An in-depth text that explores the interface between analytical chemistry and trace evidence
Analytical Techniques in Forensic Science is a comprehensive guide written in accessible terms that examines the interface between analytical chemistry and trace evidence in forensic science. With contributions from noted experts on the topic, the text features a detailed introduction analysis in forensic science and then subsequent chapters explore the laboratory techniques grouped by shared operating principles. For each technique, the authors incorporate specific theory, application to forensic analytics, interpretation, forensic specific developments, and illustrative case studies.
Forensic techniques covered include UV-Vis and vibrational spectroscopy, mass spectrometry and gas and liquid chromatography. The applications reviewed include evidence types such as fibers, paint, drugs and explosives. The authors highlight data collection, subsequent analysis, what information has been obtained and what this means in the context of a case. The text shows how analytical chemistry and trace evidence can problem solve the nature of much of forensic analysis. This important text:
Puts the focus on trace evidence and analytical science Contains case studies that illustrate theory in practice Includes contributions from experts on the topics of instrumentation, theory, and case examples Explores novel and future applications for analytical techniques
Written for undergraduate and graduate students in forensic chemistry and forensic practitioners and researchers, Analytical Techniques in Forensic Science offers a text that bridges the gap between introductory textbooks and professional level literature.
List of Contributors xvii Preface xix Acknowledgements xxi Part I Preparing for Analysis 1 1 Introduction to Forensic Science 3 Sue Jickells, Rosalind Wolstenholme and Shari Forbes 1.1 Forensic Science 3 1.2 The Forensic Process 6 1.2.1 Forensic Principles and the Crime Scene 6 1.2.2 Preparatory Issues in Laboratory Analysis 11 1.2.3 Interpretation of Forensic Evidence 13 1.2.3.1 The Expert Witness and Interpretation 14 1.2.3.2 Evidential Value 15 1.2.3.3 Statistical Interpretation 18 1.2.3.4 Bayesian Statistics 20 1.3 Judicial Systems 22 1.3.1 Criminal vs. Civil Law 22 1.3.2 Adversarial vs. Inquisitorial System 24 1.3.3 Rules of Evidence 25 1.3.3.1 Admissibility of Evidence 25 1.3.4 Types of Evidence 26 1.3.5 Opinion and Expert Testimony 28 1.3.5.1 Admissibility of Scientific and Technical Evidence 28 1.4 The Role of Analytical Chemistry in Forensic Science 30 1.4.1 Techniques Used for Chemical Analysis 31 References 32 2 Analytical Methodology and Experimental Design 35 Florian Wulfert and Rosalind Wolstenholme 2.1 Scientific Method 35 2.2 What DoWe Mean by Analysis? 36 2.3 The Stages of Analysis 36 2.3.1 Quantification 37 2.3.1.1 External Standards 37 2.3.1.2 Internal Standards 38 2.3.1.3 Standard Addition 38 2.4 Analysis Development 39 2.4.1 Error Estimation 39 2.4.2 Quality Assurance and Quality Control 40 2.4.3 Method Development and Experimental Designs 41 2.4.4 Selecting Critical Variables with Factorial Designs 42 2.4.4.1 Categorical Variables 43 2.4.4.2 Reduced Designs 44 2.4.4.3 Final Practical Experimental Considerations 44 2.4.4.4 Deciding on Significance 44 2.4.4.5 Interpretation 45 2.4.5 Modelling the Significant Variables Using Response Surface Designs 46 2.4.5.1 Sparse Response Surface Designs 48 2.4.5.2 Analysing Response Surface Models 48 2.4.5.3 Validation 49 2.4.5.4 Optimisation 49 3 Presumptive Testing 51 Rosalind Wolstenholme and Shari Forbes 3.1 Introduction 51 3.2 Drugs 52 3.2.1 Drugs Seizure Sampling 52 3.2.2 Major Drug Classes 52 3.2.2.1 Marijuana 52 3.2.2.2 Opioids, Cocaine, and Amphetamines 53 3.2.2.3 Barbiturates and Benzodiazepines 53 3.2.2.4 LSD 53 3.2.2.5 New Psychoactive Substances 55 3.2.3 Presumptive Tests for Drugs 56 3.2.3.1 Colour Tests 56 3.2.3.2 Thin Layer Chromatography 56 3.2.3.3 Microcrystal Tests 56 3.3 Firearms Discharge Residue 57 3.3.1 Firearms Discharge Residue Sampling 57 3.3.2 Firearms Discharge Residue Presumptive Tests 58 3.4 Explosives 59 3.4.1 Explosive Residue Sampling 60 3.4.2 Explosive Residue Presumptive Tests 60 3.4.2.1 Colour Tests 60 3.4.2.2 Thin Layer Chromatography 61 3.4.2.3 Portable Instruments 61 3.5 Ethanol (Ethyl Alcohol) 61 3.5.1 Breath Alcohol Testing 61 3.5.1.1 Electronic Devices 62 3.5.1.2 Chemical Test Devices 63 3.5.2 Saliva-Based Testing 63 3.6 Ignitable Liquid Residues 64 3.7 Non-Chemical Presumptive Tests 65 3.7.1 Electronic Detectors 65 3.7.1.1 Electronic Detectors for Fire Investigations 65 3.7.1.2 Electronic Detectors for Explosives and Illicit Drugs 66 3.7.2 Canine Detection 67 References 68 4 Sample Preparation 71 Sue Jickells 4.1 Sample Preparation 71 4.2 Extraction 75 4.2.1 Solvent Extraction 76 4.2.2 Liquid–Liquid Extraction 77 4.2.3 Solid Phase Extraction 82 4.2.3.1 Stationary Phases 85 4.2.3.2 Normal Phase 92 4.2.3.3 Reversed Phase 93 4.2.3.4 Ion Exchange 95 4.2.3.5 Molecularly Imprinted Polymers 95 4.2.3.6 Immunoaffinity SPE 97 4.2.4 Solid-Phase Microextraction 97 4.2.5 QuEChERS 101 4.2.6 Sample Handling Post Extraction 101 4.2.6.1 Solvent Evaporation 101 4.2.6.2 Derivatisation 102 4.3 Sample Preparation for Inorganic Analyses 102 4.3.1 Total Analysis 103 4.3.2 Chemical Speciation 105 4.4 DNA Profiling 105 4.5 Conclusion 106 References 106 Part II Spectroscopic and Spectrometric Techniques 109 5 The Electromagnetic Spectrum 111 Rosalind Wolstenholme Reference 114 6 Ultraviolet–Visible and Fluorescence Spectroscopy 115 Rosalind Wolstenholme 6.1 Forensic Introduction 115 6.2 Theory 115 6.2.1 Electronic Transitions 115 6.2.2 Photoluminescence and Fluorescence 118 6.2.3 Quantification 120 6.2.3.1 UV-Vis Quantification 120 6.2.3.2 Fluorescence Quantification 121 6.3 Instrumentation 122 6.3.1 UV-Vis Spectrometers 122 6.3.2 Fluorescence Spectrometers/Fluorometers 123 6.3.3 Coupling Techniques 126 6.3.4 Microspectrophotometers 126 6.3.5 Hyperspectral Imaging 126 6.3.6 Filtered Light Examination 127 6.4 Application to Analyte 128 6.4.1 Transmission Analysis in Solution 128 6.4.1.1 UV-Vis Solution Analysis 128 6.4.1.2 Fluorescent Solution Analysis 129 6.4.2 MSP Sample Preparation 129 6.4.3 Acquiring a Spectrum 130 6.4.3.1 Capture of Spectra in Solution 130 6.4.3.2 MSP and HSI Sample Analysis 131 6.4.4 Forensic Applications 131 6.4.4.1 Writing Ink Examination 132 6.4.4.2 Fibre Examination 133 6.5 Interpretation and Law 134 6.5.1 Interpreting UV-Vis Spectra 135 6.5.2 Interpreting Fluorescence Spectra 137 6.5.3 UV-Vis and Fluorescence Spectroscopy in Court 138 6.6 Case Studies 138 6.6.1 Case Study 1 138 6.6.2 Case Study 2 139 6.7 Forensic Developments 140 References 140 7 Infrared Spectroscopy 145 Barbara Stuart 7.1 Introduction 145 7.2 Theory of the Technique 145 7.2.1 Basis of the Technique 145 7.2.2 Instrumentation 146 7.2.3 Transmission Spectroscopy 148 7.2.4 Reflectance Spectroscopy 148 7.2.5 Infrared Microspectroscopy 150 7.2.6 Handheld and Portable Instruments 151 7.3 Application to Analyte 151 7.3.1 Sampling 151 7.3.2 Spectrum Analysis 152 7.4 Interpretation and Law 155 7.5 Case Studies – Discrimination of Acrylic Fibres 157 7.6 Forensic Developments 158 References 159 8 Raman Spectroscopy 161 Rosalind Wolstenholme 8.1 Forensic Introduction 161 8.2 Theory 161 8.2.1 Raman Scattering 161 8.2.2 Modes of Vibration 163 8.2.3 Raman Shift 165 8.2.4 Raman Instrumentation 166 8.2.4.1 Lasers, Fluorescence, and Resolution 166 8.2.4.2 Dispersive versus FT 167 8.2.4.3 Dispersive Raman Spectrometers 168 8.2.4.4 FT-Raman Spectrometers 169 8.2.4.5 Polarisers 169 8.2.4.6 Microscopes and Imaging 169 8.2.4.7 Portable Instruments and Probes 170 8.2.4.8 Quantitation 170 8.2.5 Advanced Techniques 171 8.2.5.1 Resonance Raman Spectroscopy 171 8.2.5.2 SERS/SERRS 171 8.2.5.3 SORS 172 8.2.6 Advantages and Disadvantages of Raman Spectroscopy 173 8.3 Application to Analyte 174 8.3.1 Acquiring a Spectrum 174 8.3.2 Forensic Applications 175 8.3.2.1 Pen Ink 175 8.3.2.2 Paint 175 8.3.2.3 Drugs of Abuse 176 8.4 Interpretation and Law 177 8.4.1 Interpreting Raman Spectra 177 8.4.2 Raman Spectroscopy in Court 179 8.5 Case Studies 180 8.5.1 Case Study 1 180 8.5.2 Case Study 2 180 8.6 Forensic Developments 181 References 181 9 Scanning Electron Microscopy 185 Grzegorz Zadora and Aleksandra Michalska 9.1 Introduction 185 9.2 Theory of the Technique 186 9.2.1 Scanning Electron Microscope 186 9.2.2 X-Ray Detection 191 9.2.3 Operating Conditions 192 9.2.4 Specimen Preparation 193 9.2.4.1 Vacuum Evaporation 194 9.3 Application to Analyte(s) 195 9.3.1 Gunshot Residue 196 9.3.2 Glass 200 9.3.3 Other Samples 203 9.4 Interpretation and Law 203 9.4.1 Evidence Evaluation on Source Level 203 9.4.2 Evidence Evaluation on Activity Level 206 9.5 Case Study 207 9.5.1 GSR – Case Study 207 9.5.2 Glass – Comparison and Classification Problem 209 9.5.3 Glass –Was the Car Bulb Switched on During the Accident? 212 References 214 10 Mass Spectrometry 219 Mark C. Parkin and Alan Brailsford 10.1 Introduction 219 10.1.1 Forensic Application of Mass Spectrometry 221 10.2 Theory of the Technique 223 10.2.1 Principles of Mass Spectrometry 223 10.2.2 Sample Introduction 224 10.2.3 Modes of Sample Ionisation 225 10.2.3.1 Electron Ionisation 225 10.2.3.2 Chemical Ionisation 227 10.2.3.3 Electrospray Ionisation 230 10.2.3.4 Atmospheric Pressure Chemical Ionisation 231 10.2.3.5 Desorption and Ambient Methods 232 10.2.3.6 Matrix-Assisted Laser Desorption/Ionisation 232 10.2.3.7 Secondary Ion Mass Spectrometry 234 10.2.3.8 Desorption Electrospray Ionisation 234 10.2.3.9 Direct Analysis in Real Time 234 10.2.4 Ion Separation – Mass Analysers 235 10.2.4.1 Mass Range, Resolution and Accuracy 235 10.2.4.2 Magnetic Sector 236 10.2.4.3 Quadrupoles – Quadrupole Mass Filter 236 10.2.4.4 Quadrupole Ion Trap 237 10.2.4.5 Time of Flight 238 10.2.4.6 Fourier Transform Instruments – Ion Cyclotron Resonance 239 10.2.4.7 Fourier Transform Instruments – Orbitrap 240 10.2.4.8 Tandem Mass Spectrometry – Ion Fragmentation by Collision Induced Dissociation 241 10.2.4.9 Tandem Mass Analysers – Ion Traps 242 10.2.4.10 Tandem Mass Analysers – Triple Quadrupoles 242 10.2.4.11 Tandem Mass Analysers – Hybrid Instruments 242 10.2.5 Ion Detection 243 10.2.5.1 Electron Multipliers 243 10.2.5.2 Faraday Cup 244 10.2.6 Anatomy of a Mass Spectrum 244 10.2.6.1 The Molecular or Quasi-Molecular Ion 245 10.2.6.2 The Fragment Region 247 10.2.6.3 Full Scan Mass Spectra 247 10.2.6.4 Product Ion Spectra 248 10.2.6.5 Extracted Ion Chromatograms 248 10.2.6.6 Selected Ion Chromatograms and Multiple Reaction Monitoring 249 10.2.6.7 Precursor Ion Detection and Neutral Loss Scanning 252 10.3 Application to Analytes 252 10.4 Interpretation and Law 254 10.4.1 Chain of Custody 254 10.4.2 New Forensic Regulations 255 10.4.3 ID Criteria – Screen and Confirmation 255 10.4.4 Chromatographic Criteria 256 10.4.5 Mass Spectrometric Identification Criteria 256 10.5 Case Studies 257 10.5.1 Serial Killing by Poisoning 257 10.5.2 Surreptitious Insulin Administration 257 10.6 Forensic Developments 258 10.6.1 Beyond Blood and Urine 258 10.6.2 High Mass Accuracy Mass Spectrometry 259 10.6.3 Mobile Mass Spectrometers 260 References 261 11 Isotope Ratio Mass Spectrometry 267 Sarah Benson and Kylie Jones 11.1 Forensic Introduction 267 11.2 Basis of the Technique 268 11.2.1 Isotopes 268 11.2.2 Isotopic Abundance and Delta Notation 268 11.2.3 Standards and Reference Materials 269 11.2.4 Isotopic Variability – Fractionation and Mixing 270 11.2.5 Isotopic Variability of Natural Materials 272 11.2.6 Instrumentation: Stable Isotope Ratio Mass Spectrometers 272 11.3 Introduction to the Isotope Ratio Mass Spectrometer 276 11.3.1 IRMS – Detection and Measurement 276 11.3.2 Sample Preparation 277 11.3.3 Bulk Stable Isotope Analysis 277 11.3.4 Bulk Measurements by Quantitative High Temperature Combustion 278 11.3.5 Bulk Measurements by Quantitative High Temperature Conversion 279 11.3.6 Compound Specific Isotope Analysis 279 11.4 Interpretation 280 11.5 Case Studies 281 11.6 Applications in Forensic Science 283 11.6.1 Distinguishing between Naturally Occurring and Synthetic Materials in Doping, e.g. Endogenous and Exogenous (Synthetic) Testosterone 284 11.6.2 Determining Authenticity and Predicting Geographical Origin of Food, Pharmaceuticals and Other Materials, e.g. Counterfeiting 284 11.6.3 Tracing the Geographic Origin and Movement of Wildlife, Persons and Materials 284 11.6.4 Identifying the Source of Environmental Contaminants 285 11.6.5 Determining the Geographical Origin of Plant Materials, e.g. Natural Illicit Drugs – Cannabis, Cocaine, and Heroin 285 11.6.6 Characterising Microorganisms 286 11.6.7 Determining Synthetic Pathways Used to Manufacture Illicit Drugs, e.g. Ecstasy and MDMA, Methamphetamine, and Amphetamine 286 11.6.8 Distinguishing between Two or More Samples of a Material to Infer Source or a Common Origin 287 11.6.9 Distinguishing Between Two or More Samples of Ignitable Liquids and Chemicals 287 11.6.10 Determining Source Through Association of Starting Materials and End Products, e.g. Explosives 288 11.7 Future of IRMS and Stable Isotopic Comparisons 288 References 288 Part III Chromatographic Techniques 295 12 Chromatographic Separation and Theory 297 Sue Jickells and Shari Forbes 12.1 Introduction 297 12.2 Chromatography 298 12.2.1 Planar Chromatography 299 12.2.2 Column Chromatography 300 12.3 The Separation Process 300 12.3.1 Distribution Constant 303 12.3.2 Hold-Up Time (or Volume) 304 12.3.3 Retention Time (or Volume) 305 12.3.3.1 Retention Time and Sample Concentration 306 12.3.4 Retention Factor 306 12.3.5 Separation Factor 307 12.4 Separation Theory 307 12.4.1 Plate Theory 307 12.4.2 Theory versus Practice: Band Broadening 308 12.4.3 Rate Theory 311 12.4.3.1 Eddy Diffusion (A) 312 12.4.3.2 Longitudinal Diffusion (B) 313 12.4.3.3 Mass Transfer (C) 314 12.4.3.4 Non-Column Parameters Contributing to Band Broadening 316 12.5 Practical Applications of Chromatographic Theory 316 12.5.1 Optimising Chromatographic Separations 317 12.5.1.1 Resolution 317 12.5.1.2 GC 319 12.5.1.3 Mobile Phase 320 12.6 Conclusion 323 References 323 13 Gas Chromatography 327 Shari Forbes 13.1 Introduction 327 13.2 Gas Chromatography Components 327 13.2.1 Mobile Phase System 328 13.2.2 Sample Injection System 329 13.2.2.1 Liquid Samples 330 13.2.2.2 Gases and Volatile Compounds 334 13.2.2.3 Gas Samples 334 13.2.2.4 Volatile Compounds: Headspace Analysis 335 13.2.2.5 Static Headspace Analysis 335 13.2.2.6 Dynamic Headspace Analysis 336 13.2.2.7 Pyrolysis GC 338 13.2.3 Columns and Chromatographic Separation 338 13.2.3.1 Column Selection 340 13.2.3.2 Column Temperature and Programming 341 13.2.4 Detectors and Detection Systems 343 13.2.4.1 Flame Ionisation Detectors 344 13.2.4.2 Electron Capture Detectors 345 13.2.4.3 Nitrogen–Phosphorous Detectors 345 13.2.4.4 Mass Spectrometric Detection Systems 346 13.3 Application to Analyte 348 13.3.1 Sample Derivatisation 348 13.3.2 Qualitative Analysis 350 13.3.3 Quantitative Analysis 351 13.3.3.1 Methods of Quantitative Analysis 353 13.4 Interpretation and Law 354 13.5 Case Studies 356 13.5.1 Case Study 1 356 13.5.2 Case Study 2 357 13.6 Forensic Developments 358 13.6.1 Multidimensional GC 358 13.6.2 Portable GC 361 References 362 14 High Performance Liquid Chromatography and Ultra-High Performance Liquid Chromatography Including Liquid Chromatography–Mass Spectrometry 365 Sophie Turfus and Luke N. Rodda 14.1 Introduction 365 14.2 Components of an HPLC instrument and their Optimisation 368 14.2.1 Pump and Mixer 368 14.2.2 Autosampler and Inlet 370 14.2.3 Injector 370 14.2.4 Column 370 14.2.4.1 Stationary Phase 371 14.2.4.2 Column Dimensions 373 14.2.4.3 Particle Size 373 14.2.4.4 Pre-Column/Guard Column 373 14.2.5 Fittings 374 14.2.6 Mobile Phase 375 14.2.6.1 Mobile Phase A 376 14.2.6.2 Mobile Phase B 376 14.2.7 Effect of Temperature/Flow Rate 379 14.2.8 Detector 380 14.2.8.1 Mass Spectrometer 380 14.2.8.2 UV Detector 382 14.2.8.3 PDA Detector 383 14.3 Related Techniques 384 14.3.1 Ion Chromatography 384 14.3.2 Affinity Chromatography 384 14.3.3 Chiral Chromatography 385 14.4 Chromatography Theory 385 14.5 Detection 386 14.6 Coupling of Liquid Chromatography to Mass Spectrometry 388 14.7 Types of Analytes 390 14.7.1 Basic Analytes 390 14.7.2 Acidic Analytes 390 14.7.3 Proteins 391 14.7.4 DNA 391 14.7.5 Chiral Compounds 392 14.7.6 Bulk Drugs and High-Concentration Analytes 392 14.7.7 Low-Concentration Analytes 392 14.8 Accreditation and Method Validation 393 14.8.1 Use of Internal Standards 393 14.8.2 Effect of Sample Matrix 394 14.8.3 Ion Ratios 394 14.9 Interpretation of Results in the Forensic and Legal Context 394 14.10 Case Studies 396 14.10.1 Case Study 1: Post-Mortem Death Investigation – Poly-Drug Overdose 396 14.10.2 Case Study 2: Post-Mortem Death Investigation – No Derivatisation Needed for LC-MS 397 14.10.3 Case Study 3: Driving Under the Influence of Drugs – Increased Sensitivity with LC-MS 398 14.11 Forensic Developments 399 14.11.1 Column Switching and Two-Dimensional HPLC 399 14.11.2 Capillary Liquid Chromatography 401 14.11.3 Column-on-a-Chip Technologies 401 14.12 Conclusion 402 References 402 15 Capillary and Microchip Electrophoresis 407 Lucas Blanes, Ellen Flávia Moreira Gabriel, Renata Mayumi Saito, Wendell Karlos Tomazelli Coltro, Nerida Cole, Philip Doble, Claude Roux and Robson Oliveira dos Santos 15.1 Capillary Electrophoresis: Introduction 407 15.2 Microchip-Capillary Electrophoresis 410 15.2.1 Sample Injection Modes in ME 410 15.3 Detection Systems 411 15.4 CE and ME in Forensic Analysis 412 15.5 Case Study: Lab-on-a-Chip Screening of Methamphetamine and Pseudoephedrine in Clandestine Laboratory Samples 412 15.5.1 Screening of Methamphetamine and Pseudoephedrine from Clandestine Laboratories 416 15.5.2 Interferents 416 15.5.3 Simulated Surface Swabs 418 15.6 Conclusions 418 Acknowledgements 419 References 419 Index 425
ROSALIND WOLSTENHOLME, BSC, MSC, PhD, is a senior lecturer in analytical science in the Department of Biosciences and Chemistry, Sheffield Hallam University, UK. SUE JICKELLS, BSC, MSC, PhD, is a retired analytical chemist, formerly at the University of East Anglia and King's College London. SHARI FORBES, BSC, PhD, is a forensic scientist and researcher with the Department of Chemistry, Biochemistry and Physics, University of Quebec Trois-Rivières, Canada.
