ALBERTO ESCARPA Analytical Chemistry, Physical Chemistry and Chemical Engineering Department, University of Alcala, SpainMARÍA CRISTINA GONZÁLEZ Analytical Chemistry, Physical Chemistry and Chemical Engineering Department, University of Alcala, SpainMIGUEL ÁNGEL LÓPEZ Analytical Chemistry, Physical Chemistry and Chemical Engineering Department, University of Alcala, Spain

"This book can surely provide an excellent overview of the current state of art of electrochemical applications in the ambit of food and beverage analyses. In addition, this work is a valuable resource for scientists studying the evolution of instruments and the consequent introduction of new concepts and improved systems." (Analytical and Bioanalytical Chemistry, 2016)

• List of Contributors xvPreface xix1. Electroanalysis and Food Analysis 1Paloma Yá˜nez-Sede˜no and José M. Pingarrón1.1 Introduction and Adequacy of Electroanalysis for Food Analysis 11.2 Methodologies Related to Measurement Techniques 21.2.1 Continuous Detection Methods 21.2.2 Stripping Analysis 51.2.3 Potentiometry and Chronopotentiometry 71.2.4 Electronic Tongues 71.2.5 Impedance Spectroscopy 91.3 Electrochemical Sensors and Biosensors for Food Components 91.3.1 Molecularly Imprinted Electrodes 91.3.2 Enzyme Biosensors 101.3.3 Affinity Biosensors 121.4 Nanomaterials for Electrochemical Analysis of Food 141.5 Future Trends 16Acknowledgments 16References 16Part I Electroanalytical Techniques in Batch and Continuous Systems in Food Analysis 212. Voltammetric Techniques 23Sandra Mendoza, Erika Bustos, Juan Manr´ýquez and Luis A. God´ýnez2.1 Introduction 232.2 An Overview of Sweep Potential Electrochemical Techniques 232.2.1 Linear Sweep Voltammetry/Cyclic Voltammetry 252.2.2 Pulse Voltammetry Techniques 272.2.3 Normal Pulse Voltammetry 272.2.4 Differential Pulse Voltammetry 282.2.5 Square Wave Voltammetry 282.2.6 Stripping Voltammetry 292.3 Applications of Voltammetric Techniques in Food Analysis 312.3.1 Food Contaminants: Heavy Metals, Pesticides, and Toxic Substances 312.3.2 Trace Essential Elements 352.3.3 Food Additives 352.3.4 Nutraceuticals: Phenolic Acids, Flavonoids, and Others 402.4 Concluding Remarks 44Abbreviations 44References 443. Flow-Injection Analysis with Electrochemical Detection 49Fabiana Silva Felix and Lúcio Angnes3.1 Introduction 493.2 Screening the Literature 513.3 Voltammetry under Flowing Stream 523.4 Flow Injection Analysis Principles 523.4.1 Liquid Propulsion in FIA 543.4.2 Methods of Sample Introduction in an FIA System 563.4.3 Flow Cell Designs 573.5 Batch Injection Analysis Principles 583.6 Sequential Injection Analysis Principles 603.7 Applications 613.7.1 FIA and Voltammetric Detection–A Happy Marriage 613.7.2 BIA with Voltammetric Detection 643.7.3 SIA with Voltammetric Detection 653.8 Advantages of Voltammetry under Flowing Stream 663.9 Concluding Remarks 67Acknowledgments 67References 674. HPLC Techniques with Electrochemical Detection 73Manuel Chicharro Santamar´ýa, Mónica Moreno Barambio and Alberto Sánchez Arribas4.1 Introduction 734.2 Fundamentals 754.2.1 Electrochemical Cell 754.2.1.1 Electrode Materials 764.2.1.2 Flow-Cell Designs 774.2.1.3 Operation Modes 804.2.2 Development of HPLC-ED Methods 854.2.2.1 Getting Started 864.2.2.2 Hydrodynamic Voltammograms 864.2.2.3 Mobile Phase Composition 874.2.2.4 Temperature 894.2.2.5 Flow Rate 904.2.2.6 Electrode Treatment 904.2.2.7 Gradient Elution 914.2.2.8 Maintenance of HPLC-ED Systems 914.3 Analytical Designs and Performance 924.3.1 Natural Constituents 924.3.1.1 Carbohydrates 924.3.1.2 Amino Acids 944.3.1.3 Vitamins 964.3.1.4 Natural Phenolic Compounds 974.3.2 Nonanthropogenic Contaminants 984.3.2.1 Biogenic Amines 984.3.2.2 Mycotoxins 1004.3.3 Anthropogenic Contaminants 1014.3.3.1 Antibiotics 1014.3.3.2 Pesticides (Herbicides, Insecticides, and Fungicides) 1024.4 Concluding Remarks 104References 1055. Capillary Electrophoresis with Electrochemical Detection 117Gang Chen5.1 Introduction 1175.2 Separation Techniques in Agricultural and Food Analysis 1185.3 ECD in the CE Analysis of Foods and Agricultural Products 1195.3.1 Amperometric Detection 1195.3.2 Conductivity Detection and Potentiometric Detection 1205.4 Instrumentations of CE-ECD 1215.5 Determination of Nutritions by CE-ECD 1225.5.1 Amino Acids and Peptides 1225.5.2 Carbohydrates 1245.5.3 Vitamins 1265.5.4 Ions 1275.6 Determination of Phenolic Compounds by CE-ECD 1275.6.1 Phenols in Tea 1275.6.2 Phenols in Coffee 1275.6.3 Phenols in Wines 1275.6.4 Phenols in Herbal Drugs 1285.6.5 Flavones in Herbal Drugs 1285.7 Determination of Purines by CE-ECD 1305.8 Determination of Food Additives by CE-ECD 1305.8.1 Preservatives 1305.8.2 Antioxidants 1315.8.3 Colors 1315.8.4 Artificial Sweeteners 1315.9 Summary 131Abbreviations 132Acknowledgments 132References 133Part II Electrochemical Sensing in Food Analysis 1376. Microelectrode Designs 139Jonathan P. Metters and Craig E. Banks6.1 Introduction 1396.2 Microfabrication Techniques 1426.2.1 Lithography and Related Processes (Deposition, Sputtering, Other Relevant Technologies) 1426.3 Screen-Printing for Producing Electrochemical Sensors 1496.3.1 Improving Mass Transport 1516.3.2 Metal Oxide Electrodes, Metal and Nano and Micro Modified Screen-Printed Sensors 1596.4 Conclusions and Perspectives 161References 1617. Potentiometric Sensors 169Geza Nagy and L´ývia Nagy7.1 Introduction 1697.2 The Types of Potentiometry 1697.2.1 Potentiometric Stripping Analysis 1707.2.2 Zero Current Potentiometry 1717.2.3 Direct Potentiometry 1757.2.4 Titrimetric Methods 1777.3 The Selectivity of Ion-selective Electrodes and Its Determination 1787.3.1 The Selectivity Coefficient 1787.3.2 Separate Solution and Mixed Solution Methods 1787.3.2.1 Separation Solution Methods 1797.3.2.2 Mixed Solution Methods 1807.4 Measuring Electrodes Used in Potentiometric Analysis 1817.4.1 Ion-selective Field Effect Transistors 1837.4.2 Severinghaus-type Probes 1837.4.3 Potentiometric Enzyme Electrodes 1847.5 Special Tasks 1857.5.1 pH Measurements 1857.5.2 Miscellaneous Analytical Tasks by Potentiometric Methods 1907.6 Application of Potentiometric Measurements for Anions 1917.6.1 Determination of Chloride Ion Concentration 1917.6.1.1 Measurement of Cl− Concentration in Milk 1927.6.1.2 Measurement of Cl− Concentration in Meat and Meat Products 1927.6.1.3 Measurement of Cl− Concentration in Butter 1927.6.1.4 Measurement of Cl− Concentration in Mayonnaise 1927.6.1.5 Measurement of Cl− Concentration in Soil Samples 1927.6.1.6 Chloride Ion Determination in Fruit Juice 1937.6.2 Determination of Fluoride Ion Concentration 1937.6.2.1 Fluoride Content of Wines 1947.6.3 Applications of EPA Methods for Anion and Cation Analysis 1947.6.4 Determination of Potassium Ion Concentration 1957.6.5 Determination of Nitrate Ion Concentration 1957.6.5.1 Nitrate Contain of Vegetables 1957.6.6 Determination of Calcium Ion Concentration 1977.6.7 Determination of Sweetening Additive Concentration 1977.6.8 Determination of Fumaric Acid Concentration 1977.6.8.1 Measuring the Fumarate Content in Gelatin 1977.6.9 Quantification of Food Preservatives 1987.6.9.1 Quantification of Sorbate 1987.6.9.2 Quantification of Benzoate 1987.6.10 Determination of Aluminum Ion Concentration 1997.6.11 Methods for Detecting Histamine 199References 2008. Electrochemical Enzyme Biosensors 207Ilaria Palchetti and Marco Mascini8.1 Introduction 2078.2 General Features of Enzyme Biosensors 2098.2.1 Enzyme Biosensor Assembly 2128.2.2 Enzyme Biosensor Stability 2138.2.3 Biosensors Based on the Principle of Enzyme Inhibition 2138.3 Analytical Features of Enzyme Based Biosensors 2148.3.1 Biosensor Calibration 2148.3.2 Biosensor Calibration for Determination of Inhibitors 2158.3.3 Practical Aspects 2158.3.3.1 Response Time 2158.3.3.2 Thickness of the Enzyme Layer 2168.3.3.3 Effect of Additional Membranes 2168.4 Examples of Electrochemical Enzymatic Biosensors for Food Analysis 2168.4.1 Detection of Pesticides 2178.5 Conclusion 219References 2209. Electrochemical Immunosensors 223M. Teresa Fernández-Abedul, M. Bego˜na González-Garc´ýa and Agust´ýn Costa-Garc´ýa9.1 Introduction 2239.2 Defining the Problem: The Targets 2259.3 Recognizing the Target 2319.3.1 Antibodies 2319.3.2 Antigens 2369.4 Immunosensing Architectures 2369.4.1 Components of the Sensing Layer 2389.4.2 Surface Engineering Procedures 2569.4.3 Renewable Solid Surfaces 2599.5 Performing Affinity Interactions for Molecular Recognition 2609.6 Transducing Immunological Events 2639.6.1 Electrode Materials and Types 2639.6.1.1 Film Electrodes 2649.6.2 Electrochemical Detection Methodologies 2669.6.2.1 Label-Free Approaches 2679.6.2.2 Amperometric Response to Labels 2709.7 Advancing in Real Immunosensing 2749.7.1 Multiplexed Determinations 2759.7.2 Automation of Immunosensors 2779.8 Processing Data 2789.9 Conclusions 278Abbreviations 280References 28310. Electrochemical Genosensors 295Briza Pérez-López and Arben Merkoçi10.1 General Introduction on Electrochemical Genosensors 29510.1.1 Operation Principles 29610.1.1.1 Label-Free (Direct) Detection 29610.1.1.2 Label-Based (Indirect) Detection 30010.2 Detection Methodologies 30210.2.1 Voltammetric/Stripping 30310.2.2 Potentiometric 30410.2.3 Impedimetric 30610.2.4 Conductometric 30610.3 Applications 30710.3.1 Species Identification 30710.3.2 Contaminant Monitoring 30910.4 Conclusions and Future Trends 311Acknowledgments 311References 31111. Electrochemical Biosensors Based on Nanomaterials 317Joseph Wang11.1 Why Nanoscale Materials? 31711.2 Nanowires, Nanotubes, and Nanoparticles 31711.3 Nanomaterial-based Electrochemical Biosensors 31911.3.1 Nanomaterial-based Biocatalytic Sensors 31911.3.2 Nanomaterial-based Bioaffinity Sensors 32111.4 Future Prospects 325References 32612. Electrochemical Sensing on Microfluidic Chips 331Alberto Escarpa, Mar´ýa Cristina González and Miguel A. López12.1 Electrochemical Detection Implementation in Microfluidic Chips 33112.2 Microchip Electrophoresis with Electrochemical Detection for Food Analysis 33512.2.1 Microchip Electrophoresis with Amperometric Detection for Organic Food Analytes 33512.2.2 Microchip Electrophoresis with Amperometric Detection for Inorganic Food Analytes 34112.2.3 Microchip Electrophoresis with Conductometric Detection for Food Analysis 34112.3 Microfluidic Chips with Nanomaterial-Based Electrochemical Detection for Food Analysis 34212.4 Microfluidic Electrochemical Biosensing Chips for Food Analysis 34612.5 Outlook 350Acknowledgments 351Acronyms 351References 35213. Nanoelectrochemistry Applications Based on Electrospinning 357Matteo Scampicchio, Maria Stella Cosio, Solomon Lemma Mengistu and Saverio Mannino13.1 A Note on Nanoelectrochemistry 35713.2 Electrochemical Sensors Modified with Nanofibrous Membranes 35813.3 Introduction to Electrospinning 35913.4 Applications of Electrochemical Sensors Based on Electrospinning 36113.4.1 Nanofibrous Membranes as Coating Material 36113.4.2 High Permeability 36213.4.3 Selective Barrier to Diffusion 36213.4.4 Conducting Nanofibrous Membranes 36413.4.5 Biosensor Based on Nanofibrous Membranes 369References 37414. Electrochemical Impedance Spectroscopy 381Araceli González-Cortés14.1 Introduction 38114.2 Impedance Spectroscopy–Theoretical Background 38214.3 Chemical Sensors 38714.4 Electrochemical Biosensors Based on Impedance Spectroscopy 39014.4.1 Enzymatic Biosensors 39114.4.2 Immunosensors 39214.4.2.1 Impedimetric Immunosensors Using Interdigitated Array Microelectrodes 40314.4.3 Genosensors and Aptasensors 40614.5 Nonelectrochemical Interfacial Impedance 41014.6 Conclusions and Perspectives 414References 415Part III Industrial Implications 42115. Electroanalysis in Food Process Control 423Maria Stella Cosio, Simona Benedetti, Matteo Scampicchio and Saverio Mannino15.1 Sensors in Food Process 42615.2 Electronic Nose 42915.3 Electronic Nose Technologies 43015.3.0.1 Metal Oxide Semiconductors 43115.3.0.2 Metal Oxide Semiconductor Field-Effect Transistors 43115.3.0.3 Conducting Organic Polymers 43115.3.0.4 Piezoelectric Crystal Sensors 43215.4 Electronic Noses for the Food Industry 43315.5 Electronic Tongue 43415.6 Pattern Recognition Models 43615.7 Sampling 43715.8 Conclusions 439References 43916. Instrumental Aspects of Food Analysis by Electrochemical Methods 443Wendell K. T. Coltro, Maria F. Mora and Carlos D. Garcia16.1 Introduction 44316.2 Principles 44416.3 Instrumentation for Electrochemical Detection 44516.3.1 Instruments for Voltammetric Techniques 44516.3.1.1 Amperometry 44516.3.1.2 Pulsed Amperometric Detection 44616.3.1.3 Voltammetry 44716.3.2 Instrumentation for Potentiometric Techniques 44816.3.3 Instruments for Conductometric Techniques 44916.3.4 Instruments Developed for Portability 45116.3.5 Low-Cost Potentiostats 45516.3.6 Remotely Controlled Instruments 45916.3.7 Electrochemical Detectors Coupled to Microchip Capillary Electrophoresis 46016.4 Conclusions 464Acknowledgments 464References 464Index 479