1. Introduction ................................................ 1
1.1. Sensors and Sensor Science ............................ 1
1.1.1. Sensors - Eyes and Ears of Machines ........... 1
1.1.2. The Term 'Sensor' ............................. 3
1.2. Chemical Sensors ...................................... 3
1.2.1. Characteristics of a Chemical Sensor .......... 3
1.2.2. Elements of Chemical Sensors .................. 7
1.2.3. Characterisation of Chemical Sensors ......... 11
1.3. References ........................................... 13
2. Fundamentals ............................................... 15
2.1. Sensor Physics ....................................... 15
2.1.1. Solids ....................................... 15
2.1.2. Optical Phenomena and Spectroscopy ........... 25
2.1.3. Piezoelectricity and Pyroelectricity ......... 37
2.2. Sensor Chemistry ..................................... 38
2.2.1. Chemical Equilibrium ......................... 38
2.2.2. Kinetics and Catalysis ....................... 41
2.2.3. Electrolytic Solutions ....................... 42
2.2.4. Acids and Bases, Deposition Processes and
Complex Compounds ............................ 43
2.2.5. Redox Equilibria ............................. 48
2.2.6. Electrochemistry ............................. 51
2.2.7. Ion Exchange, Solvent Extraction and
Adsorption Equilibria ........................ 72
2.2.8. Special Features of Biochemical Reactions .... 78
2.3. Sensor Technology .................................... 82
2.3.1. Thick-Film Technology ........................ 83
2.3.2. Thin-Film Technology and Patterning
Procedures ................................... 85
2.3.3. Surface Modification and Ordered
Monolayers ................................... 87
2.3.4. Microsystems Technology ...................... 96
2.4. Measurement with Sensors ............................. 99
2.4.1. Primary Electronics for Sensors .............. 99
2.4.2. Instruments for Electric Measurements ....... 103
2.4.3. Optical Instruments ......................... 104
2.5. References .......................................... 112
3. Semiconductor Structures as Chemical Sensors .............. 115
3.1. References .......................................... 117
4. Mass-Sensitive Sensors .................................... 119
4.1. BAW Sensors ......................................... 120
4.2. SAW Sensors ......................................... 121
5. Conductivity Sensors and Capacitive Sensors ............... 123
5.1. Conductometric Sensors .............................. 124
5.2. Resistive and Capacitive Gas Sensors ................ 126
5.2.1. Gas Sensors Based on Polycrystalline
Semiconductors ............................... 126
5.2.2. Gas Sensors Made of Polymers and Gels ........ 129
5.3. Resistive and Capacitive Sensors for Liquids ........ 130
5.4. References .......................................... 132
6. Thermometric and Calorimetric Sensors ..................... 133
6.1. Sensors with Thermistors and Pellistors ............. 133
6.2. Pyroelectric Sensors ................................ 135
6.3. Sensors Based on Other Thermal Effects .............. 136
6.4. References .......................................... 136
7. Electrochemical Sensors ................................... 137
7.1. Potentiometrie Sensors .............................. 138
7.1.1. Selectivity of Potentiometrie Sensors ....... 141
7.1.2. Ion-Selective Electrodes .................... 142
7.1.3. The Ion-Selective Field Effect Transistor
(ISFET) ..................................... 159
7.1.4. Measurement with Potentiometrie Sensors ..... 162
7.2. Amperometric Sensors ................................ 166
7.2.1. Selectivity of Amperometric Sensors ......... 167
7.2.2. Electrode Design and Examples ............... 169
7.3.3. Measurement with Amperometric Sensors ....... 173
7.3. Sensors Based on Other Electrochemical Methods ...... 175
7.4. Electrochemical Biosensors .......................... 175
7.4.1. Fundamentals ................................ 175
7.4.2. Classes of Electrochemical Biosensors ....... 179
7.5. References .......................................... 196
8. Optical Sensors ........................................... 199
8.1. Optical Fibres as a Basis for Optical Sensors ....... 199
8.2. Fibre Sensors Without Chemical Receptors
(Mediators) ......................................... 202
8.3. Optodes: Fibre Sensors with a Chemical Receptor ..... 205
8.3.1. Overview .................................... 205
8.3.2. Optodes with Simple Receptor Layers ......... 208
8.3.3. Optodes with Complex Receptor Layers ........ 211
8.4. Sensors with Planar Optical Transducers ............. 211
8.4.1. Planar Waveguides ........................... 211
8.4.2. Surface Plasmon Resonance and
Resonant-Mirror Prism Couplers .............. 213
8.5. Optical Biosensors .................................. 215
8.5.1. Fundamentals ................................ 215
8.5.2. Optical Enzyme Sensors ...................... 215
8.5.3. Optical Bioaffinity Sensors ................. 218
8.5.4. Optical DNA Sensors ......................... 221
8.6. Sensor Systems with Integrated Optics ............... 223
8.7. References .......................................... 225
9. Chemical Sensors as Detectors and Indicators .............. 227
9.1. Indicators for Titration Processes .................. 227
9.2. Flow-Through Detectors for Continuous Analysers
and for Separation Techniques ....................... 229
9.2.1. Continuous Analysers ........................ 230
9.2.2. Separation Methods .......................... 234
9.3. References .......................................... 239
10. Sensor Arrays and Micro Total Analysis Systems ............ 241
10.1. Two Trends and Their Causes ......................... 241
10.2. Smart Sensors and Sensor Arrays ..................... 242
10.2.1. Intelligence in Sensors ..................... 242
10.2.2. Sensor Arrays ............................... 245
10.3. Micro Total Chemical Analysis Systems (μ-TASs) ...... 253
10.3.1. History ..................................... 253
10.3.2. Technological Aspects ....................... 258
10.3.3. Characteristic Operations and Processes
in Micro Total Analysers .................... 259
10.3.4. Examples of μ-TAS ........................... 262
10.4. References .......................................... 265
Subject Index ................................................. 267
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