oxygen, studied by micro-Raman spectroscopy and temperature programmed oxidation, Aerosol Sci. Technol. 43 (2009) 1 8. Available from: https://doi.org/10.1080/02786820802422250. [57] A. Sadezky, H. Muckenhuber, H. Grothe, R. Niessner, U. Poschl, Raman microspectroscopy of soot and related carbonaceous materials: spectral analysis and structural information, Carbon 43 (2005) 1731 1742. Available from: https://doi.org/10.1016/j. carbon.2005.02.018. [58] N.P. Ivleva, U. McKeon, R. Niessner, U. Poschl, Raman microspectroscopic analysis of size-resolved atmospheric aerosol particle samples collected with an ELPI: soot, humic-like substances, and inorganic compounds, Aerosol Sci. Technol. 41 (7) (2007) 655 671. Available from: https://doi.org/10.1080/02786820701376391. [59] T. Catelani, G. Pratesi, M. Zoppi, Raman characterization of ambient airborne soot and associated mineral phases, Aerosol Sci. Technol. 48 (2014) 13 21. Available from: https://doi.org/10.1080/02786826.2013.847270. [60] S. Mertes, B. Dippel, A. Schwarzenbock, Quantification of graphitic carbon in atmospheric aerosol particles by Raman spectroscopy and first application for the determination of mass absorption efficiencies, Aerosol Sci. 35 (2004) 347 361. Available from: https://doi.org/10.1016/j.jaerosci.2003.10.002. [61] J.D. Rindelaub, R.L. Craig, L. Nandy, A.L. Bondy, C.S. Dutcher, P.B. Shepson, et al., Direct measurement of pH in individual particles via Raman microspectroscopy and variation in acidity with relative humidity, J. Phys. Chem. A 120 (2016) 911 917. Available from: https://doi.org/10.1021/acs.jpca.5b12699.

470

Handbook of Nanomaterials in Analytical Chemistry

[62] J. Ofner, T.D. Gaudig, K.A. Kamilli, A. Held, H. Lohninger, V. Deckert, et al., Tipenhanced Raman spectroscopy of atmospherically relevant aerosol nanoparticles, Anal. Chem. 88 (2016) 9766 9772. Available from: https://doi.org/10.1021/acs. analchem.6b02760. [63] R.L. Craig, A.L. Bondy, A.P. Ault, Surface enhanced Raman spectroscopy enables observations of previously undetectable secondary organic aerosol components at the individual particle level, Anal. Chem. 87 (2015) 7510 7514. Available from: https:// doi.org/10.1021/acs.analchem.5b01507. [64] P. Kulkarni, P.A. Baron, K. Willeke (Eds.), Aerosol Measurement: Principles, Techniques, and Applications, third ed., Wiley & Sons, Hoboken, NJ, 2011. [65] D.T. Allen, E.J. Palen, M.I. Haimov, S.V. Hering, J.R. Young, Fourier transform infrared spectroscopy of aerosol collected in a low pressure impactor (LPI/FTIR): method development and field calibration, Aerosol Sci. Technol. 21 (1994) 325 342. Available from: https://doi.org/10.1080/02786829408959719. [66] H.-J. Jung, H.-J. Eom, H.-W. Kang, M. Moreau, S. Sobanska, C.-U. Ro, Combined use of quantitative ED-EPMA, Raman microspectrometry, and ATR-FTIR imaging techniques for the analysis of individual particles, Analyst 139 (2014) 3949 3960. Available from: https://doi.org/10.1039/c4an00380b. [67] H.-J. Eom, D. Gupta, H.-R. Cho, H.J. Hwang, S.D. Hur, Y. Gim, et al., Single-particle investigation of summertime and wintertime Antarctic sea spray aerosols using low-Z particle EPMA, Raman microspectrometry, and ATR-FTIR imaging techniques, Atmos. Chem. Phys. 16 (2016) 13823 13836. Available from: https://doi.org/10.5194/ acp-16-13823-2016. [68] Y.-C. Song, H.-J. Eom, H.-J. Jung, M.A. Malek, H.K. Kim, H. Geng, et al., Investigation of aged Asian dust particles by the combined use of quantitative EDEPMA and ATR-FTIR imaging, Atmos. Chem. Phys. 13 (2013) 3463 3480. Available from: https://doi.org/10.5194/acp-13-3463-2013. [69] Y.E. Araktingi, N.S. Bhacca, W.G. Proctor, J.W. Robinson, Analysis of airborne particulates by electron spectroscopy for chemical analysis (ESCA), Spectrosc. Lett. 4 (10&11) (1971) 365 376. Available from: https://doi.org/10.1080/ 00387017108064667. [70] J. Toth, I. Beszeda, C.S. Cserhati, F. Medve, XPS and EPMA study of size-fractionated ambient aerosol particles collected in urban and industrial areas, Surf. Interface Anal. 25 (1997) 970 982. [71] B.M. Hutton, D.E. Williams, Assessment of X-ray photoelectron spectroscopy for analysis of particulate pollutants in urban air, Analyst 125 (2000) 1703 1706. Available from: https://doi.org/10.1039/b005872f. [72] J. Song, P. Peng, Surface characterization of aerosol particles in Guangzhou, China: a study by XPS, Aerosol Sci. Technol. 43 (2009) 1230 1242. Available from: https:// doi.org/10.1080/02786820903325394. [73] S. Rella, C. Malitesta, X-ray photoelectron spectroscopy characterization of aerosol particles in Antarctica, Antarct. Sci. 27 (5) (2015) 493 499. Available from: https:// doi.org/10.1017/S0954102015000176. [74] D. Atzei, M. Fantauzzi, A. Rossi, P. Fermo, A. Piazzalunga, G. Valli, et al., Surface chemical characterization of PM10 samples by XPS, Appl. Surf. Sci. 307 (2014) 120 128. Available from: https://doi.org/10.1016/j.apsusc.2014.03.178. [75] N.N. Mustafi, R.R. Raine, B. James, Characterization of exhaust particulates from a dual fuel engine by TGA, XPS, and Raman techniques, Aerosol Sci. Technol. 44 (2010) 954 963. Available from: https://doi.org/10.1080/02786826.2010.503668.

Advanced micro- and nanoscale characterization techniques for carbonaceous aerosols

471

[76] J.W.G. Bentz, J. Goschnick, J. Schuricht, H.J. Ache, J. Zehnpfennig, A. Benninghoven, Analysis and classification of individual outdoor aerosol particles with SIMS time-offlight mass spectrometry, Fresenius J. Anal. Chem. 353 (1995) 603 608. [77] N. Mayama, Y. Miura, K. Misawa, A. Takami, T. Sakamoto, M. Fujii, Characterization of black carbon in fine aerosol particles using high lateral resolution TOF-SIMS, Anal. Sci. 29 (2013) 479 481. [78] R.V. Ham, A. Adriaens, L.V. Vaeck, F. Freddy Adams, The use of time-of-flight static secondary ion mass spectrometry imaging for the molecular characterization of single aerosol surfaces, Anal. Chim. Acta 558 (2006) 115 124. Available from: https://doi. org/10.1016/j.aca.2005.11.041. [79] W. Cheng, L.T. Weng, Y. Li, A. Lau, C. Chan, C.-M. Chan, Characterization of sizesegregated aerosols using ToF-SIMS imaging and depth profiling, Surf. Interface Anal. (2014). Available from: https://doi.org/10.1002/sia.5552 (wileyonlinelibrary.com). [80] C.F. Palma, J. Greg, G.J. Evans, R.N.S. Sodhi, Imaging of aerosols using time of flight secondary ion mass spectrometry, Appl. Surf. Sci. 253 (2007) 5951 5956. Available from: https://doi.org/10.1016/j.apsusc.2006.12.126. [81] A.D. Sappey, E.S. Hill, T. Settersten, M.A. Linne, Fixed-frequency cavity ringdown diagnostic for atmospheric particulate matter, Opt. Lett. 23 (12) (1998) 954 956. [82] M.N. Fiddler, I. Israel Begashaw, M.A. Mickens, M.S. Collingwood, Z. Assefa, S. Bililign, Laser spectroscopy for atmospheric and environmental sensing, Sensors 9 (2009) 10447 10512. Available from: https://doi.org/10.3390/s91210447. [83] D. Mellon, S.J. King, J. Kim, J.P. Reid, A.J. Orr-Ewing, Measurements of extinction by aerosol particles in the near-infrared using continuous wave cavity ring-down spectroscopy, J. Phys. Chem. A 115 (2011) 774 783. Available from: https://doi.org/10.1021/ jp109894x. [84] A.A. Riziq, C. Erlick, E. Dinar, Y. Rudich, Optical properties of absorbing and nonabsorbing aerosols retrieved by cavity ring down (CRD) spectroscopy, Atmos. Chem. Phys. 7 (2007) 1523 1536. [85] T.J.A. Butler, J.L. Miller, A.J. Orr-Ewing, Cavity ring-down spectroscopy measurements of single aerosol particle extinction. I. The effect of position of a particle within the laser beam on extinction, J. Chem. Phys. 126 (2007) 174302-1 174302-7. Available from: https://doi.org/10.1063/1.2723735. [86] A.W. Strawa, R. Castaneda, T. Owano, D.S. Baer, B.A. Paldus, The measurement of aerosol optical properties using continuous wave cavity ring-down techniques, J. Atmos. Oceanic Technol. 20 (2003) 454 465. [87] M. Laborde, M. Schnaiter, C. Linke, H. Saathoff, K.-H. Naumann, O. Mohler, et al., Single Particle Soot Photometer intercomparison at the AIDA chamber, Atmos. Meas. Tech. 5 (2012) 3077 3097. Available from: https://doi.org/10.5194/amt-5-3077-2012. [88] M. Laborde, P. Mertes, P. Zieger, J. Dommen, U. Baltensperger, M. Gysel, Sensitivity of the single particle soot photometer to different black carbon types, Atmos. Meas. Tech. 5 (2012) 1031 1043. Available from: https://doi.org/10.5194/amt-5-1031-2012. [89] J.P. Schwarz, R.S. Gao, D.W. Fahey, D.S. Thomson, L.A. Watts, J.C. Wilson, et al., Single-particle measurements of midlatitude black carbon and light-scattering aerosols from the boundary layer to the lower stratosphere, J. Geophys. Res. 111 (2006) D16207. Available from: https://doi.org/10.1029/2006JD007076. [90] J.P. Schwarz, J.R. Spackman, D.W. Fahey, R.S. Gao, U. Lohmann, P. Stier, et al., Coatings and their enhancement of black carbon light absorption in the tropical atmosphere, J. Geophys. Res. 113 (2008) D03203. Available from: https://doi.org/10.1029/ 2007JD009042.

472

Handbook of Nanomaterials in Analytical Chemistry

[91] A.R. Metcalf, C.L. Loza, M.M. Coggon, J.S. Craven, H.H. Jonsson, R.C. Flagan, et al., Secondary organic aerosol coating formation and evaporation: chamber studies using black carbon seed aerosol and the single-particle soot photometer, Aerosol Sci. Technol. 47 (2013) 326 347. Available from: https://doi.org/10.1080/ 02786826.2012.750712. [92] A.J. Sedlacek, E.R. Lewis, B. Timothy, T.B. Onasch, A.T. Lambe, P. Davidovits, Investigation of refractory black carbon-containing particle morphologies using the single-particle soot photometer (SP2), Aerosol Sci. Technol. 49 (2015) 872 885. Available from: https://doi.org/10.1080/02786826.2015.1074978. [93] N. Moteki, Y. Kondo, K. Adachi, Identification by single-particle soot photometer of black carbon particles attached to other particles: laboratory experiments and ground observations in Tokyo, J. Geophys. Res.: Atmospheres 119 (2014) 1031 1043. Available from: https://doi.org/10.1002/2013JD020655. [94] Q. Wang, R.-J. Huang, J. Cao, Y. Han, G. Wang, G. Li, Mixing state of black carbon aerosol in a heavily polluted urban area of China: implications for light absorption enhancement, Aerosol Sci. Technol. 48 (2014) 689 697. Available from: https://doi. org/10.1080/02786826.2014.917758.

Issues related with the analysis of nanomaterials

19

Christine Vauthier Institut Galien Paris-Sud, UMR CNRS 8612, University Paris-Sud, Chatenay-Malabry Cedex, France

Abbreviations AFM atomic force microscopy Cryo-TEM cryo-transmission electron microscopy DLS dynamic light scattering ELS PALS electrophoresis light scattering coupled with phase analysis light scattering EU-NCL European Nanomedicine Characterization Laboratory FFF Field flow fractionation FT-IR Fourier transform infrared spectroscopy ISO International Standardization Organization NIH-NCL National Institute of Health—Nanomedicine Characterization Laboratory NIST National Institute of Standard and Technology NTA nanoparticle tracking analysis SEM scanning electron microscopy TEM transmission electron microscopy TRPS tunable resistive pulse sensing

19.1

Introduction

Nanomaterials comprise objects that have external size of at least one dimension under 100 nm ( see definition in [1]). They are materials built from the assembly of many molecules that can be identical or of different nature. Because of their very small size, highly developed specific surface area is the seat for an intense interfacial reactivity, which is not found in the same materials occurring at a larger size that exposed a much smaller specific surface area to the surrounding media. Thanks to their very small size, nanomaterials display unique properties that differ from those found on material of the same composition occurring in bulk. They interest many fields of the industry [2,3], in analytical science [4], and are considered for applications in medicines [5 9]. Properties, functionality, and activity of nanomaterials closely depend on their chemical nature and physical attributes. As for all manufactured products, quality and safety of use require strict quality control analysis. The chemical composition Handbook of Nanomaterials in Analytical Chemistry. DOI: https://doi.org/10.1016/B978-0-12-816699-4.00019-0 Copyright © 2020 Elsevier Inc. All rights reserved.

474

Handbook of Nanomaterials in Analytical Chemistry

can be accessed with analytical techniques generally used to analyze other materials. In contrast, analysis of physical attributes of nanomaterials is more difficult to achieve due to the small size and requires the development of specific analytical methods. In addition, nanomaterials generally occur as a population of individual nanoobjects. In the ideal case, the population is composed of perfectly identical nanoobjects. However, very few engineering methods are suitable to produce such “ideal” nanomaterials. In general, they are composed of individual nanoobjects, each having its own characteristics that can differ more or less from that of the mean value found for the population. Deviation from the mean value of key attributes may significantly influence the performance of the nanoobject in the framework of its intended use. So, the distribution of the population around the mean value of key attributes is an important characteristic to determine too. In this context, it is noteworthy that even accurate evaluations of the size and size distribution of a nanomaterial, which are obvious attributes to determine, are challenging tasks [10 14]. Artifacts may also contribute to the misinterpretation of the measurement results hence to draw incorrect conclusions with possible impact evaluating potential hazards of nanomaterials [15]. At present, very few nanomaterial attributes can be evaluated in routine. These include general attributes such as the size, size distribution, and surface charges through the evaluation of their zeta potential. Several affordable instruments to achieve their measurements are available on the market. Morphology, which is another general attribute of nanomaterials, can be determined by electron microscopy or using atomic force microscopy (AFM). These techniques provide images of nanomaterials and can be found on technological platforms in universities and in some private analytical laboratories. Attributes that are more closely linked with functionalities exploited in the application of the nanomaterial are more challenging to evaluate. Their determination is often pending to the application of analytical methods used in research. Today, the low number of methods of characterization of nanomaterials that can be applied in routine considerably limits the number of attributes evaluated during quality control assessment of nanomaterials. This is an issue for the development of such materials and especially for nanomedicines, safety and activity of which cannot be evaluated confidently only from their measurable general attributes as pointed out in several recent papers [16 20]. The objective of this chapter was to review and discuss the present state of the art on the analysis of physical attributes of nanomaterials. A first part attempts to list the different attributes that may be used to characterize nanomaterials in relation with their intended applications. The second part points out the few attributes that can be determined in routine, thanks to the existence of suitable marketed measurement instruments. This part of the chapter will also examine the stage of the standardization and remaining analytical issues. In the last part, the evaluation of other attributes will be considered based on techniques applied in research or methods that are used to characterize non-nanomaterials. From a few examples, problems that may arise using

Issues related with the analysis of nanomaterials

475

techniques not specifically designed for the characterization of nanomaterials will be discussed. While this chapter attempts to discuss issues related with the analysis of nanomaterials in general, specific examples were drawn from the characterization of nanomedicines designed for a use in human clinics.

19.2

Nanomaterial characteristics: identifying key attributes

Nanomaterials can be described by different physical attributes. The size is the more obvious parameter. It is generally systematically included within the set of characterization performed in quality control. The size distribution and the morphology are other parameters that are evaluated during development stages of products and that can be included in quality control as a mean to check the reproducibility of the manufacturing process. Depending on the application, nanomaterials are designed to achieve a well-define function that depends on specific attributes. Those for which variations beyond certain limits can compromise the functionality of the nanomaterial are identified as key attributes and carefully considered in procedures dedicated to insure the quality and safety of the product. Key attributes are defined on a case-by-case basis for each nanomaterial consistently with the intended use. Applications in the domain of medicine include a wide range of nanomaterials developed for therapeutic and/or diagnostic purposes [2,3,21]. Their use can differ from their composition and structures, a lot depending on the specific application they are designed for [3,22]. Several nanomedicines are being used in vivo, and their hazard evaluation is an issue for their translation into the clinic. Although characterizations are generally closely related with the intended use, as pharmaceutics or medical devices, the product needs to comply with stringent legislative frameworks (see for instance [23]). Different aspects are taken into consideration including the characterization of their physicochemical attributes with specific requirements due to the small size of nanoobjects composing nanomedicines. Characterizing nanomaterials entering the composition of nanomedicines remains challenging on different levels [10,14,20]. At first, there is a large number of ways by which nanomedicines can be used as a nanomedicine. For each application, there is a need to elucidate how the nanomedicine is interacting with the biological environment to achieve an optimal control of their activity identifying corresponding key attributes of the nanomaterial. Then, our present knowledge for a safe evaluation and supervision of nanomedicines remains partial. Critical attributes that control the pharmacological activity in vivo are not fully elucidated even in the more general cases, considering nanomedicines designed to be administered by the oral or intravenous routes [24,25]. This hampers the definition of a set of

476

Handbook of Nanomaterials in Analytical Chemistry

relevant key attributes for the given type of applications. Besides, nanomedicines occurred in a wide range of compositions and structures, including quite complex structures that improve the difficulty to establish general rules to perform their characterization [22]. Finally, methods are still severely missing to evaluate several of the key attributes of nanomedicines that would be worth to determine in routine [26]. In this context, a consensus was established, identifying a minimum of physical attributes that need to be determined for a nanomedicine that includes the size and size distribution [27]. In addition to size characteristics the morphology and surface charge of the nanomaterials are generally evaluated too as these attributes are also known to impact safety and clinical manifestations of many nanomedicines designed to be administered by the intravenous route [20]. These are also attributes that influence the in vivo fate of nanomedicines delivered by a mucosal route including the oral route [25]. Other characteristics may be required, but their determination is generally demanding and may even be problematic as there is no existing easy method to perform the analysis. For instance, a precise characterization of the surface of nanomedicines intended to be used by the intravenous route would be justified because pharmacology and toxicity of the products is closely controlled by subtle characteristics of the nanoparticle surface including the density and conformation of the chains of hydrophilic macromolecules grafted on the surface of the nanoparticle core [19]. Consistently, parameters such as the surface coating coverage, the topology, and the deformability were included in the list of parameters that may be of interest to consider while developing nanomedicine in a document proposed by the Food and Drug Administration of the United States of the America (see Ref. [29]). However, these parameters are rarely determined as suitable methods for their determinations are not available. The characterization of nanomedicine should also include an evaluation of the stability of the dispersion [20,27]. The stability can be considered on the chemical view point but must also evaluate any possible changes occurring in the structure of the nanomaterial and at the level of the dispersion. As already mentioned, the chemical nature of the nanomedicines can be evaluated through general methods applied in analytical chemistry. Evaluation of the stability of the dispersion can be performed measuring the size of the particles and evaluating the size distribution at different times upon storage. Changes in these characteristics would suggest that the colloidal stability of the dispersion was affected during storage. An increase in the size and size distribution would indicate an aggregation of the nanoparticles, while a decrease in the size would suggest a degradation of the particles. Deciphering the structure of a nanomaterial is demanding and requires very specific methods and the expertise of seasoned scientists. Demonstrating that the structure of the nanomaterial is not affected upon storage will be the most difficult task to achieve analyzing the stability of a nanomedicine. This aspect is eventually considered during early preclinical development stages of a nanomedicine. The following parts give an overview of the different methods applied for the analysis of several attributes of nanomaterials.

Issues related with the analysis of nanomaterials

19.3

477

Analyzing nanomaterial physical attributes with automated and standardized methods

19.3.1 Standardization of methods for the analysis of nanomaterials Standardization in the domain of nanomaterial is a young area. The result of a search with the term “nanomaterial” on the website of the International Standardization Organization (ISO) has mentioned 40 documents defining terms and definitions and 82 standards including technical reports and specifications [30]. Most standards are very recent. The number of the standards drops down to 61 while using the words: “nanomaterial,” “method,” “characterization” in the search engine of the ISO website, and very few were directly devoted to the determination of nanomaterial physical attributes (Table 19.1). Analyzing physical attributes of nanomaterials is pending to the existence of methods that have reached an enough degree of maturity making possible the development of a standardization. As for any kind of analysis, standards are needed to provide reliable measurements being trusted and accepted internationally. Then, applications of measurement methods are pending to the availability of affordable instruments. The nanometrology is a subfield of metrology that emerged to cover the science of measurements dedicated at the nanoscale. It was introduced to answer urgent needs for performing measurement at this size scale concomitantly with the expansion of industrial applications and processes involving nanomaterials that required evaluation methods to bring these nanotechnology-based products safely into the market place. Issues are remaining to develop standardized methods, and standard operating protocols are needed to produce reliable measurements with internationally recognized methods. Efforts in standardization are also needed to develop suitable reference materials, methods, and corresponding instruments. Currently, very few standards have been established to achieve the characterization of nanomaterials ([31], See Table 19.1 for reference of ISO standards). They were developed to achieve measurements of the size by scanning electron microscopy (SEM), dynamic light scattering (DLS), tunable resistive pulse sensing (TRPS), particle tracking analysis (PTA), asymmetrical-flow centrifugal field-flow fractionation (FFF), size distribution by SEM, and zeta potential by acoustic and optical methods. These attributes can be determined with automated instruments. The morphology is another parameter for which a standard has been established using SEM, but no automated procedures have been yet developed, and analysis of images remains mostly manual and greatly depends on the quality of the images produced from the techniques. A general ISO standard explains methods for the analysis of images analyzing the size of particles (see Table 19.1). The Nanomedicine Characterization Laboratory (NCL) created by the National Institute of Health (NIH-NCL) in Frederik, MD, the United States, in the early 2000s was settled to support clinical development of nanomedicines with the mission to provide with resources and

478

Handbook of Nanomaterials in Analytical Chemistry

Table 19.1 International Standardization Organization (ISO) standards for the characterization of nanomaterials. General

Size

Morphology/ Shape/Structure

Surface

ISO 5725-1:1994: Accuracy (trueness and precision) of measurement methods and results—Part 1: General principles and definitions ISO 5725-3:1994: Accuracy (trueness and precision) of measurements methods and results—Part 3: Intermediate measures of the precision of a standard measurement method. ISO Guide 35:2006: Reference materials—General and statistical principles for certification ISO/TS 12805:2011(en): Nanotechnologies—Materials specifications—Guidance on specifying nanoobjects ISO/TR 13014:2012(en): Nanotechnologies—Guidance on physicochemical characterization of engineered nanoscale materials for toxicologic assessment ISO/TR 13329:2012: Nanomaterials—Preparation of material safety data sheet (MSDS) ISO/TS 20477:2017: Nanotechnologies—Standard terms and their definition for cellulose nanomaterial ISO 13322-1:2004: Particle size analysis—Image analysis methods —Part 1: Static image analysis, methods ISO/DIS 19749(en): Nanotechnologies—Measurements of particle size and shape distributions by scanning electron microscopy ISO 22412:2017(en): Particle size analysis—Dynamic light scattering (DLS) ISO 19430:2016(en): Particle size analysis—Particle tracking analysis (PTA) method ISO/TS 21362:2018(en): Nanotechnologies—Analysis of nanoobjects using asymmetrical-flow and centrifugal field-flow fractionation ISO/TS 10797:2012(en): Nanotechnologies—Characterization of single-wall carbon nanotubes using transmission electron microscopy ISO/TS 10798:2011(en): Nanotechnologies—Characterization of single-wall carbon nanotubes using scanning electron microscopy and energy dispersive X-ray spectrometry analysis ISO 13099-1:2012(E): Colloidal systems—Methods for zetapotential determination—Part 1: Electroacoustic and electrokinetic phenomena ISO 13099-2:2012(E): Colloidal systems—Methods for zetapotential determination-Part 2: Optical methods. ISO 13099-3:2012(E): Colloidal systems—Methods for zetapotential determination—Part 3: Acoustic methods ISO/TS 14101:2012(en): Surface characterization of gold nanoparticles for nanomaterial-specific toxicity screening: FT-IR method ISO/TR 19997:2018(en): Guidelines for good practices in zeta-potential measurement

TR, Technical report; TS, technical specification, FT-IR Fourier transform infrared spectroscopy.

Issues related with the analysis of nanomaterials

479

characterization services (NIH-NCL). It is a major player in the development of assay cascades and standard operating conditions for the characterization of physical attributes of nanomaterials composing nanomedicines. The NIH-NCL have published several measurement protocols that are available on its website (NIH-NCL assay cascade [32,33]). A similar service is provided by the European NCL (EU-NCL) built in partnership with the NIH-NCL in the 2010s (EU-NCL, EU-NCL assay cascade [34,35]). Different methods with corresponding automated measurement instruments can be used to determine the size and zeta potential of nanomaterials. The methods are generally indirect, meaning that the measurand is not the measured parameter. The measurand is deduced from the measured parameter from the application of an appropriate model. Thus values found for the evaluated attribute generally depend on the measurement method. For instance, most methods applied to determine the size of nanomaterial dispersed in an aqueous media provide with a hydrodynamic radius/diameter of the particles, which corresponds to the diameter/radius of the particles with a layer of hydration (Fig. 19.1A). The hydrodynamic diameter is deduced from the diffusion coefficient of the particles, which is the measured parameter of the Brownian motion. The mean size and size distribution provided from measurements performed by DLS methods are expressed based on the intensity of the signal collected by the photon detector. It may differ from that deduced from the TRPS method that evaluates the size of particles by measuring an electric pulse, intensity of which is proportional to the volume of electrolyte displaced by a single particle moving through a pore of calibrated volume assuming that the displaced volume of the electrolyte corresponds to that of the particle. With this latter method the evaluation of the size distribution is provided in number. The PTA method also provides with a size distribution in number. As the different methods are given different information about the size and size distribution of nanomaterials, procedures intended to validate measurement protocols and to qualify measurement instruments should be done with standards certified for the method applied by the

Figure 19.1 Attributes versus measurands: (A) size and (B) surface charge.

480

Handbook of Nanomaterials in Analytical Chemistry

measurement instrument to be used. Several National Institute of Standard and Technology (NIST) traceable particle size standards with different sizes and chemical natures are available. Most of them are certified by electron microscopy which is a direct method for the determination of the size and only few are available with a DLS certification. Efforts are ongoing to extend the range of standards certified by the different size measurement methods. Regarding the validation of measurement protocols, procedures to perform such validation have not yet been described in ISO standards. However, procedures to validate protocols of size measurements by DLS and of evaluation of the zeta potential of nanomaterials by electrophoresis light scattering coupled with phase analysis light scattering (ELS PALS) were published in the literature a few years ago [12,36 38]. The International Council on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use was followed as much as possible to achieve these validations, but some adaptations were needed to take into account that methods of characterization of nanomaterials did not require a calibration in contrast to the methods being the subject of this text. Robustness, precision, and trueness of protocols were demonstrated using standard materials and following recommendations of the Guide to the expression of uncertainty in measurement [39]. Those included NIST standards of different sizes that were used to validate the proposed size measurement protocol [12,36]. NIST standards of positive value and reference material of negative value were used to validate the proposed protocol evaluating zeta potential [37]. A procedure to transfer the validated protocols has also been reported [40].

19.3.2 Analyzing the size of nanomaterials Size of nanomaterials can be evaluated by different methods using automated instruments. The DLS is the most widely used method. First automated instruments appeared in the mid-1980s. Instruments working on new methodologies were introduced during the last 10 years. They are based on TRPS, nanoparticle tracking analysis (NTA), centrifugation, and FFF. The DLS method is a batch method meaning that it analyzes the dispersion in its all. TRPS and NTA are performing measurements on each particle composing the sample. Methods based on centrifugation and FFF separate particles according to their size prior to measure their size. Analyzing the size of a nanomaterial remains challenging even with the well-established DLS method. This was revealed for instance in interlaboratory comparisons [41]. It also appears comparing size measurements performed with different DLS instruments [13,42]. Applying known precautions to perform measurements, results of size measurements of a sample of nanomaterial composed of nanoobjects of homogenous size with narrow size distribution are generally accurate and precise [12,36]. In contrast, their application to the characterization of polydisperse nanomaterials is problematic. The intensity of the scattered light is dominated by the larger particles contained in the sample; the signal due to the smaller particles can be partially or totally hindered, making their detection difficult. This is a well-known limitation of DLS methods. Improvements have been

Issues related with the analysis of nanomaterials

481

implemented in the youngest generation of instruments, but size measurements performed on a highly polydisperse dispersion remains problematic [12,13]. More generally, results provided by DLS instruments may be different from those obtained from other measurement methods [11,13,42,43]. Prior selecting DLS as sole technique to measure the size of a given nanomaterial, it is recommended to perform measurements with at least two methods working on different principles including one method based on particle by particle analysis (TRPS, NTA) or including a separation method (analytic centrifugation, FFF) [12,13,42] (Gioria et al., 2018). This shows that even the characterization of a very basic attribute such as the size of nanomaterials is complicated. It requires a thorough investigation based on the use of several techniques that are needed to perform an accurate evaluation of the polydispersity of the sample and obtain relevant information about the size of the nanoobjects composing a sample.

19.3.3 Analyzing zeta potential of nanomaterials The second attribute of nanomaterials for which standards have been established is the determination of the zeta potential (see Table 19.1 for ISO standard reference). Very few reference materials are available yet. They were used for the validation of a measurement protocol by ELS PALS [37]. The zeta potential gives indications about the surface charge of nanomaterial. The charge at the surface of the nanomaterial is a difficult parameter to evaluate in contrast to the zeta potential that corresponds to the charges at the slipping plan between charges associated with the particles and charges from the bulk of the dispersion medium (Fig. 19.1B). The value greatly depends on the nature of the dispersing medium and concentration in electrolytes. This information is needed while giving the result. The easiest methods evaluating the zeta potential of a nanomaterial are indirect based on the measurement of the electrophoretic mobility of the particles. Then, the zeta potential is calculated from this parameter using appropriate models. Affordable instruments are available to evaluate zeta potential of nanomaterials which is the only attribute characterizing the surface properties of nanomaterials that can be currently determined in routine. The instruments are quite automatous, but their applications require precautions to achieve relevant measures. The value obtained is only valid within the framework of the experimental conditions used during determination.

19.4

Analyzing attributes of nanomaterials using other methods

Lists of physical parameters recommended to be included to describe nanomaterials have been drawn in ISO/TR 13329:2012 (see Table 19.1) and by different government agencies [44 46]. In general, they all include the particle size, size distribution, aggregation, and/or agglomeration state, a description of the particle

482

Handbook of Nanomaterials in Analytical Chemistry

shape. Depending on applications and chemical natures, other attributes are requested such as the crystallinity, the dispersibility, the dustiness, and attributes related to the surface of the nanomaterials including the specific surface area (see ISO/TR 13329:2012 in Table 19.1). Sometimes the porosity is included in the list of parameters to evaluate. The stability in terms of the maintenance of the colloidal stage is requested depending on the application envisaged. For nanomedicines the colloidal and chemical stability are important attributes to consider, and more surface characteristics are requested. On a systematic basis, the surface charge needs to be provided. Recent results from the evaluation of nanomedicines have suggested that a more precise characterization of the surface attribute is needed to insure the reproducible in vivo fate of nanomaterials. Indeed, it was shown that small changes in subtle characteristics can generate a significant modification of the interactions between the nanomaterial and biological systems [17,19,28] hence can modify the biodistribution and in turn greatly influence the activity and safety of the nanomedicine. Thus, parameters including the surface coverage, the topology, the configuration of the chains and the deformability of the surface were recently pointed out as possible characteristics to take into consideration as key surface attributes to insure in vivo safety and activity of nanomedicines. As discussed earlier, little standardized methods were developed so far and only general attributes can be analyzed with automated methods applicable in routine. No method and easy to use instrument allowing convenient batch or lot quality evaluation are available to determine other attributes. Three situations can be distinguished. In the first case, a method exists, but its application is tedious and have not been the subject of a standardization yet. This situation is found for the determination of the particle shape. In the second situation, methods applied for the characterization of other materials are used to characterize nanomaterials, although measurement conditions are not ideal. The approach is generally used to characterize the porosity and of the crystallinity of nanomaterials. In the last situation, no easy methods can be applied to access other nanomaterial attributes. The characterization of the intimate structure of nanomaterials can be achieved using methods applied in research. The characterization of the surface of nanomaterials remains unsatisfied. Recently, a few initiatives have been taken to develop appropriate methods as explained bellow.

19.4.1 Evaluating the shape of nanomaterials The shape of nanomaterial can be evaluated by appropriate microscopy methods. This can be done by the direct analysis of images produced during observations of samples by transmission electron microscopy (TEM), SEM, or AFM. An aspect ratio was defined to quantify the shape of the observed nanoobjects. It is deduced from the ratio between the longest and shortest axis measured in two directions on the obtained 2D images of nanoobjects and differed from one when particles have a nonspherical or nondisc shape. To differentiate discs from spheres, 3D images are needed using SEM or AFM. The high of particles can be measured by AFM, which allows measurements in the three dimensions of the space. As for measuring the

Issues related with the analysis of nanomaterials

483

size and size distribution of a sample, it is required to determine the aspect ratio of a large number of particles to perform relevant measurements. To the knowledge of the author, there are no image analyzers that can perform such an analysis that remains to be done manually. The general ISO standard describing the particle size analysis by image analysis methods can be used and that of the measurements of the particle size and shape distribution by SEM (see ISO/DIS19749 and ISO 133221:2004 in Table 19.1).

19.4.2 Evaluating the porosity and crystallinity with general methods for the characterization of materials In the absence of specific methods, the porosity and crystallinity of nanomaterials are often evaluated using existing methods applied for the characterization of nonnanomaterials. These methods analyses dried powders. Thus, prior to performing the analysis, nanomaterials need to be dried. The obtained dry powder contains grains formed by an agglomerate of the nanoobjects composing the nanomaterial. Conditions for the evaluation of the porosity and crystallinity of the nanomaterials are not ideal as bias can be produced due to the arrangement of the nanoobjects in the grains of the powder (Fig. 19.2A). Pores can be formed between particles and may be encountered during the measurement of the porosity of the nanomaterial, and crystalline arrangement of particles in the powder can produce diffraction peaks while investigating the crystallinity of the nanomaterials (Fig. 19.2B). Samples of materials are very different between those included nanomaterials and those found while analyzing materials occurring as monolith. Cautious interpretation of data produced by these methods is then needed, while they are applied to the characterization of nanomaterials.

19.4.3 Analysis of the intimate structure of nanomaterials The analysis of the intimate structure of nanomaterials needs tremendous means implemented in synchrotrons and neutron scattering facilities. X-rays and neutron scattering methods are suitable to decipher the arrangement of components within the structures of nanoobjects [47 49]. In the nanomedicine domain, having access of these information may be useful to understand mechanisms of drug-releasing property of the nanomaterial composing the pharmaceutical product. Highresolution cryo-TEMs would also be suitable techniques, but it has not been so much applied on the characterization of nanomaterials so far [50 52]. Cryo-TEM techniques are quite young methods and were initially developed for the analysis of biological materials including biomolecules and viruses using the high-resolution mode [53 55]. Currently, improvement of techniques continues and their application to the characterization of nanomaterial follows the evolution. Analysis of the intimate structure of nanomaterials remains an obstacle requiring rare instruments and the high expertise of season scientists.

484

Handbook of Nanomaterials in Analytical Chemistry

Figure 19.2 Possible bias evaluating nanoparticle attributes with methods not specifically developed for nanomaterials. (A) Determination of the porosity: spaces between nanoparticles marked in white may represent a significant contribution to the porosity due to the small size of the nanomaterials contained in the dry powder of nanoparticles that is prepared to perform the analysis. (B) SEM picture of polymer nanoparticles showing a crystalline order in the arrangement of the nanoparticles. This type of crystalline arrangement of the nanoparticles within the dry sample prepared for X-ray diffraction analysis can produce diffraction signals on X-ray diffractograms. SEM, Scanning electron microscopy.

19.4.4 Thorough analysis of nanomaterial surface attributes Thorough analysis of nanomaterial surface remains challenging while surface properties beyond surface charge are often key parameters for the functionality of the particles [56]. For instance, in the case of nanomedicines, attributes describing their surface characteristics are other parameters that play a major role to achieve the desired activity and safety of use. They control the biodistribution, cell internalization, and interactions with biological molecules such as proteins in biological fluids and glycoproteins of the mucus on mucosa. Nanomedicines are nanomaterials that are to be introduced in the body intentionally. Establishing the link between surface attribute and biodistribution and activity is important to insure the quality and safety of the pharmaceutical product. With other manufactured nanomaterials which may be introduced in the body accidently, knowing such link would be worth to

Issues related with the analysis of nanomaterials

485

anticipate possible hazard. Currently, the only “easy” way of assessing surface property of nanomaterial is evaluating the zeta potential (see Section 19.3.3 of this chapter). The atomic composition of the surface can be analyzed by X-ray photo-electron spectroscopy. This method requires a specific instrumentation and a high level of expertise for the interpretation of the data while commonly applied in material science. The lateral resolution of the method is of the order of the micrometer and the depth of analysis is of a few nanometers (1 3) on metal surfaces, but considering polymers, the depth of analysis can reach 6 7 nm [57,58]. Spectra obtained from the analysis of the surface of materials composed of polymers may include signals from chemicals composing the underlying surface. The method was applied to analyze surface composition of polymer nanoparticles composing nanomedicines [56,59,60]. More specifically, it was used to demonstrate the presence of poly(ethylene glycol) or its absence on nanoparticle surfaces (see for instance [61]). This polymer was added on the surface of nanomedicines to reduce interactions with blood proteins that extend the time of residence of the nanoparticles in the bloodstream allowing to modulate the in vivo fate of the nanoparticles administered by the intravenous route [23,62]. Besides surface composition the activity of a nanomedicine also depends on the fine-tune of the density, distribution, and conformation of the hydrophilic polymers added on the nanoparticle surface to control their interactions with biological systems, hence the activity. In addition, these characteristics influence the safety as they control the reactivity of undesired biochemical reactions as well as organs in which nanomedicines accumulate in vivo. Evaluating of such subtle surface attributes of nanomedicines requires methods performing analysis at the molecular level. Such methods are currently missing. Existing methods analyze biological activities produced by the response of a biological system confronted to nanomaterials. For instance, they evaluate the response of the complement system, which is a biochemical cascade of the innate immune system found in the plasma (NIH-NCL assay cascade, [18]). Others are based on the evaluation of the cytotoxicity of nanomaterials on define cell lines. Without possibility to characterize better surface attributes of nanomaterials, no correlation can be drawn between nanoparticle characteristics and the induced desired or unwanted biological responses. No progress in the understanding of this relation would be possible hampering rational design of nanomedicines and anticipation of eventual hazards from their physical attributes. Very recently, approaches were suggested based on the evaluation of the accessibility of the nanoparticle surface to proteins. In these approaches, proteins are used as molecular probes allowing to explore the particle surface at a molecular scale. The nature of the molecular probes is consistent with components of biological fluids which interact with nanomaterials entering the body. In one of the proposed methods, fluorescent proteins were used to assess the amount of the nanomaterial surface accessible for protein adsorption [63]. Another method using native proteins of different molecular weight could separate a series of nanoparticles in two groups consistently with steric hindrance properties of the surface coverage expected for the different nanoparticles included in the study. The observed responses resulted from the combined effect of the density of coverage and conformation of polysaccharide chains grafted on the

486

Handbook of Nanomaterials in Analytical Chemistry

nanoparticle surface [64]. Both methods were conceived to be implemented for a routine application in quality control. More works are now requested to test the sensitivity of these methods considering more nanomaterials and to investigate whether the obtained data are relevant enough to insure the quality of nanomedicines based on the measured parameter. A difficulty to perform such evaluation is the absence of standard and/or reference materials. Besides, there is still no method to evaluate the topology and the deformability of nanoparticle surfaces, while these attributes have been identified as other critical attributes for the activity and safety of nanomedicines.

19.5

Conclusion

Analyzing nanomaterials remains a challenge due to the small size of nanoobjects that composed such materials. The characterization and analysis of physical attributes of nanomaterials requires specific methods. At present, only very few general attributes can be analyzed by standardized methods. Affordable automated instruments can be used to evaluate the size, polydispersity, and surface charge choosing suitable method depending on the sample characteristics such as its polydispersity and chemical composition. A tremendous need of accessible measurement methods analyzing attributes that define activity and safety of nanomaterials was pointed out. There are several issues including the lack of methods applicable in quality control, the lack of standard and reference materials to qualify measurement protocols and instruments, the lack of standardized methods, and the lack of methods. Works are on the way to fill the gaps and resolve the analytical needs of products composed of nanomaterials to insure their quality and safety.

References [1] Nanomaterial definitions, ,ec.europa.eu/environment/chemicals/nanotech/faq/definition_en.htm. (accessed 24.01.19); ,www.fda.gov/RegulatoryInformation/Guidances/ ucm257698.htm. (accessed 24.01.19); ISO/TR 18401:2017(en), Nanotechnologies— plain language explanation of selected terms from the ISO/IEC 80004 series, ,www.iso. org/obp/ui/#iso:std:iso:tr:18401:ed-1:v1:en. (accessed 24.01.19). [2] A. Singer, E. Markoutsa, A. Limayem, et al., Nanobiotechnology medical applications: overcoming challenges through innovation, EuroBiotech J. 2 (2018) 146 160. [3] M. Thirumavalavan, K. Settu, J.F. Lee, A short review on applications of nanomaterials in biotechnology and pharmacology, Curr. Bionanotechnol. 2 (2016) 116 121. [4] C.M. Hussain (Ed.), Nanomaterials in Chromatography: Current Trends in Chromatographic Research Technology and Techniques, Elsevier, 2018. Available from: https://doi.org/10.1016/C2016-0-04157-8. [5] R. Juliano, The delivery of therapeutic oligonucleotides, Nucleic Acids Res. 44 (2016) 6518 6548.

Issues related with the analysis of nanomaterials

487

[6] L. Lamch, A. Pucek, J. Kulbacka, et al., Recent progress in the engineering of multifunctional colloidal nanoparticles for enhanced photodynamic therapy and bioimaging, Adv. Colloid Interface Sci. 261 (2018) 62 81. [7] S. Mura, P. Couvreur (Eds.), Nanoteranostic for Personalized Medicine, World Scientific, Location, 2016. Available from: https://doi.org/10.1142/9741. [8] B. Pelaz, C. Alexiou, R. Alvarez-Puebla, et al., Diverse applications of nanomedicine, ACS Nano 11 (2017) 2313 2381. [9] C.L. Ventola, Progress in nanomedicine: approved and investigational nanodrugs, P T 42 (2017) 742 755. [10] R.M. Christ, J. Hall Grossman, A.K. Patri, Common pitfalls in nanotechnology: lessons learned from NCI’s Nanotechnology Characterization Laboratory, Integr. Biol. (Camb.) 5 (2013). Available from: https://doi.org/10.1039/c2ib20117h. [11] W. Anderson, D. Kozak, V.A. Coleman, et al., A comparative study of submicron particle sizing platforms: accuracy, precision and resolution analysis of polydisperse particle size distributions, J. Colloid Interface Sci. 405 (2013) 322 330. [12] F. Varenne, J. Botton, M. Merlet, et al., Size of monodispersed nanomaterials evaluated by dynamic light scattering: protocol validated for measurements of 60 and 203 nm diameter nanomaterials is now extended to 100 and 400 nm, Int. J. Pharm. 515 (2016) 245 253. [13] F. Varenne, A. Makky, M. Gaucher-Delmas, et al., Multimodal dispersion of nanoparticles: a comprehensive evaluation of size distribution with 9 size measurement methods, Pharm. Res. 33 (2016) 1220 1234. [14] J.D. Clogston, R.M. Crist, S.E. McNeil, Physicochemical characterization of polymer nanoparticles: challenges and present limitations, in: C. Vauthier, G. Ponchel (Eds.), Polymer Nanoparticles for Nanomedicines, Springer International Publishing, Cham, Switzerland, 2016, pp. 187 203. [15] E.J. Petersen, T.B. Henry, J. Zhao, et al., Identification and avoidance of potential artifacts and misinterpretations in nanomaterial ecotoxicity measurements, Environ. Sci. Technol. 48 (2014) 4226 4246. [16] T.J. Anchordoquy, Y. Barenholz, D. Boraschi, et al., Mechanisms and barriers in cancer nanomedicine: addressing challenges, looking for solutions, ACS Nano 11 (2017) 12 18. [17] J.B. Coty, C. Vauthier, Characterization of nanomedicines: a reflection on a field under construction needed for clinical translation success, J. Control. Release 275 (2018) 254 268. [18] M.A. Dobrovolskaia, M. Shurin, A.A. Shvedova, Current understanding of interactions between nanoparticles and the immune system, Toxicol. Appl. Pharmacol. 299 (2016) 78 89. [19] I. Hamad, O. Al-Hanbali, A.C. Hunter, Distinct polymer architecture mediates switching of complement activation pathways at the nanosphere-serum interface: implications for stealth nanoparticle engineering, ACS Nano 4 (2010) 6629 6638. [20] S. Siegrist, E. Co¨rek, P. Detampel, et al., Preclinical hazard evaluation strategy for nanomedicines, Nanotoxicology 5 (2018) 1 27. [21] X.Q. Zhang, X. Xu, N. Bertrand, et al., Interactions of nanomaterials and biological systems: implications to personalized nanomedicine, Adv. Drug Deliv. Rev. 64 (2012) 1363 1384. [22] N. Kamaly, Z. Xiao, P.M. Valencia, Targeted polymeric therapeutic nanoparticles: design, development and clinical translation, Chem. Soc. Rev. 41 (2012) 2971 3010.

488

Handbook of Nanomaterials in Analytical Chemistry

[23] H.R. Lakkireddy, D. Bazile, Building the design, translation and development principles of polymeric nanomedicines using the case of clinically advanced poly(lactide (glycolide)) poly(ethylene glycol) nanotechnology as a model: an industrial viewpoint, Adv. Drug Deliv. Rev. 107 (2016) 289 332. [24] M.A. Dobrovolskaia, Pre-clinical immunotoxicity studies of nanotechnologyformulated drugs: challenges, considerations and strategy, J. Control. Release 220 (Pt B) (2015) 571 583. [25] H.R. Lakkireddy, M. Urmann, M. Besenius, Oral delivery of diabetes peptides— comparing standard formulations incorporating functional excipients and nanotechnologies in the translational context, Adv. Drug Deliv. Rev. 106 (Pt B) (2016) 196 222. [26] S. Bremer-Hoffmann, B. Halamoda-Kenzaoui, S.E. Borgos, Identification of regulatory needs for nanomedicines, J. Interdis. Nanomed. 3 (2018) 4 15. [27] S. Gioria, F. Caputo, P. Urba´n, Are existing standard methods suitable for the evaluation of nanomedicines: some case studies, Nanomedicine (Lond.) 13 (2018) 539 554. [28] J.B. Coty, E. Eleamen Oliviera, C. Vauthier, Tuning complement activation and pathway through controlled molecular architecture of dextran chains in nanoparticle corona, Int. J. Pharm. 532 (2017) 769 778. [29] C.N. Cruz, K.M. Tyner, L. Velazquez, CDER risk assessment exercise to evaluate potential risks from the use of nanomaterials in drug products, AAPS J. 15 (2013) 623 628. [30] ISO search engine web site, ,https://www.iso.org/home.html. (accessed 21.01.19). [31] E. Mansfield, D.L. Kaiser, D. Fujita, et al. (Eds.), Metrology and Standardization for Nanotechnology: Protocols and Industrial Innovations, Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, Germany, 2017. ISBN: 978-3-527-34039. 626 pages. [32] NIH-NCL web site, ,ncl.cancer.gov/. (accessed 16.01.19). [33] NIH-NCLweb site, NIH-NCL assay cascade, ,ncl.cancer.gov/resources/assay-cascadeprotocols. (accessed 16.01.19). [34] EU-NCL web site, ,www.euncl.eu/about-us/overview/. (accessed 16.01.19). [35] EU-NCL web site, EU-NCL assay cascade, ,www.euncl.eu/about-us/assay-cascade/. (accessed 16.01.19). [36] F. Varenne, J. Botton, C. Merlet, et al., Standardization and validation of a protocol of size measurements by dynamic light scattering for monodispersed stable nanomaterial characterization, Colloids Surf., A 486 (2015) 124 138. [37] F. Varenne, J. Botton, C. Merlet, et al., Standardization and validation of a protocol of zeta potential measurements by electrophoretic light scattering for nanomaterial characterization, Colloids Surf., A 486 (2015) 218 231. Erratum to [Colloids Surf., A 486 (2015) 218 231] Colloids Surf., A 498 (2016) 283 284. [38] F. Varenne, H. Hillaireau, J. Bataille, et al., Application of validated protocols to characterize size and zeta potential of dispersed materials using light scattering methods, Colloids Surf., A 560 (2019) 418 425, doi:10.1016/j.colsurfa.2018.09.006. [39] GUM, Guide to the expression of uncertainty in measurement, in: JCGM 100:2008 GUM1995 with minor corrections, 1995, ,www.bipm.org/utils/common/documents/ jcgm/JCGM_100_2008_E.pdf. (accessed 27.01.19). [40] F. Varenne, E. Rustique, J. Botton, et al., Towards quality assessed characterization of nanomaterial: transfer of validated protocols for size measurement by dynamic light scattering and evaluation of zeta potential by electrophoretic light scattering, Int. J. Pharm. 528 (2017) 299 311.

Issues related with the analysis of nanomaterials

489

[41] D. Langevin, O. Lozano, A. Salvati, Inter-laboratory comparison of nanoparticle size measurements using dynamic light scattering and differential centrifugal sedimentation, NanoImpact 10 (2018) 97 107. [42] D. Langevin, E. Raspaud, S. Mariot, Towards reproducible measurement of nanoparticle size using dynamic light scattering: important controls and considerations, NanoImpact 10 (2018) 161 167. [43] V. Filipe, A. Hawe, W. Jiskoot, Critical evaluation of nanoparticle tracking analysis (NTA) by NanoSight for the measurement of nanoparticles and protein aggregates, Pharm. Res. 27 (2010) 796 810. [44] FDA web site, Nanotechnology guidance documents updated 23 March 2018, 2018, ,www.fda.gov/ScienceResearch/SpecialTopics/Nanotechnology/ucm602536.htm. and Nanotechnology fact sheets updated 23 March 2018, ,www.fda.gov/ScienceResearch/ SpecialTopics/Nanotechnology/ucm402230.htm. (accessed 27.01.19). [45] H. Rauscher, K. Rasmussen, B. Sokull-Klu¨ugen, Regulatory aspects of nanomaterials in the EU, Chem. Ing. Tech. 89 (2017) 224 231. [46] REACH web site, REACH legislation from 18 December 2006, in: Regulation (EC) No 1907/2006, ,echa.europa.eu/regulations/reach/legislation. (accessed 16.01.19). [47] E. Lepeltier, C. Bourgaux, V. Rosilio, et al., Self-assembly of squalene-based nucleolipids: relating the chemical structure of the bioconjugates to the architecture of the nanoparticles, Langmuir 29 (2013) 14795 14803. [48] Z. Luo, D. Marson, Q.K. Ong, et al., Quantitative 3D determination of self-assembled structures on nanoparticles using small angle neutron scattering, Nat. Commun. 9 (2018) 1343. [49] C. Vauthier, P. Lindner, B. Cabane, Configuration of bovine serum albumin adsorbed on polymer particles with grafted dextran corona, Colloids Surf. B: Biointerfaces 69 (2009) 207 215. [50] S. Helvig, I.D.M. Azmi, S.M. Moghimi, Recent advances in cryo-TEM imaging of soft lipid nanoparticles, AIMS Biophys. 2 (2015) 116 130. [51] B. Angelov, A. Angelova, M. Drechsler, et al., Identification of large channels in cationic PEGylated cubosome nanoparticles by synchrotron radiation SAXS and cryoTEM imaging, Soft Matter 11 (2015) 3686 3692. [52] M.A. Moradi, P.H.H. Bomans, A.W. Jackso, et al., A quantitative cryoTEM study on crosslinked nanocapsule morphology in RAFT-based vesicle polymerization, Eur. Polym. J. 108 (2018) 329 336. [53] D. Cressey, E. Callaway, Cryo-electron microscopy wins chemistry Nobel: Jacques Dubochet, Joachim Frank and Richard Henderson share the prize for developing a technique to image biomolecules, Nature 550 (2017) 167. [54] Z. Hong Zhou, Atomic resolution cryo-electron microscopy of macromolecular complexes, Adv. Protein Chem. Struct. Biol. 82 (2011) 1 35. [55] P.S. Shen, The 2017 Nobel Prize in Chemistry: cryo-EM comes of age, Anal. Bioanal. Chem. 410 (2018) 2053 2057. [56] D.R. Baer, M.H. Engelhard, G.E. Johnson, Surface characterization of nanomaterials and nanoparticles: important needs and challenging opportunities, J. Vac. Sci. Technol. A 31 (2013) 50820. [57] J. Kovac, Surface characterization of polymers by XPS and SIMS techniques, Mater. Technol. 3 (2011) 191 197. [58] C.M. Chan, L.T. Weng, Surface characterization of polymer blends by XPS and ToFSIMS, Materials (Basel) 9 (8) (2016) E655.

490

Handbook of Nanomaterials in Analytical Chemistry

[59] D. Labarre, C. Vauthier, C. Chauvierre, Interactions of blood proteins with poly(isobutylcyanoacrylate) nanoparticles decorated with a polysaccharidic brush, Biomaterials 26 (2005) 5075 5084. [60] A. Layre, P. Couvreur, H. Chacun, et al., Novel composite core-shell nanoparticles as busulfan carriers, J. Control. Release 111 (2006) 271 280. [61] M.T. Peracchia, C. Vauthier, D. Desmae¨le, et al., Pegylated nanoparticles from a novel methoxypolyethylene glycol cyanoacrylate-hexadecyl cyanoacrylate amphiphilic copolymer, Pharm. Res. 15 (1998) 550 556. [62] J.S. Suk, Q. Xu, N. Kim, et al., PEGylation as a strategy for improving nanoparticlebased drug and gene delivery, Adv. Drug Deliv. Rev. 99 (2016) 28 51. [63] I. Nasir, W. Fatih, A. Svensson, et al., High throughput screening method to explore protein interactions with nanoparticles, PLoS One 10 (2015) e0136687. [64] J.B. Coty, F. Varenne, A. Benmalek, Characterization of nanomedicines’ surface coverage using molecular probes and capillary electrophoresis, Eur. J. Pharm. Biopharm. 130 (2018) 48 58.

Further reading S.S. Chaurasia, R.R. Lim, R. Lakshminarayanan, Nanomedicine approaches for corneal diseases, J. Funct. Biomater. 6 (2015) 277 298. ICH, ICH Harmonized Tripartite Guideline, Validation of Analytical Procedures: Text and Methodology Q2(R1), Current Step 4 Version, Parent Guideline Dated 27 October 1994, (Complementary Guideline on Methodology Dated 6 November 1996 Incorporated in November 2005), ,www.ich.org/products/guidelines/quality/article/quality-guidelines. html. (accessed 27.01.19).

Graphene quantum dots in biomedical applications: recent advances and future challenges

20

Xianxian Zhao1,2, Weiyin Gao3, Hong Zhang1, Xiaopei Qiu3 and Yang Luo1,4 1 Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, P.R. China, 2Department of Laboratory Medical Science, Southwest Hospital, Third Military Medical University, Chongqing, P.R. China, 3Department of Urology, The Second Affiliated Hospital of Nanchang University, Nanchang, P.R. China, 4Center of Laboratory Medicine, Medical School of Chongqing University, Chongqing, P.R. China

Graphene quantum dots (GQDs), known as a novel type of zero-dimensional luminescent nanomaterials, are small graphene fragments to cause excitation confinement in 3 20 nm particles and quantum-size effect [1]. GQDs exhibit extraordinary optoelectronic properties as well as excellent biocompatibility and low-cost preparation methods, by which they hold potentials in replacing those well-known metal chalcogenides based quantum dots [2]. Besides, the p p bonds below and above the atomic plane give graphene exceptional thermal and electrical conductivity, compared with conventional semiconductor quantum dots, making GQDs possess their favorable attributes without incurring the burden of intrinsic toxicity (Fig. 20.1A) [3 7]. The quantum-confinement effect and the variation in density and nature of sp2 sites available in GQDs make their optical properties greatly depend on their size so that the energy band gap of GQDs can be tuned by modulating their size [8]. Over the past few decades, quantum dots with steadily increasing research have been occupied a special status in nanomaterial fields and have made considerable progress, but in recent years, graphene-based nanohybrid has captured more interest and imagination in scientific research [9]. Owing to its extraordinary mechanical properties, such as biocompatibility, transparency, and electrical conductivity, GQDs have obtained a rapid growth as breakthrough tools for various purposes in many fields of science, including photonics, composites, energy, and electronics. Meanwhile, GQD-based nanomaterials have already shown a promising future in biomedical fields, particularly for diagnostics [10 14], drug delivery [15], nearinfrared (NIR) light-induced photothermal therapy [16 18], in vitro and in vivo bioimaging [19 21]. In addition to those fundamental applications as mentioned above, Ding et al. have reported a GQD-based anticancer drug carrier and a signaler for indicating drug delivery, release, and response by providing distinct Handbook of Nanomaterials in Analytical Chemistry. DOI: https://doi.org/10.1016/B978-0-12-816699-4.00020-7 Copyright © 2020 Elsevier Inc. All rights reserved.

494

Handbook of Nanomaterials in Analytical Chemistry

Figure 20.1 Preparation and properties of GQDs: (A) synthesis process under ultraviolet irradiation. The prepared GQDs aqueous solution was obtained. (B) Preparation of GQDs with microwave-assisted hydrothermal method. (C) Schematic representation of GQDs prepared by solvothermal method. (D) Synthesis process of the photoluminescent GQDs by using hexa-peri-hexabenzocoronene as materials. GQD, graphene quantum dot.

fluorescence signals at different stages [22]. This research of multifunctional GQDs provides a new direction in future biomedical applications. In this chapter the applications of GQDs in biomedical fields, including biomolecule detection, bioimaging, drug delivery, and cancer therapy, will be reviewed. Future perspectives and challenges for applying GQD-based materials in nanomedicine fields will also be covered.

20.1

Synthetic considerations

20.1.1 Preparation and physicochemical properties of graphene quantum dots In order to be explored in biomedical applications, GQDs are commonly synthesized by a multistep synthetic and preparatory process, ensuring their solubility and biocompatibility. Those synthesis methods can be briefly classified into two categories: top-down methods and bottom-up routes. The top-down methods that dominated in nanoscience by cutting down large graphene-sheet carbon nanotubes (Fig. 20.1B) [23,24], carbon fibers or graphite into small pieces of graphene sheets are the most suitable for mass production; on the contrary, the bottom-up routes that require small molecules to be starting materials for GQDs buildup are particularly appropriate for controlling the size of GQDs but require multistep organic reactions and purification at each step. Therefore, those top-down approaches exemplified as nanolithography technique, acidic oxidation, hydrothermal or

Graphene quantum dots in biomedical applications: recent advances and future challenges

495

solvothermal microwave-assisted [25], sonication-assisted, and chemical exfoliation methods have been widely used to synthesize GQDs. While for the bottom-up techniques, ultraviolet irradiation method using oxygen-containing aromatic compounds as starting materials [26], microwave-assisted hydrothermal method using carbonization as starting materials [27], ruthenium-catalyzed cage-opening method using fullerenes as starting materials, one-step solvothermal method using hydrogen peroxide and expanded graphite as starting materials, and the method using unsubstituted hexa-peri-hexabenzocoronene as the carbon source through the process of surface functionalization (Fig. 20.1C), oxidization, carbonization, and reduction have successively been utilized to prepare GQDs recently (Fig. 20.1D) [29]. Based on these two classic synthetic methods, GQDs with physicochemical properties can be prepared for different applications. The next section will focus on the properties of GQDs briefly. Owing to these specific routes for synthesis, GQDs with excellent electrical conductivity, optical transparency, and mechanical stability have mostly been utilized for electronic, electrochemical, and optical applications. It has the property of extremely high intrinsic mobility of charge carriers [30]. Among various nanographene materials, GQDs have attracted increasing research interest because of its nonzero band gap induced by quantum-confinement and edge effects [31]. Meanwhile, the high solubility of the GQDs in common solvents is also very important for experimental studies, surface modified GQDs may contain carboxylic acid groups at their edges that make them highly soluble in water and suitable for further modification with other functional molecules such as organic/inorganic and biological components [32]. Liu et al. proposed a three-step mechanism to elucidate the complex aggregation of GQDs in aqueous solution, which enables us to simplify the interpretation of experimental results for applying readily available, versatile ensemble characterization techniques, together with the structural uniformity [33].

20.2

Biomedical applications of graphene quantum dots

20.2.1 Graphene quantum dots for in vitro biomarkers detection 20.2.1.1 Graphene quantum dot based immunological assay Immunosensors are fast and simple analytical methods for the determination of many clinical diseases and biochemical compositions that relies on classical antibody antigen (Ab Ag) interactions, which supply a hopeful strategy for clinical diagnostics, due to their specific and sensitive properties. Conventionally, immunosensors are based on recognizing the complexity of an antigen with a specific antibody coupling, one of which could be immobilized on the solid substrate for observation; afterward a signal change will occur upon formation of an Ab Ag complex. Highly sensitive immunosensors can thus be constructed by applying enzymatic reactions involving fixing enzyme-labeled antigen [34]. The beneficial structural and compositional synergy of graphene allows GQDs to be excellent materials for fabricating various immunosensing platforms. Immunosensors can be

496

Handbook of Nanomaterials in Analytical Chemistry

classified into electrochemical [35], amperometric, piezoelectric [36], thermometric or magnetic [37], according to the type of transduction. Electrochemical immunosensors. Electrochemical immunosensors have gained much research concern because of the integration of advantages of label-free and Ab Ag interaction at the surface of the detection device, by which any change in potential that reflects the existence of specific protein or peptide could be finally measured. A functionalized and ultrasensitive electrochemical immunosensor based on the nitrogen-doped GQDs (N-GQDs) supported PtPd bimetallic nanoparticles was developed by Yang et al. for the detection of carcinoembryonic antigen (CEA), demonstrating a wide dynamic range ranging from 5 fg mL21 to 50 ng mL21 with a low detection limit of 2 fg mL21 (S/N 5 3) for the detection of CEA (Fig. 20.2A) [3]. Meanwhile, GQD-based immunosensors for detection of a cardiac biomarker in human heart attack have aroused researchers’ interest recently. In a GQD fluorescence resonance emergency transference (FRET) based biosensor for the detection of cardiac Troponin I (cTnI), results demonstrated higher specificity, the lower limit of detection (0.192 pg mL21), and less time (10 min) comparing to traditional detection method (Fig. 20.2B) [38]. Similar results have been obtained in another study of cTnI detection using GQD-PAMAM nanohybrid modified gold (Au) screen-printed electrode (Fig. 20.2C) [39]. Electrochemical immunosensors based

Figure 20.2 Three kinds of electrochemical immunosensors based on GQDs. (A) The label-free electrochemical immunosensor and the preparation procedure of PtPd/ N-GQDs@Au. (B) The reaction between cardiac antibody and functionalized GQDs with sensing mechanism of FRET: (a) bioconjugation of the monoclonal antibody anti-cTnI with afGQDs using EDC NHS chemistry. (b) Schematic mechanism of immunosensing based on specific interaction of anti-cTnI/afGQDs with graphene. cTnI, Cardiac Troponin I; 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide (EDC-NHS); FRET, fluorescence resonance emergency transference; GQD, graphene quantum dot; PtPd/N-GQD, PtPd bimetallic nanoparticle.

Graphene quantum dots in biomedical applications: recent advances and future challenges

497

on GQDs are the most heated research orientation in recent years, and the enthusiasm for research on it will not be easily extinguished. Amperometric immunosensors. Comparing with other kinds of immunosensors as previously mentioned, amperometric immunosensors are far more broadly investigated due to their easy fabrication, miniaturization, robustness, and cost effectiveness [40]. Huang et al. developed a simple amperometric immunosensor based on TiO2 graphene, chitosan, and gold nanoparticles (AuNPs) composite film modified glassy carbon electrode (GCE) for protein detection. The negatively charged AuNPs can be adsorbed on the positively charged chitosan/TiO2 graphene composite film by electrostatic adsorption and then used to immobilize a-fetoprotein (AFP) antibody for the assay of AFP. By using this strategy, a wide detection range (0.1 300 ng mL21) with the correlation coefficients of 0.992 0.994 for model target AFP is obtained. The limit of detection is 1.3 ng mL21 at a S/N ratio of 3 [41]. The research on amperometric immunosensors has resemblance with that on electrochemical immunosensors. Other types of immunosensors. Coupling immunoassay techniques with surface plasmon resonance technology are the principles of optical immunosensors. A change in refractive index of the medium upon interaction of Ag (tumor marker) with specific antibodies immobilized on the sensor surface can be measured [42]. Alternatively, antibodies could be immobilized on the surface of an optical fiber so that any change in refractive index, fluorescence or luminescence correlated with several antigens interacting with the antibodies could be measured. The principle of piezoelectric immunosensors is commonly utilized by evaluating the change in frequency of oscillation as result of a change in mass on the interaction of antigens with antibodies immobilized on quartz crystal [43]. These kinds of immunosensors are not well applied in biomedical fields mainly due to their high cost, difficulty in mass production, and problems with mechanical and electromagnetic interference.

20.2.1.2 Graphene quantum dot based nucleic acid assay As they provide a simple, accurate, and cheap platform for DNA detection, electrochemical detection methods based on GQDs biosensors are extensively adopted in the various nucleic acid assays. In addition, electrochemical DNA sensors can improve the immobilization of single-stranded DNA probe sequences on a mass variety of electrode substrates [44,45]. Qian et al. introduced a method to achieve the analysis of the low concentration of DNA by taking advantage of excellent biocompatibility and powerful fluorescence of GQDs, one base pair DNA mismatch specificity and unique FRET between carbon nanotubes and GQDs [46]. Hu et al. constructed a double-stranded DNA structure by the hybridization of thiol-tethered oligodeoxynucleotide probes (capture DNA) that was assembled on the gold electrode surface with target DNA and aminated indicator probe (NH2-DNA). After the construction of the double-stranded DNA structure, activated carboxyl groups of GQDs assembled on NH2-DNA could be applied for DNA recognition. GQDs were used as a new platform for horseradish peroxidase immobilization through the noncovalent assembly. With the integration of GQDs and enzyme

498

Handbook of Nanomaterials in Analytical Chemistry

catalysis the proposed biosensor could detect miRNA-155 from 1 fM to 100 pM with a detection limit of 0.14 fM [47]. At present, development of DNA/RNA sensors is receiving considerable attention in biomedical field with the scope of improving the sensitivity and selectivity of sensors.

20.2.2 Graphene quantum dots for in vivo imaging On account of relatively high quantum yields with high molar extinction coefficients, broad absorption with narrow emission spectra, and high photostability, the strong quantum-confinement and edge effects stir GQDs wide applications in biological imaging [48,49]. Thus choosing suitable probes plays a significant role in bioimaging purposes since the resolution, sensitivity, and versatility of fluorescence microscopy are mainly dependent on the properties of various fluorescent probes. The novel GQDs derived nanomaterials featured by many advantages comparing with a traditional imaging modality, such as only a small number of GQDs are needed to generate the signal due to the highly stable and bright fluorescence. Meanwhile, GQDs with the NIR reflectance emission property are promising candidates for the imaging of deeper tissue samples. Based on the above reasons, applying GQDs as contrast agents for in vivo imaging has been the area of high expectations and recurring attention. The NIR emitting window shows great advantages for biomedical imaging because of the low tissue absorption and reduced light scattering in more than 650 nm wavelengths’ region. NIR GQDs based nanoprobe for ascorbic acid (AA) detection in living cells was reported by Tan et al. They announced that GQD possessed good two-photon (TP) fluorescence properties showing an emitted NIR reflectance (660 nm) upon excited with 810 nm femtosecond pulses and a TP excitation action cross-section of 25.12 GM. They were then employed to construct a TP nanoprobe for the detection and bioimaging of endogenous AA in living cells. In this nanosystem, NIR reflectance GQDs, which exhibited lower fluorescence background in the living system to afford improved fluorescence imaging resolution, were acted as fluorescence reporters [50]. Doping GQDs with heteroatoms has recently been the trend because of the quickly expanded research needs in cell imaging, it can be an effective way to modulate the band gap, tune electronic density, and chemical activity of GQDs, which endows the heteroatoms-doped GQDs new optical phenomena and unexpected properties for practical applications. A N-GQD was composed for photodynamic antimicrobial therapy and bioimaging, the result showed the intrinsic luminescence properties of the N-GQD in NIR region and high photostability enable it to be exploited as a promising contrast agent to track bacteria in bioimaging [51].

20.2.3 Graphene quantum dot based platforms for drug delivery To improve the water solubility and the specific targeting of drugs, various nanocarriers have been developed. Multifunctional GQDs usually serve as drug carriers and targeted cellular imaging simultaneously, which can be used in cancer therapy.

Graphene quantum dots in biomedical applications: recent advances and future challenges

499

Drug delivery systems could be visualized by using organic fluorophores and semiconductor quantum dots to understand the cellular uptake, while we can easily monitor movement in the cells in real time without employing external dyes considering the inherent fluorescence of GQDs [52]. An experiment showed that synthesized folic acid (FA) conjugated GQDs could be utilized to load the antitumor drug doxorubicin (DOX). The fabricated nano-assembly can be unambiguously discriminate cancer cells from normal cells and efficiently deliver the drug to target cells. The inherent stable fluorescence of GQDs enables real-time monitoring of cellular uptake of the DOX GQD FA nano-assembly and the consequent release of drugs. The nano-assembly is specifically internalized rapidly by HeLa cells via receptor-mediated endocytosis, whereas DOX release and accumulation are prolonged. In vitro toxicity, data suggest that the DOX GQD FA nano-assembly can target HeLa cells differentially and efficiently while exhibiting significantly reduced cytotoxicity on nontarget cells (Fig. 20.3A and B) [53]. A new hybrid nanosystem powerful multimodal tool for the treatment and imaging of cancer has been reported in which GQDs were used as a multifunctional nanocarrier to load gadolinium texaphyrin and lutetium texaphyrin for biological redox therapy enhanced photodynamic and photothermal therapy, which exhibits tumor-responsive deep-red fluorescence and enhanced T1-weighted MRI that enable imaging of the tumor during treatment. GQD sheets can increase their drug loading capacity via their unique structure of two faces and edges. Based on this, Khodadadei et al. synthesized 10 nm size N-GQDs with 10 graphitic layers loading methotrexate to construct a drug delivery system and the results revealed that GQDs as nanocarriers had stronger antitumor cells activities since it can prolong the

Figure 20.3 GQDs-based nanocomposites in drug delivery. (A) TEM image of GQDs. (B) FTIR spectra of GQDs and GQD FA. (C) TEM image of N-GQDs. (D) FTIR spectra of (a) N-GQDs and (b) MTX (N-GQDs). FA, folic acid; GQD, graphene quantum dot; MTX, methotrexate; N-GQD, nitrogen-doped GQD.

500

Handbook of Nanomaterials in Analytical Chemistry

cytotoxic effects of loaded drug (Fig. 20.3C and D) [18]. The receptor-mediated endocytosis of GQDs promised a more accurate and selective cancer diagnostic approach.

20.3

Toxicity research of graphene quantum dot materials

The toxicity of nanomaterials is one of the major challenges facing their applications in biotechnology. Studies on the cytotoxicity of graphene-based materials have stated briefly that GQDs with a less than 50-nm side edge caused no obvious toxicity to a series of cells (Fig. 20.4A) [54]. Since single-dosing experiment had no obvious accumulation and mostly presented low toxicity of nanomaterials, multiple-dosing which simulated clinical drug administration was applied to the study of in vivo toxicity to further investigate the biosafety of GQDs [55]. Nurunnabi et al. performed in vitro cytotoxicity studies on carboxylated GQDs and observed no toxicity (Fig. 20.4B) [56]. Peng et al. have found that nanosized graphene oxides did not lead to serious acute cytotoxicity to HeLa cells at a concentration of 40 lg mL21 [57]. Li et al. observed no distinct cell death by incubating graphene oxide nanoparticles with gastric cancer cells and skin cells at a dose up to 100 lg mL21 (Fig. 20.4C) [58]. With the cytotoxicity studies of GQDs, it is important to assess

Figure 20.4 Researches on toxicity of GQDs. (A) Results all suggest no obvious toxicity of GQD-PEG to HeLa cells at GQD concentration as high as 160 mg mL21. (B) Cellular cytotoxicity of Fluo G, PEG G, and GO to HeLa cells (incubated with different concentrations of graphene derivatives for an additional 24 h in fresh medium). (C) (a) Cell viability of NIH-3 T3 cells studied by MTT method and the cells were treated in cell culture media with GQDs (0, 5, and 50 lg mL21) for 3 and 24 h, respectively. (b) Average numbers of NIH-3 T3 cells after the addition of GQDs for 0, 24, and 48 h post incubation. GQD, Graphene quantum dot.

Graphene quantum dots in biomedical applications: recent advances and future challenges

501

the potential compromises of GQDs to DNA damage since there is a close correlation between DNA damage and variation or cancer. In a research reported by Wang et al., genotoxicity of GQDs to NIH-3 T3 cells was inquired by the analysis of flow cytometry for DNA damage related protein activation, while the GQD-induced ROS generation was studied as a potential cause for DNA damage. The cellular uptake of GQDs, as well as cell death and proliferation of NIH-3 T3 cells treated with GQDs, was also studied to assess the cytotoxicity of GQDs [59]. Yuan et al. investigated the cell distribution of three GQDs modified with different functional groups [NH2, COOH, and CO N(CH3)2, respectively] and compared their cytotoxicity in A549 and C6 cells, no visible mortality and apoptosis or necrosis increases resulted from the treatment of the three GQDs even at the concentration of 200 lg mL21, the results manifested that when modified with different chemical groups, GQDs still possessed excellent biocompatibility and low cytotoxicity to cells, which may make them more promising in bioimaging and other biomedical applications. Markovic et al. analyzed GQD-mediated photodynamic cytotoxicity in terms of molecular mechanisms, showing that the induction of oxidative stress generated in vitro photodynamic cytotoxicity of GQD and subsequent activation of both apoptosis and autophagy programed cell death. But human breast cancer studies have indicated that they are nontoxic materials since GQDs can rapidly get into the cytoplasm and do not interfere with cell proliferation. These results from the cytotoxicity studies at the cellular level are in favor of GQDs for biomedical applications. But as a precaution, more attention should be paid to the safety of GQDs by studying their intracellular and in vivo metabolic pathways of toxicity, cellular uptake mechanisms.

20.4

Conclusion and perspectives

One of the key difficulties facing researchers aiming to develop GQDs for nanomedical applications is to obtain high-quality products; the existing synthesis method generally allows small-scale production of GQDs which have a wide size distribution. It is necessary to find easy purification methods and seek out novel methods to achieve a high yield that does not require the removal of starting materials. Since the size and shape have a massive impact on the physicochemical properties of GQDs, mass theoretical and practical research must focus on improving synthetic method if the GQDs-based fluorescence detection methods gradually replace the traditional detection technique used in laboratory inspection. More studies concerning the application of GQDs-based immunosensing are needed in comparison with the nonimmunosensing. Because of the small number of researches on immunosensors based on GQDs, more techniques should be involved in this area and novel protocols for detection of cell lines, cancer biomarkers, and disease should be developed, since that the synthetic of the new technologies will bring significant input to ultrasensitive immunosensors relevant to diagnostics, and therapy of cancer. Understanding the photoluminescence (PL) properties of GQDs is still poor, although some possible mechanisms have been proposed, such as size effect,

502

Handbook of Nanomaterials in Analytical Chemistry

surface modification, and doping with other elements. Despite the achievement of GQDs with different colored PL properties, including PL in the NIR region, the quantum yields of most GQDs are still at a low level, so the improvement of GQDs is imperative because of their restricted application in immunosensing from their lower quantum yields. Metal-enhanced fluorescence may be considered for quantum yield escalation and a study has proved its possibility. Although advances are exciting and encouraging, the use of GQDs for immunosensing applications is still in infancy, with a lot of challenges remaining. A new strategy for surface modification is needed to be developed for application in immunosensing. With their uniform size, excellent PL, and high quantum yields, GQDs will no doubt be used in more creative applications. In summary, GQDs emerge as a novel nanomaterial platform for immunosensing, effective collaboration between multiple disciplines including chemistry, physics, biology, and medicine must be implemented. In this chapter, we have summarized recent research progress of GQDs-based nanomaterials, focusing on their synthesis, typical properties, and biomedical applications including in vitro and in vivo, we also share a brief introduction about the in vivo toxicity of GQDs mainly based on cell level. Finally, we conclude that there is a promising future for further advances and developments of GQDs-based nanomaterials.

References [1] S. Benı´tez-Martı´nez, M. Valca´rcel, Graphene quantum dots in analytical science, TrAC Trends Anal. Chem. 72 (2015) 93 113. [2] M. Arvand, S. Hammett, Analytical methodology for the electro-catalytic determination of estradiol and progesterone based on graphene quantum dots and poly(sulfosalicylic acid) co-modified electrode, Talanta 174 (2017) 243 255. [3] J. Zhu, et al., Green, rapid, and universal preparation approach of graphene quantum dots under ultraviolet irradiation, ACS Appl. Mater. Interfaces 9 (2017) 14470 14477. [4] N. Zhang, et al., Quantum-dots-based photoelectrochemical bioanalysis highlighted with recent examples, Biosens. Bioelectron. 94 (2017) 207 218. [5] X. Zhou, et al., A sensing approach for dopamine determination by boronic acidfunctionalized molecularly imprinted graphene quantum dots composite, Appl. Surf. Sci. 423 (2017) 810 816. [6] C.S. Lim, et al., Graphene and carbon quantum dots electrochemistry, Electrochem. Commun. 52 (2015) 75 79. [7] H. Zhao, et al., Graphene-based nanomaterials for drug and/or gene delivery, bioimaging, and tissue engineering, Drug Discov. Today 22 (2017) 1302 1317. [8] P. Gong, et al., Small but strong: the influence of fluorine atoms on formation and performance of graphene quantum dots using a gradient F-sacrifice strategy, Carbon 112 (2017) 63 71. [9] X. Zou, et al., Mechanisms of the antimicrobial activities of graphene materials, J. Am. Chem. Soc. 138 (2016) 2064 2077. [10] N. Cai, et al., Biosensing platform for the detection of uric acid based on graphene quantum dots and G-quadruplex/hemin DNAzyme, Anal. Chim. Acta 965 (2017) 96 102.

Graphene quantum dots in biomedical applications: recent advances and future challenges

503

[11] J. Guo, et al., Development of a novel quantum dots and graphene oxide based FRET assay for rapid detection of in vA gene of salmonella, Front. Microbiol. 8 (2017) 8. [12] H. Huang, et al., Fluorescence turn-on sensing of ascorbic acid and alkaline phosphatase activity based on graphene quantum dots, Sens. Actuators, B 235 (2016) 356 361. [13] Z.S. Qian, et al., A fluorescent nanosensor based on graphene quantum dots - aptamer probe and graphene oxide platform for detection of lead(II) ion, Biosens. Bioelectron. 68 (2015) 225 231. [14] J. Zhao, et al., Graphene quantum dots as effective probes for label-free fluorescence detection of dopamine, Sens. Actuators, B 223 (2016) 246 251. [15] D. Iannazzo, et al., Graphene quantum dots for cancer targeted drug delivery, Int. J. Pharm. 518 (2017) 185 192. [16] J. Fan, D. Li, X. Wang, Effect of modified graphene quantum dots on photocatalytic degradation property, Diamond Relat. Mater. 69 (2016) 81 85. [17] Y. Yang, et al., Increasing cancer therapy efficiency through targeting and localized light activation, ACS Appl. Mater. Interfaces 9 (2017) 23400 23408. [18] F. Cheng, et al., Graphene quantum dots in biomedical applications: recent advances and future challenges, Front. Lab. Med. 1 (4) (2017) 192 199. [19] W.S. Kuo, et al., Graphene quantum dots with nitrogen-doped content dependence for highly efficient dual-modality photodynamic antimicrobial therapy and bioimaging, Biomaterials 120 (2017) 185 194. [20] J. Lin, X. Chen, P. Huang, Graphene-based nanomaterials for bioimaging, Adv. Drug Delivery Rev. 105 (2016) 242 254. [21] G. Reina, et al., Promises, facts and challenges for graphene in biomedical applications, Chem. Soc. Rev. 46 (2017) 4400 4416. [22] H. Ding, et al., Beyond a carrier: graphene quantum dots as a probe for programmatically monitoring anti-cancer drug delivery, release, and response, ACS Appl. Mater. Interfaces 9 (2017) 27396 27401. [23] S.H. Kang, et al., Ultrafast method for selective design of graphene quantum dots with highly efficient blue emission, Sci. Rep. 6 (2016) 38423. [24] Y. Dong, et al., Etching single-wall carbon nanotubes into green and yellow singlelayer graphene quantum dots, Carbon 64 (2013) 245 251. [25] L. Tang, et al., Deep ultraviolet photoluminescence of water-soluble self-passivated graphene quantum dots, ACS Nano 6 (2012) 5102 5110. [26] N.L. Teradal, R. Jelinek, Carbon nanomaterials in biological studies and biomedicine, Adv. Healthcare Mater. 6 (2017). [27] S. Bak, D. Kim, H. Lee, Graphene quantum dots and their possible energy applications: a review, Curr. Appl. Phys. 16 (2016) 1192 1201. [28] R. Tian, et al., Solvothermal method to prepare graphene quantum dots by hydrogen peroxide, Opt. Mater. 60 (2016) 204 208. [29] R. Liu, et al., Bottom-up fabrication of photoluminescent graphene quantum dots with uniform morphology, J. Am. Chem. Soc. 133 (2011) 15221 15223. [30] P. Miao, et al., Recent advances in carbon nanodots: synthesis, properties and biomedical applications, Nanoscale 7 (2015) 1586 1595. [31] S. Li, et al., Exceptionally high payload of the IR780 iodide on folic acidfunctionalized graphene quantum dots for targeted photothermal therapy, ACS Appl. Mater. Interfaces 9 (2017) 22332 22341. [32] T.H. Kim, D. Lee, J.W. Choi, Live cell biosensing platforms using graphene-based hybrid nanomaterials, Biosens. Bioelectron. 94 (2017) 485 499.

504

Handbook of Nanomaterials in Analytical Chemistry

[33] X. Liu, et al., Fluorescence turn-off-on probe based on polypyrrole/graphene quantum composites for selective and sensitive detection of paracetamol and ascorbic acid, Biosens. Bioelectron. 98 (2017) 222 226. [34] A. Klos-Witkowska, The phenomenon of fluorescence in immunosensors, Acta Biochim. Pol. 63 (2016) 215 221. [35] A.T. Lawal, Synthesis and utilisation of graphene for fabrication of electrochemical sensors, Talanta 131 (2015) 424 443. [36] M. Hasanzadeh, et al., Graphene quantum dots decorated with magnetic nanoparticles: synthesis, electrodeposition, characterization and application as an electrochemical sensor towards determination of some amino acids at physiological pH, Mater. Sci. Eng., C: Mater. Biol. Appl. 68 (2016) 814 830. [37] X. Wang, et al., Electrochemical immunosensor with graphene quantum dots and apoferritin-encapsulated Cu nanoparticles double-assisted signal amplification for detection of avian leukosis virus subgroup, J. Biosens. Bioelectron. 47 (2013) 171 177. [38] D. Bhatnagar, et al., Graphene quantum dots FRET based sensor for early detection of heart attack in human, Biosens. Bioelectron. 79 (2016) 495 499. [39] D. Bhatnagar, I. Kaur, A. Kumar, Ultrasensitive cardiac troponin I antibody based nanohybrid sensor for rapid detection of human heart attack, Int. J. Biol. Macromol. 95 (2017) 505 510. [40] H. Malekzad, et al., Highly sensitive immunosensing of prostate specific antigen using poly cysteine caped by graphene quantum dots and gold nanoparticle: a novel signal amplification strategy, Int. J. Biol. Macromol. 105 (2017) 522 532. [41] K.J. Huang, et al., Amperometric immunobiosensor for alpha-fetoprotein using Au nanoparticles/chitosan/TiO(2)-graphene composite based platform, Bioelectrochemistry 90 (2013) 18 23. [42] J. Keegan, et al., Detection of benzimidazole carbamates and amino metabolites in liver by surface plasmon resonance-biosensor, Anal. Chim. Acta 700 (2011) 41 48. [43] M.H. Mat Zaid, et al., PNA biosensor based on reduced graphene oxide/water soluble quantum dots for the detection of Mycobacterium tuberculosis, Sens. Actuators, B 241 (2017) 1024 1034. [44] P.A. Rasheed, N. Sandhyarani, Carbon nanostructures as immobilization platform for DNA: A review on current progress in electrochemical DNA sensors, Biosens. Bioelectron. 97 (2017) 226 237. [45] F. Khakbaz, M. Mahani, Micro-RNA detection based on fluorescence resonance energy transfer of DNA-carbon quantum dots probes, Anal. Biochem. 523 (2017) 32 38. [46] Z.S. Qian, et al., DNA nanosensor based on biocompatible graphene quantum dots and carbon nanotubes, Biosens. Bioelectron. 60 (2014) 64 70. [47] T. Hu, et al., Enzyme catalytic amplification of miRNA-155 detection with graphene quantum dot-based electrochemical biosensor, Biosens. Bioelectron. 77 (2016) 451 456. [48] E. Roy, et al., Introduction of selectivity and specificity to graphene using an inimitable combination of molecular imprinting and nanotechnology, Biosens. Bioelectron. 89 (2017) 234 248. [49] X. Yao, et al., Mesoporous silica nanoparticles capped with graphene quantum dots for potential chemo-photothermal synergistic cancer therapy, Langmuir 33 (2017) 591 599. [50] S. Wang, et al., Quantum dots in graphene nanoribbons, Nano Lett. 17 (2017) 4277 4283.

Graphene quantum dots in biomedical applications: recent advances and future challenges

505

[51] M.L. Chen, et al., Quantum-dot-conjugated graphene as a probe for simultaneous cancer-targeted fluorescent imaging, tracking, and monitoring drug delivery, Bioconjug. Chem. 24 (2013) 387 397. [52] Y. Lei, et al., Strongly coupled CdS/graphene quantum dots nanohybrids for highly efficient photocatalytic hydrogen evolution: unraveling the essential roles of graphene quantum dots, Appl. Catal., B 216 (2017) 59 69. [53] X. Wang, et al., Multifunctional graphene quantum dots for simultaneous targeted cellular imaging and drug delivery, Colloids Surf., B. 122 (2014) 638 644. [54] J. Wang, et al., Synthesis, characterization and cells and tissues imaging of carbon quantum dots, Opt. Mater. 72 (2017) 15 19. [55] Y. Chong, et al., The in vitro and in vivo toxicity of graphene quantum dots, Biomaterials 35 (2014) 5041 5048. [56] M. Nurunnabi, et al., In vivo biodistribution and toxicology of carboxylated graphene quantum dots, ACS Nano 7 (2013) 6858 6867. [57] C. Peng, et al., Intracellular imaging with a graphene-based fluorescent probe, Small 6 (2010) 1686 1692. [58] J.L. Li, et al., Graphene oxide nanoparticles as a nonbleaching optical probe for twophoton luminescence imaging and cell therapy, Angew. Chem. Int. Ed. 51 (2012) 1830 1834. [59] D. Wang, et al., Can graphene quantum dots cause DNA damage in cells? Nanoscale 7 (2015) 9894 9901.

Index

Note: Page numbers followed by “f” and “t” refer to figures and tables, respectively. A AA. See Ascorbic acid (AA) Ab-QD. See Antibody/QD (Ab-QD) Ab Ag interactions. See Antibody antigen interactions (Ab Ag interactions) Absolute sensitivity, 232 233 Accuracy, 31 Acephate, 424 Acetaminophen (APAP), 311 312, 363 365 Acetamiprid, 422 424 Acetone, 367 368 Acetylcholinesterase (AChE), 17 18, 348, 417 420 Acetylthiocholine (ATCh), 417 420 Acryloyl-β-cyclodextrin (Acryloyl-β-CD), 387 388 Active nanostructures, 33 Adsorption mechanism, electrodes modification based on, 284 285 Advanced functionalized nanomaterial-based electrochemical sensor methods, 298 Aerogels, 45 Aerosol optical depth (AOD), 450 451 of CAs, 454f Aflatoxins, 275 Aflatoxin B1 (AFB1), 275, 389 Aflatoxins M1 (ATM1), 282 284, 287 288 AFM. See Atomic force microscopy (AFM) α-fetoprotein, 332 Aluminum, 106 107 Aluminum oxide, 203 Amine-POSS, 105 3-Aminopropyl triethoxysilane, 165 (3-Aminopropyl)-trimethoxysilane (APTES), 209 211, 383 3-Aminopropyltriethoxysilane, 82

5-Aminosalicylic acid, 385 Aminosilanized GO, 384 Ammonia, 367 368 Amperometric aptasensor, 317 318 biosensor, 365 367 immunosensors, 497 i t curve technique, 301 sensor, 299 301 “Analyst”, 30 31 Analytical chemistry, 29, 35 36, 57, 377 basic principles, 30 31 history, 30 31 Anodization approaches, 203 Anti-Staphylococcal enterotoxin B antibody, 194 195 Antibody-functionalized magnetic nanowires, 136 137 Antibody/QD (Ab-QD), 334 335 Antibody antigen interactions (Ab Ag interactions), 495 496 AOD. See Aerosol optical depth (AOD) APAP. See Acetaminophen (APAP) Apo-NAA-DBRs. See NAA-apodized DBRs (Apo-NAA-DBRs) Apo-NAA-GIFs. See NAA-apodized GIFs (Apo-NAA-GIFs) Apparent quenching, 21 Aptamers, 317 318, 427 429 aptamer-based electrochemical sensor, 287 288 APTES. See (3-Aminopropyl)trimethoxysilane (APTES) Artificial peroxidase. See Prussian Blue Ascorbic acid (AA), 299 301, 349 350, 363 365, 422 424 Aspergillus flavus, 275 Aspergillus parasiticus, 275

508

ATCh. See Acetylthiocholine (ATCh) ATM1. See Aflatoxins M1 (ATM1) Atmospheric aerosol, 449 size fractions, 449 450 Atomic force microscopy (AFM), 166 167, 459 460, 474 475 Attenuated total reflection FTIR (ATR FTIR), 462 463 Au and Pd NP-modified nanoporous stainless steel (Au-Pd/NPSS), 304 Au NP/rGO nanocomposite (Au-NPs/rGO), 311 312 Au NPs immobilization on metal metalloporphyrin networks (AuNPs/MMPF-6(Fe)), 299 301 Au NPs/graphene oxide (Au-NPs/GO), 299 301 Au-based microelectrode, 317 318 Au-Mg micromotor-based platform, 353 Au-NP-MXene. See Nafion-gold nanoparticles-MXene (Au-NP-MXene) Au-Pd/NPSS. See Au and Pd NP-modified nanoporous stainless steel (Au-Pd/NPSS) AuNPs. See Gold nanoparticles (AuNPs) B Bacillus sp., 395 B. altitudinis, 395 B. altitudinis immobilized ND, 395 B. subtilis, 194 Backscattered electron (BSE), 455 457 Band shift, nanothermometers based on, 244 245 Bandpass filters, 206 207 Bandwidth, nanothermometers based on, 246 6-BAP. See 6-Benzylaminopurine (6-BAP) Bare metallic nanoparticles, 79 80 BC. See Black carbon (BC) BChE. See Butyrylcholinesterase (BChE) Benzidine, 87 88 2-(2-Benzothiazolylazo)orcinol (BTAO), 390 6-Benzylaminopurine (6-BAP), 417 420 17β-estradiol, 85 β-nicotinamide adenine dinucleotide (NADH), 311 312 Bifunctional compounds, 396 Bimetallic Au nickel NPs, 299 301 Bio-DLLME, 49 50

Index

Bioanalysis, 43 Biofunctionalization, 313 Biological range of temperature, 229 230 Biomedical electrochemical sensor platforms, 313 Biomolecules, 389 MXenes for detection, 363 365 Bionanomaterials, 317 318 aptamers, 317 318 DNA nanostructures, 318 electrochemical biosensor platforms, 317 Biosensing matrix, 363 365 Biosorption, 395 Biotinylated primary anti-S. aureus aptamer, 345 346 Bis(2-ethylhexyl) phthalate (DEHP), 389 Bis(2-ethylhexyl)phosphinate anion ((BEHPA)2), 83 84 Bismuthiol-II-immobilized SCMNPs, 401 Bisphenol-A (BPA), 83 Black carbon (BC), 449 450, 465 emission factors, 452t Bloch modes, 201 202 Blood air barrier, 439 BMIm. See Butylmethylimidazolium hexafluorophosphate (BMIm) BMP DCA IL. See Butylmethylpyrrolidinium dicyanamide IL (BMP DCA IL) BMP TFSI IL. See Butyl methyl pyrrolidinium bis (trifluoromethanesulfonyl) imide IL (BMP TFSI IL) Boltzmann distribution, 231 232 BoNT/E. See Botulinum neurotoxin type E (BoNT/E) Boron nitride, 361 Bottom-up methods, 4 Botulinum neurotoxin type E (BoNT/E), 280 Bovine serum albumin (BSA), 276 279 BPA. See Bisphenol-A (BPA) BPEI. See Branched cationic polyethyleneimine (BPEI) Branched cationic polyethyleneimine (BPEI), 391 Brazilian legal system, 441 Bromate ions (BrO32), 365 367 (5-Bromo-2-pyridylazo)-5-(diethylamino) phenol, 385

Index

Brownian motion, 477 479 Brucellosis, 304 Bruggeman model, 203 205 BSA. See Bovine serum albumin (BSA) BSE. See Backscattered electron (BSE) BTAO. See 2-(2-Benzothiazolylazo)orcinol (BTAO) Butyl methyl pyrrolidinium bis (trifluoromethanesulfonyl) imide IL (BMP TFSI IL), 304 Butylmethylimidazolium hexafluorophosphate (BMIm), 389 Butylmethylpyrrolidinium dicyanamide IL (BMP DCA IL), 304 Butyrylcholinesterase (BChE), 347, 352 C C-dots. See Carbon dots (C-dots) C18, 58, 81 C60. See Fullerenes (FLNs) C8, 58 CA. See Carbonaceous aerosol (CA) Cadmium oxide, 304 305 Calixarenes, 425 427 Camplyobacter spp., 194 C. jejuni, 193 194 Capillary electrochromatography (CEC), 104 Capillary electrophoresis (CE), 63, 99 100, 131 132 Capillary gel electrophoresis (CGE), 131 132 Capillary isoelectric focusing (CIEF), 131 132 Capillary zone electrophoresis (CZE), 131 132 CAR. See Carboxen (CAR) Carbodiimide cross-linker chemistry, 424 Carbon black (CB), 339 340 Carbon dots (C-dots), 380 Carbon fibers (CFs), 309 Carbon molecular sieve, 66 Carbon nanodots (CNDs), 3, 8 13. See also Graphene quantum dots (GQDs) analytical applications fluorescence systems, 13 20 analytical figures of merit for CNDs-based ferric ion-probing systems, 15t

509

mechanisms of CND-based photoluminescent analytical systems, 20 21 photoluminescent properties of, 10 12 downconversion, 10 12 upconversion, 12 raw carbon sources for, 3 4 spectral properties and chemical stability of, 9 13 structural characteristics, 8 9 synthesis, 4 8, 5f UV Vis spectra, 11f Carbon nanofibers (CNFs), 309, 339 Carbon nanomaterials, 59, 306 313, 317. See also Polymer nanomaterials carbon nanomaterial-based electrochemical methods, 279 280 carbon nanomaterial-based membranes, 160 167 carbon nanotubes-based membranes, 163 166 fullerene-based membranes, 166 167 graphene-based membranes, 160 163 carbon nanotubes, 308 311 electrodes modification with, 276 284 designing of instant protocol and instant catalyst, 282f ITO glass electrodes design with MWCNTs-antibody-AFB1, 277f Nyquist diagrams, 283f graphene, 311 313 Carbon nanostructures, 101 104 Carbon nanotubes (CNTs), 45, 58, 101, 104, 194, 308 311, 329 331, 335 339, 368 369, 379 CNT-based membranes, 163 166 electrochemical carbon nanotube-based (bio)sensors, 335 336 optical carbon nanotube-based (bio) sensors, 336 339 Carbon NPs, 400 Carbon paste (CP), 301 Carbon quantum dots. See Carbon dots (Cdots) Carbon-based materials, 339 342 carbon-based materials in electrochemical biosensors, 339 340 carbon-based materials in optical biosensors, 340 342

510

Carbon-based nanomaterials, 3, 35, 45, 379 395, 398 functionalization covalent functionalization, 380 389 noncovalent functionalization, 389 395 Carbon-based NPs, 127 129 Carbonaceous aerosol (CA), 449 analytical characterization techniques, 451 465 microscopic techniques, 454 460 spectroscopy techniques, 460 465 direct and indirect climate effect, 455f importance of nanoscale characterization, 451 and source, 449 451 Carbonaceous-based entities, 342 343 Carboxen (CAR), 63 65 Carboxyfluorescein-DNA macro-molecules, 19 20 Carboxyl-coated MNPs, 137 138 Carboxylated carbon nano-spheres, 51 Carboxylated MWCNTs, 381 382 Carboxylic groups, 345 Carcinoembryonic antigen (CEA), 496 497 Carmine, 16 17 Cartap, 424 Cation-exchange resin, 59 63 Cations, 13 16 copper ions, 16 ferric ions, 14 heavy metal ions, 16 mercury ions, 14 15 Cavity ringdown spectroscopy (CRDS), 464 465 CB. See Carbon black (CB) CE. See Capillary electrophoresis (CE) CEA. See Carcinoembryonic antigen (CEA) CEC. See Capillary electrochromatography (CEC) Centrifugation, 480 Ceramic membranes, 159 160 Cerium oxide, 106 107, 304 305 Cerium oxide nanomaterials, 305 Certification, Labeling and Packaging Regulation (CLP Regulation), 441 442 Cetyltrimethylammonium bromide (CTAB), 420 422 CF microelectrodes (CFEs), 314 316 CFEs. See CF microelectrodes (CFEs)

Index

CFs. See Carbon fibers (CFs) CGE. See Capillary gel electrophoresis (CGE) Chemical analysis, 30 31 Chemical defect functionalization, 387 Chemical precursors, 3 Chemical vapor deposition (CVD), 207 209 Chitosan (CS), 309 310 chitosan-based nanocomposite membranes, 169 chitosan/zinc oxide NP-based membrane, 127 129 NP-based membrane, 127 129 Chlorogenic acid, 85 86 Chlorophenols (CPs), 382 (3-Chloropropyl)-trimethoxysilane, 383 Chlorothalonil, 424 Cholera toxin (CT), 276 279 Choline chloride, 394 Chromatography, 99 100, 133 135, 276 279 gas chromatography, 134 135 liquid chromatography, 133 134 CIEF. See Capillary isoelectric focusing (CIEF) Circulating tumor cells (CTCs), 136 137 Cit-capped Ag NPs. See Citrate-capped Ag NPs (Cit-capped Ag NPs) Citrate-capped Ag NPs (Cit-capped Ag NPs), 417 420 CitrateAu NPs (Cit-Au NPs), 422 424 Citrus limon, 7 8, 10 12, 16 17 Citrus sinensis, 7 8, 10 12 Civil Code, 441 CK. See Creatine kinase (CK) CK-MB biomarker. See Creatine kinase-MB biomarker (CK-MB biomarker) Clogging, 127 Clostridium difficile toxin B (Tcd B), 276 279 Cloud-point extraction (CPE), 34 35 CLP Regulation. See Certification, Labeling and Packaging Regulation (CLP Regulation) CNDs. See Carbon nanodots (CNDs) CNFs. See Carbon nanofibers (CNFs) CNSs-COOH. See Carboxylated carbon nano-spheres (CNSs-COOH)

Index

CNT-based nanocomposite membranes, 165 166 CNT-coated niobium (CNT-Nb), 309 CNTs. See Carbon nanotubes (CNTs) Cobalt oxide (Co3O4), 302, 304 305 Colorimetric assays, 342 343, 349 350, 353 354, 422 424 Colorimetric recognition of pesticides by surface-modified Ag nanoparticles, 416 420 by surface-modified Au nanoparticles, 420 429 Conducting polymers (CPs), 313 316 Conductive organic materials, 45 Consumer Defense Code, 441 Contactless nanomanometers, 227 Continuous wave (CW), 247 Control electron-transport mechanism, 297 Conventional sample preparation approaches, 75 Conventional solid-phase extraction, 129 Copper, 106 Cu(I)-catalyzed click chemistry, 420 422 Copper nanoparticles (CuNPs), 106, 346 non-carbonaceous nanomaterials electrochemical (bio)sensors, 346 347 optical (bio)sensors, 350 351 Copper oxide, 304 305, 399 nanomaterials, 305 Coprecipitation technique, 77 Core-shell layers, 45 Coupling immunoassay techniques, 497 Covalent functionalization of carbon-based nanomaterials, 380 389 Covalent immobilization, 132 CP. See Carbon paste (CP) CPE. See Cloud-point extraction (CPE) CPs. See Chlorophenols (CPs); Conducting polymers (CPs) CRDS. See Cavity ringdown spectroscopy (CRDS) Creatine kinase (CK), 317 318 Creatine kinase-MB biomarker (CK-MB biomarker), 317 318 Crosscutting technologies, 329 Crystallinity of nanomaterials, 483 CS. See Chitosan (CS) CT. See Cholera toxin (CT)

511

CTAB. See Cetyltrimethylammonium bromide (CTAB) CTCs. See Circulating tumor cells (CTCs) CuS nanoparticle-decorated graphene (CuS/ GO), 332 Custom-make strategic DNA-based sensing principles, 334 CV. See Cyclic voltammetric (CV) CVD. See Chemical vapor deposition (CVD) CW. See Continuous wave (CW) Cyclic olefin copolymers, 187 Cyclic voltammetric (CV), 276 279 L-Cysteine functionalized Au NPs, 427 429 CZE. See Capillary zone electrophoresis (CZE) D DA. See Dopamine (DA) DAC. See Diamond anvil cell (DAC) DCC. See N,N-Dicyclohexylcarbodiimide (DCC) DCF. See Diclofenac (DCF) DCP. See 2,9-dicarboxyl-1,10phenanthroline (DCP) Deceptive quenching, 21 Deep eutectic solvents (DESs), 392, 394 DEHP. See Bis(2-ethylhexyl) phthalate (DEHP) Demeton pesticides, 420 422 Dendrimers, 313 314 Density functional theory, 370 DES. See Diethylstilbestrol (DES) DESs. See Deep eutectic solvents (DESs) Detection geometry, 255 256 Diafenthiuron, 424 425 Dialysis membrane, 108 127 Diamond anvil cell (DAC), 235 chamber, 253 Diamonds, 254 255 2,9-dicarboxyl-1,10-phenanthroline (DCP), 348 349 Dichalcogenides, 361 Dichlorvos, 420 422 Diclofenac (DCF), 80 81, 81f N,N-Dicyclohexylcarbodiimide (DCC), 385 386 Diethylstilbestrol (DES), 85, 309 310 Differential pulse voltammetry (DPV), 284 285, 332

512

5,7-Dimethoxycoumarin, 389 1,5-Diphenylthiocarbazone, 385 Dipicolinic acid (DPA), 388 389 Dispersed Cit-Au NPs, 422 424 Dispersive liquid-liquid microextraction (DLLME), 49 50 Dispersive solid-phase extraction (dSPE), 46, 58 59, 107 108, 130, 381 382 Dispersive solid-phase microextraction (DSPME), 48 50 Dithiocarbamate-p-tertbutylcalix[4] arene (DTC-PTBCA), 424 425 Dithiocarbamates, 424 425 Dithizone, 385 Divinylbenzene (DVB), 63 65 DLLME. See Dispersive liquid-liquid microextraction (DLLME) DLS. See Dynamic light scattering (DLS) DNA, 331 facilitating amplified sensor, 318 fragmentation, 438 nanostructures, 318 DNA/RNA sensors, 497 498 Dopamine (DA), 301, 363 365 Double-band ratio nanothermometers, 236 243 Double-stranded DNA (ds DNA), 332 333 Double-walled CNTs (DWCNTs), 379 Downconversion, 10 12 DOX. See Doxorubicin (DOX) DOX GQD FA nano-assembly, 498 499 Doxorubicin (DOX), 498 499 DPA. See Dipicolinic acid (DPA) DPV. See Differential pulse voltammetry (DPV) Draw/eject mode, 46 Drude model, 203 205 Drug delivery systems, 498 499 and multicenter nanothermometers, 243 244 ds DNA. See Double-stranded DNA (ds DNA) dSPE. See Dispersive solid-phase extraction (dSPE) DSPME. See Dispersive solid-phase microextraction (DSPME) DTC-PTBCA. See Dithiocarbamate-ptertbutylcalix[4] arene (DTC-PTBCA)

Index

Dual signal-tagged hairpin-structured DNAbased ratiometric probe (dhDNA-based ratiometric probe), 318 DVB. See Divinylbenzene (DVB) DWCNTs. See Double-walled CNTs (DWCNTs) Dy31, 239 Dynamic light scattering (DLS), 477 480 Dynamic quenching, 21 E EC. See Elemental carbon (EC) ECD. See Gas chromatography electron capture detector (ECD) ECHA. See European Chemicals Agency (ECHA) ECL sensor. See Electroluminescent sensor (ECL sensor) ED electron probe X-ray microanalysis (EPMA), 462 463 EDC. See N-Ethyl-Nʹ-(3dimethylaminopropyl)-carbodiimide (EDC) EDS. See Energy-dispersive spectroscopy (EDS) EDTA. See Ethylenediamine triacetic acid (EDTA) EDX spectroscopy. See Energy-dispersive X-ray spectroscopy (EDX spectroscopy) EDXRF. See Energy dispersive X-ray fluorescence spectrometry (EDXRF) EELS. See Electron energy loss spectroscopy (EELS) EFs. See Enrichment factors (EFs) EIS. See Electrochemical impedance spectroscopy (EIS) Elastomeric materials, 186 187 Electrocatalytic metal encapsulation, 346 347 Electrochemical biosensors, 297 298 carbon-based materials, 339 340 carbon nanotube-based (bio)sensors, 335 336 creatinine sensor, 316 317 deposition, 391, 398 DES sensor, 309 310 graphene-based (bio)sensors, 332 333 ion-selective electrochemical sensor, 333f

Index

immunosensors, 318, 345 346, 496 497, 496f magnetoimmunosensor, 288 nanoporous photonic crystal structures NAA, 203 207 NAA-DBRs, 209 213 NAA-GIFs, 213 216 NAA-optical μCVs, 216 218 NAA-PC as optical sensing platforms, 207 219 structural engineering of nanoporous photonic crystals, 202f sensing of mycotoxins, 276 288 Electrochemical (bio)sensors, noncarbonaceous nanomaterials AgNPs, 345 346 AuNPs, 343 344 Cu nanoparticles and Pt nanoparticles, 346 347 inorganic nanoparticles, 347 348 Electrochemical impedance spectroscopy (EIS), 280 Electrochemically reduced graphene oxide (ERG), 311 312 Electrodepositing CuNPs, 346 Electrodes modification with carbon nanomaterials, 276 284 with metal NPs, 284 288 Electrogenerated chemiluminescence biosensor, 299 301 Electroless deposition, 207 209, 398 Electroluminescent sensor (ECL sensor), 365 Electron energy loss spectroscopy (EELS), 458 459 Electron microscopy, 454 455 Electroosmotic flow (EOF), 100, 188 Electrophoresis light scattering coupled with phase analysis light scattering (ELS PALS), 477 479 Electrophoretic techniques, 99 100 Electrothermal atomic absorption spectrometer (ETAAS), 384, 386 Elemental carbon (EC), 449 450, 465 ELISA technique, 194 195 ELSI. See Ethical, legal, social issues (ELSI) ELS PALS. See Electrophoresis light scattering coupled with phase analysis light scattering (ELS PALS)

513

Energy dispersive X-ray fluorescence spectrometry (EDXRF), 384 Energy transfer upconversion (ETU), 228 Energy-dispersive spectroscopy (EDS), 162, 457 458 Energy-dispersive X-ray spectroscopy (EDX spectroscopy), 457 458 scanning electron microscopy with, 455 458 transmission electron microscopy with, 458 459 “Engines of Creation” (Drexler), 32 Enrichment factors (EFs), 377 Enterobacter sakazakii, 193 194 Enteromorpha prolifera, 4 6, 14 Environmental scanning electron microscope (ESEM), 458 Enzymes, 331 enzyme-based signal amplification, 318 EOF. See Electroosmotic flow (EOF) EPMA. See ED electron probe X-ray microanalysis (EPMA) Er31, 239 241 ERG. See Electrochemically reduced graphene oxide (ERG) Eriochrome black T, 385 Escherichia coli, 136, 167 168, 194, 345, 395 O157: H7, 193 194 O157:H7. 16, 334 335 ESEM. See Environmental scanning electron microscope (ESEM) Estrogens, 85 Estrone, 85 ETAAS. See Electrothermal atomic absorption spectrometer (ETAAS) Ethanol (C2H5OH), 367 368 Ethical, legal, social issues (ELSI), 437 Ethyl parathion, 427 429 N-Ethyl-Nʹ-(3-dimethylaminopropyl)carbodiimide (EDC), 276 279 Ethylenediamine, 385 Ethylenediamine triacetic acid (EDTA), 386 Ethylenediaminetetraacetic acid, 385 ETU. See Energy transfer upconversion (ETU) EU-NCL. See European NCL (EU-NCL) Eu31, 238

514

European Agency for Safety and Health at Work, 440 European Chemicals Agency (ECHA), 441 European NANoREG project, 441 European NCL (EU-NCL), 477 479 Excitation light, source of, 255 F FA. See Folic acid (FA) FAAS analysis. See Flame atomic absorption spectrometer analysis (FAAS analysis) Fabricated biosensor, 299 301 Fabricated electrode, 282 284 Fabricated MIP-modified membraneprotected MWCNTs, 388 Fabricated nano-assembly, 498 499 Fabricated polypyrrole-silver nanocomposite, 399 Fabricated sensor, 368 369 Facile analytical methods, 415 FB1. See Fumonisin B1 (FB1) Fc-sP. See Ferrocene-labeled signal probe (Fc-sP) Fe3O4 synthesis, 77 Fe3O4@PPy magnetic NPs, 49 50 Ferric ions, 14 Ferrocene-labeled signal probe (Fc-sP), 318 FESEM. See Field-emission scanning electron microscope (FESEM) FET sensor. See Field effect transistor sensor (FET sensor) FFF. See Field-flow fractionation (FFF) Fibrillated mesoporous carbon (FMC), 51 FID. See Flame ionization detection (FID) Field effect transistor sensor (FET sensor), 363 365 Field-emission scanning electron microscope (FESEM), 455 457, 458f Field-flow fractionation (FFF), 477 479 FIR. See Fluorescence intensity ratio (FIR) Flame atomic absorption spectrometer analysis (FAAS analysis), 386 Flame ionization detection (FID), 385 FLNs. See Fullerenes (FLNs) Florisil, 58 Flow injection synthesis, 78 79 Fluorescence, 336 Fluorescence intensity ratio (FIR), 231 Fluorescence resonance emergency transference (FRET), 496 497

Index

Fluorine, 361 362 FMC. See Fibrillated mesoporous carbon (FMC) Focused laser beam, 229 230 Folic acid (FA), 498 499 Food samples AFB1 in, 279 282 mycotoxins in, 276, 284 OTA in, 281 282 Fo¨rster resonance energy transfer (FRET), 21, 340 Fourier-transform infrared spectroscopy (FTIR spectroscopy), 384, 387 388, 462 463 Free-radical polymerization, 399 FRET. See Fluorescence resonance emergency transference (FRET); Fo¨rster resonance energy transfer (FRET) FTIR spectroscopy. See Fourier-transform infrared spectroscopy (FTIR spectroscopy) Fullerenes (FLNs), 45, 102 103, 379 fullerene-based membranes, 166 167 polysiloxane. See Fullerol Fullerol, 385 Fumonisin B1 (FB1), 279 Functional CNDs, 4 Functional groups, 424 Functional nanomaterials, 276, 297 bionanomaterials, 317 318 carbon nanomaterials, 306 313 functional nanomaterial-based electrodes, 297 metal oxide nanomaterials, 304 306 noble metallic NPs, 299 304 polymer nanomaterials, 313 317 Functional Pt nanomaterial-based sensor platforms, 302 Functionalization method, 386 387 Functionalized carbon nanomaterials, 306 308 Functionalized nanomaterials classification of nanomaterials, 378f production and functionalization of NMs, 377 379 for sample preparation methods carbon-based nanomaterials, 379 395 magnetic nanomaterials, 400 402 metallic and metal-oxide nanomaterials, 395 399

Index

G Gallium, 106 107 γ-mercaptopropyltrimethoxysilane-modified silica-coated magnetic NPs (SCMNPs), 401 Gas chromatography (GC), 63, 99 100, 134 135, 185 186, 276 Gas chromatography electron capture detector (ECD), 381 382 Gas chromatography mass Spectrometry (GC MS), 377 Gaseous molecules detection, MXene for, 367 368 GC. See Gas chromatography (GC) GCE. See Glassy carbon electrode (GCE) GC MS. See Gas chromatography mass Spectrometry (GC MS) Gd31, 238 239 Genosensors, 318 Geobacillus thermoleovorans, 395 Geobacillus toebii, 395 Glass-based μTAS platforms, 187 Glassy carbon electrode (GCE), 276 279, 363 365, 497 Glucose oxidase, 302, 363 365 Glucose sensor, 305 Glucose-binding protein, 336 338 Glycated hemoglobin (HbA1c), 299 301 GMs. See Graphene-based materials (GMs) GNS. See Graphene nanosheets (GNS) GO. See Graphene oxide (GO) Gold, 106, 284 285, 299 nanoparticles, 299 301 Gold nanoparticles (AuNPs), 106, 165, 287 288, 329 331, 398 399, 415, 420 422, 425 427, 497 Au NPs based colorimetric sensing platforms, 427 429 Au-NPs/rGO-based sensor, 311 312 non-carbonaceous nanomaterials electrochemical (bio)sensors, 343 344 non-carbonaceous nanomaterials optical (bio)sensors, 348 349 pDA polyethyleneimine nanocomposite membranes, 167 168 Gold nanorods (Au NRs), 420 422 GONs. See Graphene oxide nanosheets (GONs) GQDs. See Graphene quantum dots (GQDs)

515

Grapheme, 45 Graphene, 58, 104, 134 135, 276 280, 311 313, 329 335, 380 electrochemical graphene-based (bio) sensors, 332 333 Flagship, 329 331 graphene-based membranes, 160 163 graphene-based MNPs, 130 graphene-based nanohybrid, 493 494 graphene-like materials, 400 optical graphene-based biosensors, 333 335 Graphene nanosheets (GNS), 280 Graphene oxide, 45, 58, 82 83, 104, 161, 276 280, 332, 379 GO@MIP composite, 388 389 GO-based nanocomposite membrane, 162, 162f GO-MWCNTs-based nanocomposite membrane, 162 163 Graphene oxide nanosheets (GONs), 332 Graphene quantum dots (GQDs), 309 310, 493. See also Carbon nanodots (CNDs) GQD-based nanomaterials, 493 494 GQD based platforms for drug delivery, 498 500 GQDs-based nanocomposites in drug delivery, 499f for in vitro biomarkers detection, 495 498 GQD based immunological assay, 495 497 GQD based nucleic acid assay, 497 498 for in vivo imaging, 498 perspectives, 501 502 preparation and properties, 494 495, 494f researches on toxicity, 500f toxicity research of, 500 501 Graphene-based materials (GMs), 127 129 Green extraction solvents, 392 H Hafnia alvei, 194 Hafnium, 50 Hafnium oxide, 106 107 Halloysite nanotubes (HNTs), 162 Hb-nafion-MXene-modified GCE sensor, 363 365

516

HbA1c. See Glycated hemoglobin (HbA1c) HBDs. See Hydrogen bond donors (HBDs) HBI-DTC. See Hydroxy benzylindoledithiocarbamate (HBI-DTC) Headspace-SPME (HS-SPME), 63 Heavy metal ions, 16 Height equivalent to theoretical plate (HETP), 100 Hemaglutinin-based electrochemical biosensors, 318 Hemoglobin-immobilized Ti3C2 (Hbimmobilized Ti3C2), 363 365 Heteroatoms, 3 4, 9 Heterogeneous molecular nanosystems, 33 HETP. See Height equivalent to theoretical plate (HETP) 1-Hexadecyl-3-methylimidazolium bromide (C16mimBr), 393 1-Hexadecyl-3-methylimidazolium bromidecoated Fe3O4 magnetic NPs (C16mimBrcoated Fe3O4 magnetic NPs), 401 Hexylmethylimidazolium hexafluorophosphate (HMIm), 389 HF. See Hollow fiber (HF) High-energy electrons, 455 457 light source, 229 230 High-performance liquid chromatography (HPLC), 99 100, 276, 377 High-performance liquid chromatography ultraviolet (HPLC-UV), 382 High-pressure luminescence measurements, 254 258 detection geometry, 255 256 diamonds, 254 255 pressure determination, 256 258 source of excitation light, 255 measurements, 253 254 pressure chamber, 253 pressure-transmitting medium, 253 254 High-resolution TEM (HRTEM), 458 459 HILIC. See Hydrophilic interaction LC mode (HILIC) HLB. See Hydrophilic-lipophilic balance (HLB) HMIm. See Hexylmethylimidazolium hexafluorophosphate (HMIm)

Index

HMNP-DTC. See 4-Hydroxy-6-methyl-3nitro-2-pyridone-dithiocarbamate (HMNPDTC) HNTs. See Halloysite nanotubes (HNTs) Ho31, 239 Hollow fiber (HF), 51 Horseradish peroxidase (HRP), 279 280 Hot embossing, 186 187 HPLC. See High-performance liquid chromatography (HPLC) HPLC-UV. See High-performance liquid chromatography ultraviolet (HPLC-UV) HPV. See Human papillomavirus (HPV) HRP. See Horseradish peroxidase (HRP) HRTEM. See High-resolution TEM (HRTEM) HS-SPME. See Headspace-SPME (HSSPME) HSA. See Human serum albumin (HSA) Human papillomavirus (HPV), 350 Human serum albumin (HSA), 215 216 Hydrogen bond donors (HBDs), 394 Hydrogen peroxide, 6 7, 17 18, 301, 347, 420 422 Hydrolysis, 78 Hydrophilic interaction LC mode (HILIC), 134 Hydrophilic-lipophilic balance (HLB), 58, 63 65 Hydrothermal synthesis, 78, 397 Hydroxy benzylindoledithiocarbamate (HBIDTC), 424 425 4-Hydroxy-6-methyl-3-nitro-2-pyridonedithiocarbamate (HMNP-DTC), 424 425 Hydroxyl, 361 362 Hydroxyl-terminated PDMS (PDMS-OH), 401 Hydroxylamine sensor, 299 301 8-Hydroxyquinoline, 385 N-Hydroxysuccinimide (NHS), 276 279 I ICPOES analysis. See Inductively coupled plasma optical emission spectrometry analysis (ICPOES analysis) IL-coated magnetic GO NPs, 394 IL-functionalized graphene, 393 ILs. See Ionic liquids (ILs) 2,2ʹ-Iminodiacetic acid, 386

Index

Immersion SPME, 63 Immunosensors, 194, 282 284, 318, 495 497 amperometric, 497 electrochemical, 496 497, 496f In situ chemical oxidation, 397 In situ electrochemical polymerization method, 391 In-tube solid-phase microextraction (ITSPME), 46 48 in draw/eject and in-valve mode, 46, 48f IT-SPME-NanoLC, 46 48 preparation, 49f In-valve mode, 46 Indium tin oxide (ITO), 276 279, 277f Inductively coupled plasma optical emission spectrometry analysis (ICPOES analysis), 385 386, 401 Infrared spectroscopy (IR spectroscopy), 459 460 Ink-print technology, 186 187 Inorganic materials, 331 and mixed polymers, 45 nanoparticles, 347 348 NMs, 377 silica NPs, 105 106 Interfacial reactivity, 473 International Council on Harmonization of Technical Requirements for Registration of Pharmaceuticals, for Human Use, 477 479 International Standardization Organization (ISO), 441, 477 certification for nanomaterials, 442 standards for characterization of nanomaterials, 478t Intralipid liquid, 246 Intrinsic SWCNT fluorescence intensity, 338 Ion-exchange materials, 81 Ionic liquid-derived nano-FMC, 51 Ionic liquids (ILs), 107, 389 IR spectroscopy. See Infrared spectroscopy (IR spectroscopy) Iridium oxide NPs, 347 348 Iron, 106 107 Iron oxide, 304 305 ISO. See International Standardization Organization (ISO)

517

IT-SPME. See In-tube solid-phase microextraction (IT-SPME) ITO. See Indium tin oxide (ITO) L LA. See Lipoic acid (LA) Lab-on-a-chip devices, 189 systems, 36 Label-free amperometric immunosensor, 287 ultrasensitive amperometric immunosensor, 288 Lanthanide-based luminescent nanoparticles (Ln31-based luminescent nanoparticles), 227 Lanthanide-based pressure sensors, 257 258 Laporte selection rules, 228 Laser pyrolysis, 79 Law of conservation of mass, 30 31 Layer-by-layer deposition (LbL), 207 209, 397 Layer-by-layer synthesized NDs, 134 LC. See Liquid chromatography (LC) LC MS. See Liquid chromatography mass spectrometry (LC MS) LC MS MS. See Liquid chromatography tandem mass spectrometer (LC MS MS) Leucine-arginine (LR), 276 279 Lifetime nanothermometers, 247 Lifetime thermal coefficients, 247 Ligand exchange reactions, 424 Limit of quantification (LOQ), 381 382 Limits of detection (LODs), 14, 59 63, 80, 130 131, 381 382, 417 420 Lipoic acid (LA), 420 422 Liquid chromatography (LC), 63, 99 100, 133 134 Liquid chromatography mass spectrometry (LC MS), 377 Liquid chromatography tandem mass spectrometer (LC MS MS), 377 Liquid-phase deposition (LPD), 396 398 Liquid liquid extraction (LLE), 57 58, 75 LIR. See Luminescence intensity ratio (LIR) Listeria innocua, 194 Listeria monocytogenes, 193 194 LLE. See Liquid liquid extraction (LLE)

518

LLoD. See Low limit of detection (LLoD) Ln21/31-doped materials, 228 229 Ln31-based luminescent nanoparticles. See Lanthanide-based luminescent nanoparticles (Ln31-based luminescent nanoparticles) Localized SPR (LSPR), 201, 420 LODs. See Limits of detection (LODs) Longpass filters, 206 207 Loop-mediated isothermal amplification, 194 Looyenga-Landau-Lifshitz model, 203 205 LOQ. See Limit of quantification (LOQ) Lorentz-Lorenz model, 203 205 Low limit of detection (LLoD), 209 211 Low signal-to-noise ratio, 230 LPD. See Liquid-phase deposition (LPD) LR. See Leucine-arginine (LR) LSPR. See Localized SPR (LSPR) Luminescence intensity ratio (LIR), 231 M m-MIP NPs. See Magnetic MIP NPs (m-MIP NPs) MAA. See Methacrylic acid (MAA) Maghemite (γ-Fe2O3), 107 108, 130 Magnesium oxide, 106 107 Magnetic beads, 329 331 Fe3O4 nanoparticles, 78 79, 88 89 Fe3O4@TbBd nanocomposite, 87 88, 88f Fe3O4/SiO2 nanoparticles, 86, 89 Fe3O4/SiO2/dithiocarbamate nanoparticles, 80 Fe3O4/ZrO2 nanoparticles, 80 lignin based carbon nanoparticles, 81 metal nanoparticles, 76 77 nanomaterials, 306, 400 402 Magnetic MIP NPs (m-MIP NPs), 402 Magnetic nanoparticles (MNPs), 45, 75 76, 107 108, 400 solid-phase extraction, 79 synthesis, 76 79 Magnetic solid-phase extraction (MSPE), 49 50, 58 59, 79 89, 130, 393 394, 400 for biological samples, 86 89 for environmental samples, 80 84 for food and beverage samples, 85 86 Magnetite (Fe3O4), 107 108, 130, 402

Index

MALDI. See Matrix-assisted laser desorption/ionization (MALDI) Manganese oxide, 304 305 Mass spectrometry (MS), 130, 276 279, 383 Material science, application in, 138 139 Mathamidophos, 422 424 Matrix solid-phase dispersion (MSPD), 57 58, 65 66 Matrix-assisted laser desorption/ionization (MALDI), 383 MAX. See Mixed-mode/anion exchange (MAX) Maxwell-Garnett model, 203 205 MB-rP. See Methylene blue-altered internal orientation probe (MB-rP) MC. See Microcystin (MC) MCM-41, 66 MCM-48, 66 MCX. See Mixed-mode/cationic exchange (MCX) MEKC. See Micellar electrokinetic chromatography (MEKC) Melamine biosensor, 318 Membrane, 159 applications of nanomaterials applications of nanomaterial-based composite membranes, 173t carbon nanomaterial-based membranes, 160 167 molecularly imprinted polymer-based membranes, 169 174 nanoparticle-based membranes, 167 169 traditional membranes, 159 160 fouling, 127 membrane-based separation, 108 129 separation, 159 MEPS. See Microextraction by packed syringe (MEPS) 1-(2-mercaptoethyl)-1,3,5-triazinane-2,4,6trione (MTT), 348 3-(Mercaptopropyl)-trimethoxysilane (MPTMS), 209 211 11-Mercaptoundecanoic acid (11-MUA), 218 219 Mercury ions, 14 15 MERS-CoV. See Middle East respiratory syndrome coronavirus (MERS-CoV)

Index

Mesoporous carbon (MSC), 279 280 Metabolite separation, application in, 138 Metal ions, 13 16 click chemistry approach, 420 422 Metal nanoparticles (MNPs), 106, 134, 284, 395 396, 415, 435 electrodes modification with, 284 288 electrodes modification based on adsorption mechanism, 284 285 molecular assembly on metal and metal oxide NP surfaces, 285 288 nanomaterial-integrated electrochemical analytical techniques, 289t Metal oxides, 400 nanomaterials, 304 306, 317 cerium oxide nanomaterials, 305 copper oxide nanomaterials, 305 magnetic nanomaterials, 306 nanoparticles, 106 107, 304 305, 397 Metal-organic frameworks (MOFs), 45, 58, 101, 107, 346, 402 MOF-199, 59 MOF-MIP, 66 Metal-oxide nanomaterials, 395 399 functionalization chemical functionalization, 396 by electroless and electrochemical deposition, 398 by in situ chemical oxidation, 397 by liquid-phase deposition, 397 398 by potentiostatic anodization, 398 399 by solvothermal synthesis, 397 surface functionalization via interactions, 397 Metallic nanomaterials (metallic NMs), 106, 395 399 functionalization, 396 399 chemical functionalization, 396 by electroless and electrochemical deposition, 398 by in situ chemical oxidation, 397 by liquid-phase deposition, 397 398 by potentiostatic anodization, 398 399 by solvothermal synthesis, 397 surface functionalization via interactions, 397 Metallic/metallic oxide nanoparticles, 44 2-(Methacrylamido) ethyl methacrylate, 402 Methacrylic acid (MAA), 82, 105, 387 388

519

3-Methacryloxypropyltrimethoxysilane, 383, 396 Methyl mercury, 82 N,N-Methylene bisacrylamide, 388 389 Methylene blue-altered internal orientation probe (MB-rP), 318 Metsulfuron-methyl, 424 425 MF. See Microfiltration (MF) Mg-Au-Ni Janus microengines, 352 353 MgO. See Magnesium oxide (MgO) Micellar electrokinetic chromatography (MEKC), 131 132 Micro manufacturing, 186 187 Micro total analysis systems (μTAS), 185 advantages and disadvantages, 188 applications, 188 195, 190t analysis of environmental samples, 189 193 analysis of food samples, 193 195 components, 186 188, 186f Microchip capillary electrophoresis, 132 Microcontact printing, 186 187 Microcrystals, 258 Microcystin (MC), 276 279 Microelectromechanical systems, 36 Microemulsion-based synthesis, 78 Microengines, 352 353 Microextraction by packed sorbent. See Microextraction by packed syringe (MEPS) Microextraction by packed syringe (MEPS), 46, 50 51, 57 58 Microextraction methods, nanomaterials application in, 46 52 dispersive solid-phase microextraction, 48 50 in-tube solid-phase microextraction, 46 48 microextraction by packed syringe, 50 51 molecularly imprinted polymer nanomaterials in, 52 nanofibers as sorbent in, 51 stir bar sorptive extraction, 51 supramolecular solvent microextraction, 50 Microfiltration (MF), 109 Microfluidic aptamer-based electrochemical biosensor, 317 318

520

Microfluidic paper-based analytical platforms (μPAD). See Paper-based μTAS platforms Microfluidics, 136 Microinjection molding, 186 187 Micromachined polycarbonate-based disposable chip, 189 Micromilling, 186 187 Micromotors, 352 354 Microscopic techniques for CA, 454 460 Microtransfer molding, 186 187 Microwave treatment, 8 Microwave-assisted surface functionalization method, 383 Middle East respiratory syndrome coronavirus (MERS-CoV), 350 Miniaturization of analytical systems, 185 MIP-MSPD method. See Molecularly imprinted polymer-matrix solid-phase dispersion method (MIP-MSPD method) MIPs. See Molecularly imprinted polymers (MIPs) MIPs-GO. See Molecularly imprinted polymer-coated magnetic graphene oxide (MIPs-GO) MISPE. See Molecularly imprinted polymerphase extraction (MISPE) Mixed metallic NPs, 44 Mixed-mode/anion exchange (MAX), 58 Mixed-mode/cationic exchange (MCX), 58 MNPs. See Magnetic nanoparticles (MNPs); Metal nanoparticles (MNPs) Modified Na-Mont substrate, 288 MOFs. See Metal-organic frameworks (MOFs) Molecular-sieve-based sorbent, 66 Molecularly imprinted polymer-coated magnetic graphene oxide (MIPs-GO), 59 Molecularly imprinted polymer-matrix solidphase dispersion method (MIP-MSPD method), 66 Molecularly imprinted polymer-phase extraction (MISPE), 81 Molecularly imprinted polymers (MIPs), 45, 58 59, 66, 81 82, 105, 313, 316 317, 387 388 MIP-based carboxylated cellulose nanocrystals, 82

Index

MIP-based GO/polyvinylidene fluoride nanocomposite membranes, 172 MIP-based magnetic GO/chitosan nanocomposite, 82 83 MIP-based membranes, 169 174 nanomaterials in microextraction techniques, 52 Monecke model, 203 205 Monolayer-protected AuNPs, 135 MonoTips, 79 Motion and physical stimuli detection, MXene for, 368 369 MPS 2. See MultiPurpose Sampler (MPS 2) MPTMS. See 3-(Mercaptopropyl)trimethoxysilane (MPTMS) MQDs. See MXene-based quantum dots (MQDs) MS. See Mass spectrometry (MS) MSC. See Mesoporous carbon (MSC) MSPD. See Matrix solid-phase dispersion (MSPD) MSPE. See Magnetic solid-phase extraction (MSPE) MTB. See Mycobacterium tuberculosis (MTB) MTEOS. See Trimethoxymethylsilane (MTEOS) MTT. See 1-(2-mercaptoethyl)-1,3,5triazinane-2,4,6-trione (MTT) 11-MUA. See 11-Mercaptoundecanoic acid (11-MUA) MUC1. See Mucin 1 (MUC1) Mucin 1 (MUC1), 318 Multi-chromatic lateral flow assay, 350 Multi-walled carbon nanotubes (MWCNTs), 45, 59, 87, 104, 130 131, 276 279, 306 308, 335 336, 379 multiwalled CNTs-reduced GONs, 346 MWCNTs-Al2O3-based nanocomposite membranes, 164 MWCNTs/PVA cryogel composite, 129 packed columns, 134 135 Pebax-poly(sulfone) nanocomposite membrane, 164 polyaniline-poly(vinylidene fluoride) nanocomposite membranes, 163 164 Multicolor nanoprobe, 420 422 Multifunctional GQDs, 498 499

Index

Multiple bead-based fluidic system, 193 194 MultiPurpose Sampler (MPS 2), 63 65 MWCNT-zirconium oxide nanocomposite materials (MWCNTs-ZrO2), 399 MWCNTs. See Multi-walled carbon nanotubes (MWCNTs) MWCNTs coated with PPy and redox PAMAM (MWCNTs-PPy-PAMAM), 313 314 MWCNTs-COOH. See Carboxylated MWCNTs (MWCNTs-COOH) MWCNTs-COOH/PDMS. See MWCNTsCOOH/polydimethylsiloxane (MWCNTsCOOH/PDMS) MWCNTs-COOH/polydimethylsiloxane (MWCNTs-COOH/PDMS), 382 MWCNTs-PPy-PAMAM. See MWCNTs coated with PPy and redox PAMAM (MWCNTs-PPy-PAMAM) MXene-based quantum dots (MQDs), 365 MXene-based sensors and biosensors, 363 370, 364t for biomolecules detection, 363 365 for environmental contaminants detection, 365 367 for gaseous molecules detection, 367 368 for motion and physical stimuli detection, 368 369 for terahertz sensing, 370 MXene-modified electrodes, 363 365 Mycobacterium tuberculosis (MTB), 313 314, 350 Mycotoxins, 275 276 surface modification of electrodes for electrochemical sensing, 276 288 with carbon nanomaterials, 276 284 with metal nanoparticles, 284 288 N N,S-(co)doping, 9 N,S-doped CNDs, 8 N-doped carbon nanodots (N-doped CNDs), 4 7, 9 N-doped CNDs. See N-doped carbon nanodots (N-doped CNDs) N-GQDs. See Nitrogen-doped GQDs (N-GQDs)

521

NAA. See Nanoporous anodic alumina (NAA) NAA-apodized DBRs (Apo-NAA-DBRs), 206 207, 211 212 NAA-apodized GIFs (Apo-NAA-GIFs), 206 207 NAA-bandpass filters (NAA-BPFs), 206 207 NAA-distributed Bragg reflectors (NAADBRs), 206 207, 209 213 characteristic nanoporous geometry, anodization profile, and optical properties, 209f integrated optical sensing systems, 210f NAA-gradient-index filters (NAA-GIFs), 206 207, 213 216 characteristic nanoporous geometry, anodization profile, and optical properties, 213f for optical sensing, 214f NAA-linear variable bandpass filters (NAALVBPFs), 206 207 NAA-optical microcavities (NAA-optical μCVs), 206 207, 216 218 characteristic nanoporous geometry, anodization profile, and optical properties, 216f sensing systems using, 217f NAA-PCs. See Nanoporous anodic alumina photonic crystals (NAA-PCs) NADESs. See Natural deep eutectic solvents (NADESs) NADH. See β-nicotinamide adenine dinucleotide (NADH) Nafion-gold nanoparticles-MXene (Au-NPMXene), 363 365 Nano-carbon allotropes, 380 Nano-MIP particles, 52 Nano-SUPRAS, 50 Nanobiosensors, 297 Nanocatalytic precipitation process, 281 282 Nanoceria, 352 Nanochip liquid chromatography, 36 Nanocomposite of CNTs, 309 310 strain sensor, 368 369 Nanodiamonds (NDs), 104, 379 380

522

Nanofibers as sorbent in microextraction techniques, 51 Nanofibrillated mesoporous carbon SPME fiber, 51 Nanofiltration (NF), 109 127, 159 Nanoheaters, 247 252 Nanomanometry, 258 262 Nanomaterial integrated analytical techniques, 276 Nanomaterial-based sensors carbon-based materials, 339 342 CNTs, 335 339 graphene, 331 335 nano/micromotors, 352 354 number of publications reported in Scopus, 330f Nanomaterial-based signal amplification, 318 Nanomaterial-integrated electrochemical analytical techniques, 288, 289t Nanomaterials (NMs), 3, 29, 44 45, 99 100, 159, 185, 275, 329, 376 377, 378f, 437, 473 in analytical procedures, 34f application in microextraction methods, 46 52 in sample preparation, 58 66 carbon-based, 45 characteristics, 475 476 economics, 441 442 and environment, 437 441 functionalization of, 395 intimate structure analysis, 483 legalization of nanotechnology, 441 442 magnetic NPs, 45 metallic/metallic oxide nanoparticles, 44 modern policy, 441 442 physical attributes analysis, 481 486 attributes vs. measurands, 479f standardization of methods for analysis, 477 480 polymer nanoparticles, 45 porosity and crystallinity, evaluating, 483 properties, functionality, and activity, 473 474 in separation techniques, 101 136 shape, evaluating, 482 483 silicon oxide nanoparticles, 44 size, analyzing, 480 481

Index

thorough analysis of nanomaterial surface attributes, 484 486 as tools and analytes, 32 36 zeta potential, analyzing, 481 Nanomedicine Characterization Laboratory (NCL), 477 479 Nanomedicines, 475 476, 484 486 safety of, 481 482 Nanometric analytical systems, 36 Nanometrology, 477 479 Nanomotors, 329 331, 352 354 Nanoparticle tracking analysis (NTA), 480 Nanoparticle-based membranes, 167 169 Nanoparticles (NPs), 34 35, 44, 75 76, 100, 276, 299, 329 331, 377, 415, 435 436, 440 Nanopolymers, 45 Nanopores of NAA, 205 Nanoporous anodic alumina (NAA), 203 207 fabrication, 203 205, 204f structural engineering, 205 207 Nanoporous anodic alumina photonic crystals (NAA-PCs), 202 203 architectures, 206 207 characteristics and optical properties, 208t as optical sensing platforms, 207 219 Nanoporous PCs, 201 202 Nanoscale characterization of CA, 451 Nanoscale graphitic carbon nitride/copper oxide hybrid material (Nano-g-C3N4/ CuO), 399 Nanoscience, 32 36, 139 classical components, 36f Nanoscopic imaging methods, 31 Nanoshells (NSs), 345 Nanosorbent, 51 Nanostructured (bio)sensors, 329 331 Nanostructured materials, 275 Nanostructured MIPs, 316 Nanotechnology, 33 36, 43, 100 101, 376 classical components, 36f history of, 32 Nanothermometers (NTMs), 227 based on band shift, 244 245 based on bandwidth, 246 dual and multicenter, 243 244 lifetimeNanothermometry, 234 252

Index

single-band intensity and double-band ratio, 236 243 National Environmental Policy Law, 441 National Institute of Health (NIH-NCL), 477 479 National Institute of Standard and Technology (NIST), 477 479 National Policy on Solid Waste, 441 Natural (re)sources, 4 Natural deep eutectic solvents (NADESs), 394 Natural products, 3 4 NBI-DTC. See Nitro benzylindoledithiocarbamate (NBI-DTC) NCL. See Nanomedicine Characterization Laboratory (NCL) Nd31, 236 237 NDs. See Nanodiamonds (NDs) Near-infrared (NIR) light, 21 22, 228 Near-infrared (NIR) irradiation, 227 Nernst equation, 30 31 Neutron scattering methods, 483 NF. See Nanofiltration (NF) NHS. See N-Hydroxysuccinimide (NHS) Ni-NPs supported on functionalized MWCNT (Ni@f-MWCNT), 309 310 Nickel oxide, 304 305 Nickel sulfide nanomaterial loaded on activated carbon (NiS-NP-AC), 48 Nickel:zinc sulfide, 51 NIH-NCL. See National Institute of Health (NIH-NCL) NIR. See Near-infrared (NIR) NiS-NP-AC. See Nickel sulfide nanomaterial loaded on activated carbon (NiS-NP-AC) NIST. See National Institute of Standard and Technology (NIST) Nitrate analysis, 193 Nitrite ion analysis, 193 Nitro benzylindoledithiocarbamate (NBIDTC), 424 425 Nitrogen oxide, 367 368 Nitrogen-doped GQDs (N-GQDs), 496 497, 499 500 Nitrophenols, 18 NMs. See Nanomaterials (NMs) Noble metallic nanoparticles, 44, 284, 299 304, 317 electrochemical sensors, 299

523

gold nanoparticles, 299 301 palladium nanoparticles, 303 304 platinum nanoparticles, 302 silver nanoparticles, 301 Non-carbonaceous nanomaterials, 342 352 electrochemical (bio)sensors, 343 348 optical (bio)sensors, 348 352 Noncovalent functionalization of carbonbased nanomaterials, 389 395 Noncovalent interactions, 417 420 Nondoped carbon nanodots, 9 Nonenzymatic H2O2 sensor, 301 “Nonlanthanide” nanomaterials, 234 235 Nonspherical irregular shapes, 107 NP-based membranes, 127 129 NPs. See Nanoparticles (NPs) NSs. See Nanoshells (NSs) NTA. See Nanoparticle tracking analysis (NTA) NTMs. See Nanothermometers (NTMs) Nuclear Accident Law, 441 Nucleic acid separation, 137 138 Numeral electrochemical biosensing approaches, 298 O Oasis-HLB, 79 OC. See Organic carbon (OC) Ochratoxin A (OTA), 347 OCPs. See Organochlorine pesticides (OCPs) Octahedral Au NPs (Oct Au NPs), 284 285 “Off On” CND-based PL systems, 17 20 Omix, 79 One-dimension (1D) graphitic materials, 339 nanomaterials, 32 33 nanostructures, 101 Optical (bio)sensing systems, 333 334 carbon nanotube-based (bio)sensors, 336 339 graphene-based biosensors, 333 335 microscopes, 31 nanosensors of pressure, 258 262 sensing mechanisms, 336 sensors, 201, 256 258 Optical biosensors carbon-based materials in, 340 342 non-carbonaceous nanomaterials

524

Optical biosensors (Continued) AgNPs, 349 350 AuNPs, 348 349 CuNPs and PtNPs, 350 351 inorganic nanoparticles, 352 Organic dendrimer-modified magnetic Fe3O4 nanoparticles, 88 dyes, 18 19 molecules, 16 19 analytical systems for food components, 16 17 probes for analytes of environmental importance, 17 19 probing analytes of biological importance, 19 probing principle of organophosphorus pesticides, 18f nanomaterials, 45 NPs, 377 polymer based nanomaterials, 105 Organic carbon (OC), 449 450 Organochlorine pesticides (OCPs), 382 Organophosphorous pesticides, 348 OTA. See Ochratoxin A (OTA) Oxidase enzymes, 347 Oxidation, 78, 381 Oxidized MWCNTs, 387 Oxidized poly(pyrrole), 127 129 Oxygen, 361 362 P p-naphtholbenzein (PNB), 65 p-nitroaniline dithiocarbamate (p-NA-DTC), 424 425 Packed IT-SPME technique, 46 48 PAH. See Poly(allylamine hydrochloride) (PAH) PAHs. See Polycyclic aromatic hydrocarbons (PAHs) Palladium (Pd), 106, 299 Palladium nanoparticles (Pd NPs), 303 304 PAMAM. See Poly(amidoamine) (PAMAM) PAMAM G4. See Poly(amidoamine) dendrimers (PAMAM G4) PAN. See 1-(2-Pyridylazo)-2-naphtol (PAN) PANI. See Polyaniline (PANI) “Paper Blue”, 347 Paper-based biosensor, 347

Index

Paper-based high-performance potentiometric sensor, 302 Paper-based multiassay, 350 Paper-based μTAS platforms, 187 Paracetamol, 316 317 Particle tracking analysis (PTA), 477 479 Particulate matter (PM). See Atmospheric aerosol Passive nanostructures, 33 PBNPs, 347 PBS. See Phosphate-buffered saline (PBS) PCR. See Polymerase chain reaction (PCR) PCs. See Photonic crystals (PCs) pDA. See Polydopamine (pDA) pDA/MWCNTs/polyvinylidene fluoride membrane, 171 PDDA. See Polydiallyldimethylammonium chloride (PDDA) PDMS. See Polydimethylsiloxane (PDMS) PDMS-OH. See Hydroxyl-terminated PDMS (PDMS-OH) PEDOT. See Poly(3,4ethylenedioxythiophene) (PEDOT) PEEK. See Poly(ether ether ketone) (PEEK) Pendimethalin, 424 425 PEO. See Poly(ethylene oxide) (PEO) Peptide nuclei acids (PNA), 335 Person-related factors, 31 Pesticides, 424 425 colorimetric recognition of, 416 420 PF. See Polysilicone fullerene (PF) pH-sensitive behavior, 13 Pharmaceuticals, 18 19 Phenthoate, 424 Phosphate-buffered saline (PBS), 425 Phospholipid-coated colloidal MNPs, 138 Phosphonium-based ionic liquids, 83 84 Photolithography, 186 187 Photoluminescence (PL), 201, 501 502 stability, 12 13 Photoluminescent CNDs (PL CNDs), 3 Photonic crystals (PCs), 201 202 Photonic stopband (PSB), 205, 218 219 Physical adsorption, 132 Physical interaction-based immobilization methods, 397 Pipette-tip SPE (PT-SPE), 393 PL. See Photoluminescence (PL)

Index

Plasma S-nitrosothiol derivatives (RSNOs), 299 Platinum (Pt), 299, 351 Pt-based functional nanocomposites, 302 Platinum nanoparticles (PtNPs), 302, 346 347 non-carbonaceous nanomaterials electrochemical (bio)sensors, 346 347 non-carbonaceous nanomaterials optical (bio)sensors, 350 351 Pleurotus eryngii, 395 PMMA. See Polymethyl methacrylate (PMMA) PNA. See Peptide nuclei acids (PNA) PNB. See p-naphtholbenzein (PNB) Point-of-care (POC) testing, 185, 276 Poly-(methyl methacrylate) discs, 189 Poly(2,6-diaminopyridine)-modified GO composite, 392 Poly(2,6-dimethyl-1,4-phenylene oxide), 167 Poly(3,4-ethylenedioxythiophene) (PEDOT), 306 Poly(allylamine hydrochloride) (PAH), 136 137 Poly(amidoamine) (PAMAM), 281 282 Poly(amidoamine) dendrimers (PAMAM G4), 284 285 Poly(ether ether ketone) (PEEK), 65 Poly(ethylene glycol)-grafted silica nanoparticles, 168 Poly(ethylene oxide) (PEO), 105 Poly(o-phenylenediamine)/Ag-NPs (PoPD/Ag-NPs), 314 316 Poly[(3-mercaptopropyl)-methylsiloxane], 186 187 Polyacrylonitrile extraction, 63 65 Polyacrylonitrile nanofibers, 161 Polyaniline (PANI), 314 316, 389 Polyclonal anti-AFB1 antibody, 279 280 Polycyclic aromatic hydrocarbons (PAHs), 84, 129 130, 384 Polydiallyldimethylammonium chloride (PDDA), 427 429 Polydimethylsiloxane (PDMS), 45, 58, 187 Polydispersity, 107, 480 481 Polydopamine (pDA), 167 168 pDA-coated magnetic Fe3O4 nanoparticles, 89 Polyethersulfone hollow fiber ultrafiltration membrane, 161

525

Polyhedral oligomeric silsesquioxane NPs, 105 Polylysine-coated diamond NMs, 383 Polymer nanomaterials, 313 317. See also Carbon nanomaterials conducting polymers, 314 316 dendrimers, 313 314 molecularly imprinted polymers, 316 317 Polymer nanoparticles, 45 inorganic and mixed polymers, 45 organic nanomaterials, 45 selective nanomaterials, 45 Polymerase chain reaction (PCR), 186 Polymeric/polymers, 187, 389, 400 fullerene, 385 IL sorbents, 399 materials, 127 nanocomposites, 387 nanomaterials, 317 NPs, 377 polymer-based porous membranes, 160 polymer-based sensors, 313 polymerization-based fabrication, 186 187 polymerization-based prototyping, 186 187 Polymethyl methacrylate (PMMA), 187 Polypropylene amine dendrimers (POPAM), 387 Polypyrrole (PPy), 281 282, 313 316 Polysilicone fullerene (PF), 385 Polystyerene (PS), 165 Polystyrene latex NPs, 105 Polysulfone (PSF), 105 106, 127 129 Polythiophene, 314 316 Polyvinyl alcohol (PVA), 105 POPAM. See Polypropylene amine dendrimers (POPAM) PoPD/Ag-NPs. See Poly(ophenylenediamine)/Ag-NPs (PoPD/AgNPs) Porosity of nanomaterials, 483 Porous silicon (pSi), 202 203 Potentiostatic anodization, 398 399 PP. See Protein precipitation (PP) PPa. See Pyrrolepropylic acid (PPa) PPy. See Polypyrrole (PPy) Pr31, 236 Precision, 31 Preconcentration, 34 35

526

Pressure chamber, 253 determination, 256 258 pressure-driven flow, 188 pressure-sensitive adhesive films, 189 pressure-transmitting medium, 253 254 Primary thermometers, 234 Pristine MWCNTs, 385 386 Probing analytes of biological importance, 19 of environmental importance, 17 19 Profenofos, 424 Propanal, 367 368 Propazine-imprinted thin layer, 82 Protein biosensor, 317 318 and peptide separation, 138 Protein precipitation (PP), 57 58 Prothioconazole, 417 420 Prunus avium, 6 7 Prussian Blue, 347, 352 PS. See Polystyerene (PS) PSB. See Photonic stopband (PSB) Pseudomonas aeruginosa, 395 PSF. See Polysulfone (PSF) pSi. See Porous silicon (pSi) PT-SPE. See Pipette-tip SPE (PT-SPE) PTA. See Particle tracking analysis (PTA) PtNPs. See Platinum nanoparticles (PtNPs) Pulse-like anodization approaches, 205 206 PVA. See Polyvinyl alcohol (PVA) 1-(2-Pyridylazo)-2-naphtol (PAN), 385 386 Pyrolysis, 7 8 Pyrrolepropylic acid (PPa), 281 282 Q QDs. See Quantum dots (QDs) Quality control analysis, 473 475, 484 486 Quantum dots (QDs), 282 284, 329 331. See also Carbon nanodots (CNDs) Quantum yield (QY), 230 Quenching, 336 of emitted fluorescence signal, 13 Quinalphos, 424 425 R Rabbit anti-mouse IgG alkaline phosphatase (RaMIgG-ALP), 280

Index

Ractopamine-dithiocarbamate (RAC-DTC), 424 425 RAC-DTC-Au NPs, 425 Radiative forcing, 449, 450f Raman scattering, 336 Raman spectrometers, 255 256 Raman spectroscopy, 460 461, 462f RaMIgG-ALP. See Rabbit anti-mouse IgG alkaline phosphatase (RaMIgGALP) Rapid Fourier transformation cyclic voltammetry, 280 Reduced graphene oxide (rGO), 45, 50 51, 162, 280 281, 301, 332, 393 Reflectometric interference spectroscopy (RIfS), 201, 209 211 Relative sensitivity, 232 233 Relative standard deviation (RSD), 382, 422 427 Reliability, 31 Remote, contactless temperature sensing, 231 234 Renaissance, 329 Representability, 31 Reverse osmosis (RO), 127 membranes, 159 Reverse-phase LC (RPLC), 99 100 rGO. See Reduced graphene oxide (rGO) Rhodamine 6 G, 365 367 RIfS. See Reflectometric interference spectroscopy (RIfS) RNA nanotechnology, 331 RO. See Reverse osmosis (RO) Robustness, 31 Royal Academy of Engineering, 441 RPLC. See Reverse-phase LC (RPLC) RSD. See Relative standard deviation (RSD) RSNOs. See Plasma S-nitrosothiol derivatives (RSNOs) Rutile TiO2 mesocrystals, 287 288 S Safety risk of nanomaterials, 437 Salmonella enterica serovar Typhi, 193 194 Salmonella enteritidis, 194 Salmonella typhimurium, 345 SAM. See Self-assembled monolayers (SAM)

Index

Samarium oxide nanorods (n-Sm2O3 nanorods), 287 288 Sample preparation, 43, 57 58 nanomaterials application in, 58 66 SBSE. See Stir bar sorptive extraction (SBSE) Scanning electron microscopy (SEM), 161, 384, 387 388, 455 457, 457f, 477 479 with EDX, 455 458 Scanning transmission electron microscopy (STEM), 455 457 Sceptical Chymist, The (Boyle), 30 31 Scientific Committee on Consumer Products, 435 SCMNPs. See γmercaptopropyltrimethoxysilane-modified silica-coated magnetic NPs (SCMNPs) Screen-printed electrodes (SPEs), 332 Secondary electron (SE), 455 457 Secondary thermometers, 234 Selective nanomaterials, 45 Selectivity, 31 Self-assembled monolayers (SAM), 284 285 SEM. See Scanning electron microscopy (SEM) Sensing, 329 Sensitive electrochemical paracetamol sensor, 316 317 Sensitivity, 31 Separation techniques, nanomaterials in, 101 136, 109f, 110t capillary electrophoresis, 131 132 carbon nanostructures, 101 104 chromatography, 133 135 inorganic silica nanoparticles, 105 106 magnetic NPs, 107 108 membrane-based separation, 108 129 metal organic frameworks, 107 metal oxide nanoparticles, 106 107 metallic nanoparticles, 106 microfluidics, 136 nanoparticles in, 103t organic polymer based nanomaterials, 105 potential applications of nanomaterialbased separation techniques, 136 139 application in material science, 138 139

527

application in metabolite separation, 138 isolation of specific target cells from population, 136 137 nucleic acid separation, 137 138 protein and peptide separation, 138 solid-phase extraction technique, 129 131 SERS method. See Surface-enhanced Raman spectroscopic method (SERS method) SG/PPy SPME coating. See Sulfonated graphene/polypyrrole SPME coating (SG/ PPy SPME coating) Shape of nanomaterials, 482 483 Shigella sonnei, 193 194 Shortpass filters, 206 207 Silane groups, 383, 396 Silanization, 396 Silica-coated magnetic cobalt nanoparticles, 83 84 Silica-coated MNP, 130 Silica nanoparticles, 127 129, 134, 138 Silicon, 187 Silicon dioxide, 127 129 Silicon oxide NPs, 44, 46 48 Silicone rubber, 45 Silver (Ag), 106, 287 288, 299 Ag-impregnated filter, 346 Silver bromide (AgBr) nanocomposites polymer-based membrane, 127 129 Silver nanoclusters (AgNCs), 349 350 Silver nanoparticles (AgNP), 106, 301, 415, 420 non-carbonaceous nanomaterials electrochemical (bio)sensors, 345 346 non-carbonaceous nanomaterials optical (bio)sensors, 349 350 Simple alkoxide-based sol gel method, 50 51 Single Particle Soot Photometer (SP2), 465 Single-band intensity nanothermometers, 236 243 Single-stranded DNA (ss DNA), 332 333 Single-walled carbon nanohorn (SWNH), 276 279, 306 308 Single-walled carbon nanotubes (SWCNTs), 45, 59, 104, 276 279, 306 308, 335, 379 SWCNTs-based columns, 134 135

528

Sinusoidal pulse anodization (SPA), 206 207 Size of nanomaterials, 480 481 Sm21-doped SrB4O7 compound, 258 Sm31, 238 Smartphone-based μTAS, 189 193 Sodium montmorillonites (Na-Mont), 288 Soft lithography, 186 187 Sol gel chemistry deposition, 207 209 coating, 382 method, 50 51, 396 synthesis, 77 78 Solid-phase extraction (SPE), 45, 57 63, 76, 79, 104, 129 131, 377, 381 conventional solid-phase extraction, 129 dispersive solid-phase extraction, 130 novel nanomaterials applied in, 60t, 64t solid-phase microextraction, 130 131 SPE-FAAS procedure, 390 SPE-UHPLC MS/MS procedure, 398 399 Solid-phase microextraction (SPME), 46, 57 58, 63 65, 107 108, 377, 399 401 Solvothermal carbonization, 4 7 synthesis, 397 Sorbents, 46 sorbent-used MSPE, 400 Sorption-based sample preparation methods, 380 Sorptive extraction methods, 46 Sorptive-based extraction procedures, 392 sp2-hybridization, 102 SP2. See Single Particle Soot Photometer (SP2) SPA. See Sinusoidal pulse anodization (SPA) SPE. See Solid-phase extraction (SPE) Spectroscopy techniques for CA, 460 465 Speed, 31 SPEs. See Screen-printed electrodes (SPEs) SPME. See Solid-phase microextraction (SPME) SPR. See Surface plasmon resonance (SPR) Spray approach, 79 Square-wave voltammetry, 346 SrB2O4:Sm21 nanocrystals, 259 ss DNA. See Single-stranded DNA (ss DNA)

Index

Standardization of methods for analysis, 477 480 Staphylococcal enterotoxin B, 194 195 Staphylococcus aureus, 167 168, 193 194, 345 346 Static quenching, 20 STEM. See Scanning transmission electron microscopy (STEM) Stepwise pulse anodization (STPA), 206 207 Sterigmatocystin, 276 279 Stir bar sorptive extraction (SBSE), 46, 51, 57 58, 65 Stoichiometric concepts, 30 31 STPA. See Stepwise pulse anodization (STPA) Structure analysis of nanomaterial, 483 Sub-Stark TCLs, 243 Sucrose-Ag NPs, 420 Sucrose-functionalized Ag NPs, 420 Sudan I, 194 Sulfonated graphene/polypyrrole SPME coating (SG/PPy SPME coating), 391 Sulfur dioxide, 367 368 Sunset yellow, 16 17 Supramolecular solvent microextraction (SUPRAS microextraction), 50 Surface attributes of nanomaterial, 484 486 Surface chemistry, 219, 424 425, 449, 463 464 of NAA-PCs, 207 209 Surface plasmon resonance (SPR), 415 416 spectroscopy, 201 SPR-based biosensor, 424 Surface plasmons, 415 Surface-enhanced Raman spectroscopic method (SERS method), 365 367 Surface-modified Ag nanoparticles, 416 420, 418f functional Ag nanoparticles, 421t Surface-modified Au nanoparticles, 420 429 functional Au nanoparticles, 428t SWCNTs. See Single-walled carbon nanotubes (SWCNTs) SWNH. See Single-walled carbon nanohorn (SWNH) Syringe membrane, 108 127

Index

T T7 bacteriophage, 194 TAR. See 4-(2-Thiazolylazo)resorcinol (TAR) Tartrazine, 16 17 Tb31, 243 Tcd B. See Clostridium difficile toxin B (Tcd B) TCh. See Thiocholine (TCh) TCLs. See Thermally coupled levels (TCLs) Telechelic poly(N-isopropylacrylamide) polymer chains, 136 TEM. See Transmission electron microscopy (TEM) Temperature measurements, 229 230 temperature-induced broadening of emission lines, 246 uncertainty, 233 TEOS. See Tetramethylorthosilicate (TEOS) TEP. See Tri-ethyl phosphate (TEP) Terahertz (THz), 370 MXene for Terahertz sensing, 370 Terbufos, 424 425 5,10,15,20-tetrakis[4-carboxyl phenyl]porphyrin (H2TCPP), 352 Tetramethylorthosilicate (TEOS), 46 48 TEOS-MTEOS-SiO2 NPs, 46 48 TGA. See Thioglycolic acid (TGA) Thermal decomposition technique, 76 77 Thermalization process, 231 232 Thermally coupled levels (TCLs), 228 229 Thermocouples, 227, 229 230 Thermometric parameter, 231 232 Thermosensitive GO-based ion-imprinted nanocomposite membranes, 171 172 Thiacloprid, 424 425 1-(2-Thiazolylazo)-2-naphthol, 385 4-(2-Thiazolylazo)resorcinol (TAR), 385 Thin film-based membranes, 160 Thiocholine (TCh), 352, 417 420 Thioglycolic acid (TGA), 417 420 Thiolene click chemistry, 393 Three-dimensional MAX phases (3D MAX phases), 361 Three-dimensional nanosystems, 33 Three-dimensional porous graphene (3D GN), 312 313

529

3D IL-ferrite functionalized GO nanocomposite (3D-ILFe3O4-GO), 393 3D IL-functionalized magnetic GO nanocomposite (3D-IL@mGO), 393 3D printing, 186 187 Ti3C2-MQDs, 365 Ti3C2-tyrosinase biosensor, 365 367 Ti3C2OH2 MXene, 367 368 Time-of-flight secondary ion mass spectroscopy (ToF-SIMS), 464 Time-off-light (TOF), 383 Tin oxide, 304 305 Titanium, 106 107 Titanium dioxide, 435 436 photocatalyst, 438 Titanium oxide, 304 305, 363 365 NPs, 134, 172 Tm31, 241 243 TMSPDETA. See N1-(3Trimethoxysilylpropyl) diethylenetriamine (TMSPDETA) TMSPEDA. See N-(3Trimethoxysilylpropyl) ethylenediamine (TMSPEDA) TOF. See Time-off-light (TOF) ToF-SIMS. See Time-of-flight secondary ion mass spectroscopy (ToF-SIMS) Top-down approaches, 4 Toxicity of nanoparticles, 437 438 research of GQD materials, 500 501 Traditional membranes, 159 160 Transdermal route, 439 Transition metals, 346, 361 Transmission electron microscopy (TEM), 31, 387 388, 420, 455 457, 457f, 482 483 with EDX, 458 459 Tri-ethyl phosphate (TEP), 50 51 Triazophos, 417 420 Trichromatic lateral flow immune assay, 350 1,3,5-Triformylbenzene (Tb), 87 88 Trimethoxymethylsilane (MTEOS), 46 48 N1-(3-Trimethoxysilylpropyl) diethylenetriamine (TMSPDETA), 383 N-(Trimethoxysilylpropyl) ethylenediamine triacetic acid (EDTA-silane), 386 N-(3-Trimethoxysilylpropyl) ethylenediamine (TMSPEDA), 383

530

Trimethylolpropane trimethacrylate, 82 1,1,1-Tris(hydroxymethyl) propane trimethacrylate, 105 TRPS. See Tunable resistive pulse sensing (TRPS) Tunable resistive pulse sensing (TRPS), 477 480 Two-dimension (2D) graphitic materials, 339 layered materials, 361 MXene, 362 363 nanostructures, 101 NP-membranes, 127 129 Tyrosinase, 336 L-Tyrosine functionalized CNTs, 130 131 U UA. See Uric acid (UA) UAME-NMSPD. See Ultrasound-assisted microextraction-nanomaterial solid-phase dispersion (UAME-NMSPD) UC. See Upconversion (UC) UF. See Ultrafiltration (UF) Ultra-high pressure liquid chromatographyelectrospray ionization-tandem mass spectrometry (UPLCMS/MS), 63 65 Ultrafast electrochemiluminescent immunoassay, 282 284 Ultrafiltration (UF), 109 Ultrasound-assisted microextractionnanomaterial solid-phase dispersion (UAME-NMSPD), 48, 49f Ultraviolet (UV), 227 absorption, 9 10 Ultraviolet visible spectrometry (UV Vis spectrometry), 11f, 416 420 United Kingdom Royal Society, 441 Upconversion (UC), 12, 227 luminescence, 235 NPs, 228 QY, 230 UPLCMS/MS. See Ultra-high pressure liquid chromatography-electrospray ionizationtandem mass spectrometry (UPLCMS/ MS) Uric acid (UA), 299 301, 363 365 US Environmental Protection Agency (USEPA), 440

Index

UV. See Ultraviolet (UV) UV Vis spectrometry. See Ultraviolet visible spectrometry (UV Vis spectrometry) V van der Waals forces, 397 Vibrio parahemolyticus, 193 194 Vinylimidazole, 82 Voltammetric technique, 304 W Weak anion exchange (WAX), 58 Weak cation exchange (WCX), 58 Weaker physical interactions, 397 Wearable electrochemical sensor, 310 311 X X-ray photoelectron spectroscopy (XPS), 384, 463 464, 484 486 X-rays, 455 457, 483 Xerogels, 45 Y Yb31, 243 excitation, 235 Yo-yo experiments, 233 Yttrium nanoparticle-based polysulfone membrane, 167 Z Zearalenone, 288 Zeolite, 127 129 Zero dimension (0D) nanomaterials, 32 33 nanostructures, 101 Zeta potential, 474 475, 477 479, 481 Zetasizer Nano ZSP, 384 Zinc, 106 107 Zinc oxide, 304 305 Zincon-immobilized silica-coated magnetic Fe3O4 NPs, 401 402 Zirconia NPs, 106 107, 134 Zirconium, 50, 106 107 Zirconium oxide, 127 129 Zwitterion-functionalized polymer microspheres, 59 63