Mass Spectrometry for the Analysis of Pesticide Residues and their Metabolites (Wiley Series on Mass Spectrometry)

Provides an overview of the use of mass spectrometry (MS) for the analysis of pesticide residues and their metabolites.* Presents state of the-art MS techniques for the identification of pesticides and their transformation products in food and environment * Covers important advances in MS techniques including MS instrumentation and chromatographic separations (e.g. UPLC, HILIC, comprehensive GCxGC) and applications * Illustrates the main sample preparation techniques (SPE, QuEChERS, microextraction) used in combination with MS for the analysis of pesticides * Describes various established and new ionization techniques as well as the main MS platforms, software tools and mass spectral libraries Title Page 5 Copyright Page 6 Contents 7 List of Contributors 13 Foreword 15 Preface 17 Chapter 1 Pesticide Chemistry and Risk Assessment 19 1.1 INTRODUCTION 19 1.2 PESTICIDE CHEMISTRY 20 1.2.1 Historical Perspective 20 1.2.2 Identity and Physicochemical Properties of Pesticides 20 1.2.3 Pesticide Classification 22 1.2.4 Modes of Action (MoA) 23 1.3 PESTICIDE METABOLITES AND TRANSFORMATION PRODUCTS 26 1.3.1 Biotransformation 27 1.3.2 Environmental Fate 31 1.4 RISK ASSESSMENT 32 1.4.1 Safety Factors 32 1.4.2 Ecological Risk Assessment for Pesticides 33 1.5 DIETARY EXPOSURE TO PESTICIDES 35 1.5.1 Acute Exposure or Short-Term Intake 36 1.5.2 Chronic Exposure or Long-Term Intake 36 1.5.3 Cumulative Exposure to Multiple Substances 36 1.6 PESTICIDE RESIDUES IN FOOD 37 1.6.1 Maximum Residue Limits 37 1.6.2 Residue Definition 38 1.6.3 Reporting of Results 46 1.6.4 Residue Analysis 46 REFERENCES 47 Chapter 2 Legislation, Monitoring, and Analytical Quality Control for Pesticide Residues 53 2.1 INTRODUCTION 53 2.2 FOOD SAFETY 54 2.2.1 CAC of Food and Agriculture Organization/World Health Organization 54 2.2.2 EU Legislation 54 2.2.3 US Food Regulations 58 2.3 WATER QUALITY 62 2.3.1 WHO 62 2.3.2 EU Water Framework Directive 62 2.3.3 US EPA Legislation 64 2.4 METHOD VALIDATION AND QUALITY CONTROL PROCEDURES FOR PESTICIDE RESIDUES ANALYSIS 64 2.4.1 CAC Guidelines 64 2.4.2 EU Guidelines: SANCO Document 65 2.4.3 FDA and EPA Guidelines 66 REFERENCES 68 Chapter 3 Advanced Sample Preparation Techniques for MS Analysis 71 3.1 INTRODUCTION 71 3.2 CONVENTIONAL EXTRACTION AND CLEANUP PROCEDURES 72 3.2.1 LLE 72 3.2.2 SPE 79 3.2.3 MSPD 81 3.2.4 QuEChERS 81 3.3 MICROEXTRACTION TECHNIQUES 83 3.3.1 Sorbent-Based Microextraction Techniques 83 3.3.2 Liquid-Based Microextraction Techniques 89 3.4 ALTERNATIVE EXTRACTION AND CLEANUP PROCEDURES 91 3.4.1 Alternative Energy Sources to Enhance the Extraction 91 3.4.2 Coupled-Column Liquid Chromatography (LC/PC, LC/LC Techniques) 97 3.4.3 Direct Analysis in Real Time 98 3.5 CONCLUSIONS 99 ACKNOWLEDGMENTS 100 REFERENCES 100 Chapter 4 Recent Developments in Gas Chromatography–Mass Spectrometry 109 4.1 INTRODUCTION 109 4.2 ADVANCES IN GC SEPARATIONS 109 4.2.1 Multidimensional and Comprehensive Two-Dimensional Gas Chromatography 110 4.2.2 Fast GC 112 4.2.3 LPGC 113 4.3 MASS SPECTROMETRIC IONIZATION TECHNIQUES 114 4.3.1 Electron Impact Ionization (EI) 115 4.3.2 CI (Positive/Negative Modes) 115 4.3.3 Atmospheric Pressure GC–MS 116 4.4 MASS ANALYZERS INTERFACED TO GC 117 4.4.1 Quadrupole Mass Analyzer 118 4.4.2 Ion Trap Mass Analyzer 118 4.4.3 QqQ 118 4.4.4 TOF 120 4.5 MASS SPECTRAL LIBRARIES AND SOFTWARE APPROACHES IN GC–MS ANALYSIS 121 4.6. MATRIX EFFECTS IN GC–MS ANALYSIS 124 4.7 CONCLUSIONS AND PERSPECTIVES 126 REFERENCES 126 Chapter 5 Recent Developments in Liquid Chromatography–Mass Spectrometry: Advances in Liquid Chromatographic Separations and Ionization Techniques/Interfaces 131 5.1 INTRODUCTION 131 5.2 ADVANCES IN LIQUID CHROMATOGRAPHIC SEPARATIONS 132 5.2.1 Ultraperformance Liquid Chromatography 134 5.2.2 Hydrophilic Interaction Liquid Chromatography 135 5.3 IONIZATION TECHNIQUES/INTERFACES 135 5.3.1 Atmospheric Pressure Ionization Techniques 136 5.3.2 Direct Electron Ionization 139 5.4 AMBIENT IONIZATION TECHNIQUES 140 5.4.1 DESI, Paper Spray, and Low-Temperature Plasma Ambient Ionization 140 5.4.2 Direct Analysis in Real Time 142 5.4.3 Atmospheric Pressure Glow-Discharge Ionization 143 5.5 SUMMARY 143 REFERENCES 143 Chapter 6 Recent Developments in Liquid Chromatography–Mass Spectrometry: Mass Detectors 149 6.1 INTRODUCTION: MASS SPECTROMETERS 149 6.1.1 Triple Quadrupole Mass Analyzer 150 6.1.2 Quadrupole Ion Trap and Triple Quadrupole Linear Ion Trap 153 6.1.3 TOF Mass Analyzer 156 6.1.4 Hybrid TOF 158 6.1.5 Orbitrap Mass Analyzer 160 6.2 COMPARISON AND COMPLEMENTARITIES OF DIFFERENT MASS ANALYZERS IN THE LC–MS ANALYSIS OF PESTICIDE RESIDUES AND THEIR METABOLITES 165 6.2.1 Dynamic Range 165 6.2.2 Scan Rate 165 6.2.3 LODs 166 6.2.4 Mass Accuracy 166 6.2.5 Resolution 167 6.2.6 Selectivity 167 6.2.7 Mass Range 168 6.2.8 Fragmentation 168 6.2.9 Identification Capabilities 168 6.2.10 Quantification 169 6.3 USE OF SOFTWARE TECHNIQUES AND SPECTRAL LIBRARIES IN LC–MS 170 ACKNOWLEDGMENTS 172 REFERENCES 172 Chapter 7 Matrix Effects in Liquid Chromatography–Electrospray Ionization–Mass Spectrometry 179 7.1 INTRODUCTION 179 7.1.1 Some Definitions 179 7.1.2 Differences between Matrix Effects in GC and LC Methods 180 7.1.3 Differences between ESI and Other API Methods 180 7.1.4 A Typical Alarming Situation 181 7.2 DETECTION OF MATRIX EFFECTS 182 7.2.1 Calibration in Solvent versus Matrix-Matched Calibration 182 7.2.2 Postcolumn Infusion 183 7.2.3 Stable Isotope-Labeled Standards 184 7.3 REDUCTION OF MATRIX EFFECTS 184 7.3.1 Change of LC Conditions 184 7.3.2 Change of MS Conditions 184 7.3.3 Better Cleanup 187 7.3.4 Backflush of LC Columns 188 7.3.5 Dilute-and-Shoot 189 7.4 COMPENSATION OF MATRIX EFFECTS 190 7.4.1 Internal standards (IS) 190 7.4.2 Matrix-Matched Standards 192 7.4.3 Postcolumn Infusion 192 7.4.4 Standard Addition 193 7.5 AN ATTEMPT TO EXPLAIN MATRIX EFFECTS 194 7.5.1 Substance Classes Causing Matrix Effects 194 7.5.2 Tentative Mechanisms of Matrix Effects 194 7.5.3 A Recent View on the Mechanism of Ion Suppression 196 REFERENCES 198 Chapter 8 Liquid Chromatography–Mass Spectrometry Analysis of Pesticide Residues and Their Metabolites in Food Samples 205 8.1 INTRODUCTION 205 8.2 APPLICATION OF LC-QQQ-MS/MS FOR THE TARGETED ANALYSIS OF PESTICIDE RESIDUES AND THEIR METABOLITES IN FOOD SAMPLES 207 8.2.1 Sensitivity 210 8.2.2 Linearity 211 8.2.3 Matrix Effects 211 8.3 APPLICATION OF LC–HRMS TO THE ANALYSIS OF PESTICIDE RESIDUES AND THEIR METABOLITES IN FOOD SAMPLES 213 8.3.1 Detection and Identification 213 8.3.2 Resolution 215 8.3.3 MS/MS Identification 218 8.3.4 Sensitivity 219 8.3.5 Linearity 219 8.3.6 Matrix Effect 220 8.4. DATA PROCESSING: AUTOMATED DATABASE SEARCHES 220 8.5 CONCLUSIONS AND FUTURE DEVELOPMENTS 221 REFERENCES 221 Chapter 9 Application of LC-MS/MS and LC-TOF-MS for the Identification of Pesticide Residues and Their Metabolites in Environmental Samples 225 9.1 INTRODUCTION AND OCCURRENCE OF PESTICIDES IN ENVIRONMENTAL SAMPLES 225 9.2 STATE-OF-THE-ART TECHNIQUES FOR THE IDENTIFICATION OF PESTICIDES AND THEIR DEGRADATION PRODUCTS 226 9.2.1 LC–MS/MS for the Analysis of Target Compounds 226 9.2.2 LC-TOF-MS and LC-QTOF-MS for the Analysis of Target and Nontarget Compounds 227 9.3 USE OF ACCURATE MASS TOOLS FOR THE IDENTIFICTION OF PESTICIDE RESIDUES AND THEIR METABOLITES IN FOOD AND WATER SAMPLES 233 9.3.1 Molecular Features 233 9.3.2 Accurate Mass Filters and Isotopic Mass Defect 238 9.3.3 Diagnostic Ion Approach 239 9.3.4 Accurate Mass Databases 241 9.3.5 Accurate Mass Profiling 243 9.4 CONCLUSIONS 245 REFERENCES 245 Chapter 10 Mass Spectrometric Techniques for the Determination of Pesticide Transformation Products Formed by Advanced Oxidation Processes 249 10.1 INTRODUCTION 249 10.2 SAMPLE PREPARATION 250 10.3 HYPHENATED MS TECHNIQUES 255 10.3.1 Low-Resolution Mass Spectrometry: Single-Stage Quadrupole 256 10.3.2 Identification of Pesticide TPs by GC–MS 256 10.3.3 Identification of Pesticide TPs by LC–MS 258 10.3.4 Identification of Pesticide TPs by the Combination of GC–MS and LC–MS 259 10.4 TANDEM MS 259 10.4.1 Identification of Pesticide TPs by QqQ–MS 261 10.4.2 Identification of Pesticide TPs by IT–MS 262 10.5 HRMS 267 10.5.1 Single Mass Analyzer 267 10.5.2 Hybrid HR Mass Spectrometers 273 10.6 CONCLUSIONS AND PERSPECTIVES 274 REFERENCES 277 Index 281 Series Page 289 EULA 291