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CHEMICAL SENSORSAND BIOSENSORS

Brian R. EgginsUniversity of Ulster at Jordanstown

Northern Ireland, UK

JO H N W ILEY & SO NS , LTD

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Contents

Series Preface xv

Preface xvii

Acr onym s, Abb reviations and Sym bols xix

Abo ut the Author xxiii

1 Introduction 1

1.1 Introdu ction to Sensors 1

1.1.1 W hat are Sen sors? 1

1.1.2 The Nose as a Sensor 3

1.2 Sen sors and Bio sensors - Definitions 4

1.3 Aspects of Sen sors 5

1.3.1 Recogn ition Elem ents 5

1.3.2 Transducers - the Detector Device 5

1.3.3 M ethod s of Immobilization 6

1.3.4 Perfo rmance Fac tors 7

1.3.5 Areas of Application 7

2 Transduction Elem ents 11

2.1 Electroch em ical Transduce rs - Introduction 12

2.2 Potentiometry and Ion-Selective Electro des: The Ne rnst

Equation 12

2.2.1 Ce lls and Elec trodes 12

2.2.2 Reference Electrode s • 16

2.2.3 Quantitative Relationsh ips: Th e Nernst Equation 18

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viii Chemical Sensors and Biosensors

2.2.4 Practical Aspects of Ion-Selective Electrodes 23

2.2.5 M easurem ent and Calibration 24

2.3 Voltammetry and Am perometcy 27

2.3.1 Linea r-Sw eep Voltammetry 27

2.3.2 Cyclic Voltammetry 302.3.3 Chronoam perometry 32

2.3.4 Am perometry 34

2.3.5 Kinetic and Catalytic Effects 35

2.4 Conductivity 36

2.5 Field-Effect Transistors 38

2.5.1 Sem iconductors - Introduction 39

2.5.2 Se m icond uctor-S olution Contact 42

2.5.3 Field-Effect Transistor 432.6 Modified Electrode s, Thin-F ilm Electrodes and Screen-Printed

Electrodes 46

2.6.1 Thick -Film - Screen-Printed Electrodes 46

2.6.2 M icroelectrodes 47

2.6.3 Thin-F ilm Electrodes 49

2.7 Photom etric Sensors 50

2.7.1 Introdu ction 50

2.7.2 Op tical Techn iques 522.7.3 U ltraviolet and Visible Absorption Spectroscopy 53

2.7.4 Fluores cence Spectroscopy 53

2.7.5 Lum inescence 55

2.7.6 Optical Transd ucers 61

2.7.7 De vice Con struction 64

2.7.8 Solid-Phase Absorption Lab el Sensors 64

2.7.9 Applications 66

Further Rea ding 66

3 Sensing Elemen ts 69

3.1 Introduc tion 70

3.2 Ionic Rec ognition 70

3.2.1 Ion-Se lective Electrodes - Introduction 70

3.2.2 Interferences 70

3.2.3 Con ducting Devices 72

3.2.4 M odified Electrod es and Screen -Printed Electrodes 72

3.3 M olecular Reco gnition - Chem ical Rec ognition Ag ents 82

3.3.1 Therm odynam ic - Com plex Form ation 82

3.3.2 K ine tic-C ata lytic Effects: Kinetic Selectivity 84

3.3.3 M olecular Size 85

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Contents , ix

3.4 M olecular Reco gnition - Spectroscopic Recogn ition3.4.1 Introduction

3.4.2 Infrared Spectroscopy - Mo lecular

3.4.3 Ultraviolet Spectroscopy - Less Selective

3.4.4 Nu clear M agnetic Resona nce Spectroscopy - NeedsInterpretation

3.4.5 M ass Spectrom etry

3.5 M olecular Reco gnition - Biological Recog nition Agents

3.5.1 Introduction

3.5.2 Enzymes

3.5.3 Tissue M aterials

3.5.4 Micro-Organisms

3.5.5 Mitochondria3.5.6 Antibodies

3.5.7 Nucleic Acids

3.5.8 Receptors

3.6 Imm obilization of Biological Co mponen ts

3.6.1 Introduction

3.6.2 Adsorption

3.6.3 Microencapsulation

3.6.4 Entrapment3.6.5 Cross-Linking

3.6.6 Cov alent Bon ding

Further Reading

Performance Factors

4.1 Introduction

4.2 Selectivity4.2.1 Ion-Selective Electrodes

4.2.2 Enzymes

4.2.3 Antibodies

4.2.4 Receptors

4.2.5 Others

4.3 Sensitivity

4.3.1 Ran ge, Linear Range and Detection Limits

4.4 Time Factors4.4.1 Respo nse Times

4.4.2 Recov ery Times

4.4.3 Lifetimes

4.5 Precision, Accu racy and Repe atability

4.6 Different Biomaterials

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x Chemical Sensors and Biosensors

4.7 Different Transducers 118

4.7.1 Urea Biose nsors 118

4.7.2 Am ino Acid Biosenso rs 120

4.7.3 Gluco se Biosenso rs 120

4.7.4 Uric Ac id 1214.8 Som e Factors Affecting the Performan ce of Sensors 122

4.8.1 Am ount of En zym e 122

4.8.2 Imm obilization M ethod 123

4.8.3 pH of Buffer 123

Further Read ing 124

5 Electrochemical Sensors and Biosensors 125

5.1 Potentiome tric Sensors - Ion-Selective Electrodes 125

5.1.1 Co ncen trations and Activities 125

5.1.2 Ca libration Graphs 127

5.1.3 Exa m ples of Ion-Selective Electrodes 129

5.1.4 Gas Sensors - Gas-S ensing Electrode s 132

5.2 Potentiome tric Biosenso rs 134

5.2.1 pH -Linked 134

5.2.2 Am m onia-Linked 1355.2.3 Carbon Diox ide-Linked 136

5.2.4 Iodin e-Selective 136

5.2.5 Silver Sulfide-Linked 137

5.3 Amperom etric Sensors 138

5.3.1 Direc t Elec trolytic M ethods 138

5.3.2 The Thre e Ge nerations of Biosenso rs 138

5.3.3 First Ge neration - The Oxygen Electrode 140

5.3.4 Second Gen eration - M ediators 142

5.3.5 Third Gen eration - Directly Cou pled Enz ym e

Electrodes 150

5.3.6 NA DH /NA D+ 151

5.3.7 Exam ples of Am perom etric Biosen sors 154

5.3.8 Am perom etric Gas Sensors 160

5.4 Con ductom etric Sensors and Biosensors 163

5.4.1 Che miresistors 163

5.4.2 Biosenso rs Based on Chem iresistors 163

5.4.3 Sem iconducting Oxide Sensors 164

5.5 Applications of Field-Effect Transistor Sen sors 165

5.5.1 Chem ically Sensitive Field-Effect Transistors

(CHEMFETs) 165

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Contents xi

5.5.2 Ion-Se lective Field-Effect Transistors (ISFET s) 166

5.5.3 FE T-B ased Biosens ors (ENFET s) 166

Further Reading 168

6 Photom etric App lications 171

6.1 Tech niques for Optical Sensors 171

6.1.1 Mo des of Op eration of W aveguides in Senso rs 171

6.1.2 Imm obilized Reag ents 173

6.2 Visible Ab sorption Spectroscopy 174

6.2.1 M easurement of pH 17 4 '

6.2.2 M easurem ent of Carbon Dioxide 175

6.2.3 M easurem ent of Am m onia 175

6.2.4 Exa mples That Ha ve Been Use d in Biosenso rs 176

6.3 Fluoresce nt Reag ents 176

6.3.1 Fluoresce nt Reag ents for pH M easurem ents 177

6.3.2 Halides 177

6.3.3 Sodium . 177

6.3.4 Potassium 178

6.3.5 Gas Senso rs 1786.4 Indirect M ethods Using Com petitive Bind ing 178

6.5 R eflectance M ethods - Internal Reflectance Spectroscopy 182

6.5.1 Ev anesce nt W aves 182

6.5.2 Reflectance M ethod s 183

6.5.3 Attenuated Total Reflectance 185

6.5.4 Total Interna l Reflection Flu oresce nce 186

6.5.5 Surface Plasmon Res onance 187

6.6 Light Scattering Techniques 1916.6.1 Types of Ligh t Scattering 191

6.6.2 Qu asi-Elastic Light Scattering Spectroscopy 192

6.6.3 Photon Correlation Spectroscopy 192

6.6.4 Lase r Doppler Velocimetry 193

Further Reading 194

7 M ass-Sensitive and Therm al Sensors 197

7.1 Th e Piezo-E lectric Effect 198

7.1.1 Princ iples 198

7.1.2 Gas Sensor Ap plications 198

7.1.3 Biosenso r Ap plications 200

7.1.4 The Quartz Crystal M icrobalanc e 200

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xii Chemical Sensors and Biosensors

7.2 Surface Acoustic W aves 202

7.2.1 Plate Wave M ode 203

7.2.2 Evanescent Wave M ode 203

7.2.3 Lam b M ode 2037.2.4 Thickness Shear M ode 204

7.3 Th erma l Sensors 205

7.3.1 Therm istors 205

7.3.2 Catalytic Gas Sensors 207

7.3.3 Therm al Conduc tivity Devices 209

Further Read ing 211

8 Specific Ap plication s 213

8.1 Determ ination of Glucose in Blood - Am perom etric Biose nsor 214

8.1.1 Survey of Bio sensor M ethods for the De termination

of Glucose 214

8.1.2 Aim - 214

8.2 De termina tion of Na nog ram Lev els of Copp er(i) in W ater

Using Anodic Stripping Voltammetry, Employing an Electrode

Modified with a Com plexing Agent 2178.2.1 Backgroun d to Stripping Voltammetry - An odic

and Cathod ic 217

8.2.2 Aim 219

8.3 De termina tion of Several Ions Simu ltaneously - 'Th e

Laboratory on a C hip' / 220

8.3.1 Chemiresistors 220

8.3.2 Senso r Array s and 'Sm art' Sensors 221

8.3.3 Backgroun d to Ion-Selective Field-Effect Transistors 2228.3.4 Aim 223

8.4 Determination of Attomole Levels of a Trin itrotoluen e-A ntibod y

Com plex with a Lum inescent Transducer 224

8.4.1 Background to Imm uno -Lu m inesce nt Assays 224

8.4.2 Aim 224

8.5 De termina tion of Flavan ols in Beers 227

8.5.1 Backgroun d 227

8.5.2 Aim 228Further Reading 230

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Contents xiii

Responses to Self-Assessment Questions 233

Bibliography 251

Glossary of Terms 253SI Units and Physical Constants 259

Period ic Table 263

Index 265

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