Proton Transfer Reaction Mass Spectrometry (eBook)

Andrew M Ellis, Department of Chemistry, University of Leicester, Leicester Christopher A Mayhew, School of Physics & Astronomy, University of Birmingham, Birmingham

Quotation xiii

Preface xv

SECTION 1 FUNDAMENTALS

1 Background 3

1.1 Volatile Organic Compounds in the Earth's Atmosphere
3

1.2 Volatile Organic Compounds in Other Environments 5

1.3 Techniques for VOC Measurements 6

1.4 Emergence of Proton Transfer Reaction Mass Spectrometry
15

References 23

2 Chemical Ionization: Chemistry, Thermodynamics and Kinetics
25

2.1 Introduction 25

2.2 Proton Transfer 27

2.3 Other Chemical Ionization Processes 44

References 45

3 Experimental: Components and Principles 49

3.1 Introduction 49

3.2 Ion Extraction and Ion Optics 50

3.3 Ion Sources 57

3.4 Drift Tubes 64

3.5 Mass Spectrometry 76

3.6 Ion Detectors 97

3.7 Analogue versus Digital Signal Processing 103

References 106

4 Quantitative Analysis 111

4.1 Introduction 111

4.2 Extracting the Concentration of a Trace Gas from PTR-MS
111

4.3 Normalized Counts per Second 112

4.4 Why Calibrate? 113

4.5 Calibration Techniques 116

4.6 Effect of Humidity 120

4.7 Accuracy, Precision and Limit of Detection 122

4.8 Validation of PTR-MS 125

References 126

SECTION 2 APPLICATIONS

5 PTR-MS in the Environmental Sciences 131

5.1 Background 131

5.2 Use of Reagent Ions Other Than H3O+ 138

5.3 Biogenic VOCs 141

5.4 Anthropogenic VOCs 156

5.5 Biomass Burning 166

5.6 Applications of PTR-MS to Laboratory Studies of Atmospheric
Chemistry 169

5.7 Plant Studies 178

5.8 Outlook for Atmospheric and Environmental Applications of
PTR-MS 201

References 201

6 PTR-MS in the Food Sciences 219

6.1 Background 219

6.2 Combined GC-MS and PTR-MS Studies for Food Analysis
221

6.3 Mass Spectral Fingerprinting 224

6.4 Flavour Release and Perception 225

6.5 Food Classification, Food Quality and Food Control 243

6.6 Outlook for Food Science and Technology Applications 254

References 255

7 PTR-MS in the Medical Sciences 265

7.1 Background 265

7.2 Breath Analysis 266

7.3 Online PTR-MS Measurements of Volatile Emissions from
Microbial Cultures 288

7.4 Other Medical Applications 295

References 300

8 Applications of PTR-MS to Homeland Security: The Detection
of Threat Agents 309

8.1 Background 309

8.2 Explosives 310

8.3 Chemical Warfare Agents and Toxic Industrial Chemicals
319

8.4 Narcotics 320

8.5 Date Rape Drugs 323

8.6 Ion Mobility Mass Spectrometry and PTR-MS: A Brief
Comparison for Homeland Security Applications 324

8.7 Future Directions 325

References 326

9 Liquid Analysis Using PTR-MS 329

9.1 Determination of Henry's Law Constants Using PTR-MS
329

9.2 Analysis of Liquids 331

References 334

Index