Analytical Techniques in Forensic Science

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.

• List of Contributors xviiPreface xixAcknowledgements xxiPart I Preparing for Analysis 11 Introduction to Forensic Science 3Sue Jickells, Rosalind Wolstenholme and Shari Forbes1.1 Forensic Science 31.2 The Forensic Process 61.2.1 Forensic Principles and the Crime Scene 61.2.2 Preparatory Issues in Laboratory Analysis 111.2.3 Interpretation of Forensic Evidence 131.2.3.1 The Expert Witness and Interpretation 141.2.3.2 Evidential Value 151.2.3.3 Statistical Interpretation 181.2.3.4 Bayesian Statistics 201.3 Judicial Systems 221.3.1 Criminal vs. Civil Law 221.3.2 Adversarial vs. Inquisitorial System 241.3.3 Rules of Evidence 251.3.3.1 Admissibility of Evidence 251.3.4 Types of Evidence 261.3.5 Opinion and Expert Testimony 281.3.5.1 Admissibility of Scientific and Technical Evidence 281.4 The Role of Analytical Chemistry in Forensic Science 301.4.1 Techniques Used for Chemical Analysis 31References 322 Analytical Methodology and Experimental Design 35Florian Wulfert and Rosalind Wolstenholme2.1 Scientific Method 352.2 What DoWe Mean by Analysis? 362.3 The Stages of Analysis 362.3.1 Quantification 372.3.1.1 External Standards 372.3.1.2 Internal Standards 382.3.1.3 Standard Addition 382.4 Analysis Development 392.4.1 Error Estimation 392.4.2 Quality Assurance and Quality Control 402.4.3 Method Development and Experimental Designs 412.4.4 Selecting Critical Variables with Factorial Designs 422.4.4.1 Categorical Variables 432.4.4.2 Reduced Designs 442.4.4.3 Final Practical Experimental Considerations 442.4.4.4 Deciding on Significance 442.4.4.5 Interpretation 452.4.5 Modelling the Significant Variables Using Response Surface Designs 462.4.5.1 Sparse Response Surface Designs 482.4.5.2 Analysing Response Surface Models 482.4.5.3 Validation 492.4.5.4 Optimisation 493 Presumptive Testing 51Rosalind Wolstenholme and Shari Forbes3.1 Introduction 513.2 Drugs 523.2.1 Drugs Seizure Sampling 523.2.2 Major Drug Classes 523.2.2.1 Marijuana 523.2.2.2 Opioids, Cocaine, and Amphetamines 533.2.2.3 Barbiturates and Benzodiazepines 533.2.2.4 LSD 533.2.2.5 New Psychoactive Substances 553.2.3 Presumptive Tests for Drugs 563.2.3.1 Colour Tests 563.2.3.2 Thin Layer Chromatography 563.2.3.3 Microcrystal Tests 563.3 Firearms Discharge Residue 573.3.1 Firearms Discharge Residue Sampling 573.3.2 Firearms Discharge Residue Presumptive Tests 583.4 Explosives 593.4.1 Explosive Residue Sampling 603.4.2 Explosive Residue Presumptive Tests 603.4.2.1 Colour Tests 603.4.2.2 Thin Layer Chromatography 613.4.2.3 Portable Instruments 613.5 Ethanol (Ethyl Alcohol) 613.5.1 Breath Alcohol Testing 613.5.1.1 Electronic Devices 623.5.1.2 Chemical Test Devices 633.5.2 Saliva-Based Testing 633.6 Ignitable Liquid Residues 643.7 Non-Chemical Presumptive Tests 653.7.1 Electronic Detectors 653.7.1.1 Electronic Detectors for Fire Investigations 653.7.1.2 Electronic Detectors for Explosives and Illicit Drugs 663.7.2 Canine Detection 67References 684 Sample Preparation 71Sue Jickells4.1 Sample Preparation 714.2 Extraction 754.2.1 Solvent Extraction 764.2.2 Liquid–Liquid Extraction 774.2.3 Solid Phase Extraction 824.2.3.1 Stationary Phases 854.2.3.2 Normal Phase 924.2.3.3 Reversed Phase 934.2.3.4 Ion Exchange 954.2.3.5 Molecularly Imprinted Polymers 954.2.3.6 Immunoaffinity SPE 974.2.4 Solid-Phase Microextraction 974.2.5 QuEChERS 1014.2.6 Sample Handling Post Extraction 1014.2.6.1 Solvent Evaporation 1014.2.6.2 Derivatisation 1024.3 Sample Preparation for Inorganic Analyses 1024.3.1 Total Analysis 1034.3.2 Chemical Speciation 1054.4 DNA Profiling 1054.5 Conclusion 106References 106Part II Spectroscopic and Spectrometric Techniques 1095 The Electromagnetic Spectrum 111Rosalind WolstenholmeReference 1146 Ultraviolet–Visible and Fluorescence Spectroscopy 115Rosalind Wolstenholme6.1 Forensic Introduction 1156.2 Theory 1156.2.1 Electronic Transitions 1156.2.2 Photoluminescence and Fluorescence 1186.2.3 Quantification 1206.2.3.1 UV-Vis Quantification 1206.2.3.2 Fluorescence Quantification 1216.3 Instrumentation 1226.3.1 UV-Vis Spectrometers 1226.3.2 Fluorescence Spectrometers/Fluorometers 1236.3.3 Coupling Techniques 1266.3.4 Microspectrophotometers 1266.3.5 Hyperspectral Imaging 1266.3.6 Filtered Light Examination 1276.4 Application to Analyte 1286.4.1 Transmission Analysis in Solution 1286.4.1.1 UV-Vis Solution Analysis 1286.4.1.2 Fluorescent Solution Analysis 1296.4.2 MSP Sample Preparation 1296.4.3 Acquiring a Spectrum 1306.4.3.1 Capture of Spectra in Solution 1306.4.3.2 MSP and HSI Sample Analysis 1316.4.4 Forensic Applications 1316.4.4.1 Writing Ink Examination 1326.4.4.2 Fibre Examination 1336.5 Interpretation and Law 1346.5.1 Interpreting UV-Vis Spectra 1356.5.2 Interpreting Fluorescence Spectra 1376.5.3 UV-Vis and Fluorescence Spectroscopy in Court 1386.6 Case Studies 1386.6.1 Case Study 1 1386.6.2 Case Study 2 1396.7 Forensic Developments 140References 1407 Infrared Spectroscopy 145Barbara Stuart7.1 Introduction 1457.2 Theory of the Technique 1457.2.1 Basis of the Technique 1457.2.2 Instrumentation 1467.2.3 Transmission Spectroscopy 1487.2.4 Reflectance Spectroscopy 1487.2.5 Infrared Microspectroscopy 1507.2.6 Handheld and Portable Instruments 1517.3 Application to Analyte 1517.3.1 Sampling 1517.3.2 Spectrum Analysis 1527.4 Interpretation and Law 1557.5 Case Studies – Discrimination of Acrylic Fibres 1577.6 Forensic Developments 158References 1598 Raman Spectroscopy 161Rosalind Wolstenholme8.1 Forensic Introduction 1618.2 Theory 1618.2.1 Raman Scattering 1618.2.2 Modes of Vibration 1638.2.3 Raman Shift 1658.2.4 Raman Instrumentation 1668.2.4.1 Lasers, Fluorescence, and Resolution 1668.2.4.2 Dispersive versus FT 1678.2.4.3 Dispersive Raman Spectrometers 1688.2.4.4 FT-Raman Spectrometers 1698.2.4.5 Polarisers 1698.2.4.6 Microscopes and Imaging 1698.2.4.7 Portable Instruments and Probes 1708.2.4.8 Quantitation 1708.2.5 Advanced Techniques 1718.2.5.1 Resonance Raman Spectroscopy 1718.2.5.2 SERS/SERRS 1718.2.5.3 SORS 1728.2.6 Advantages and Disadvantages of Raman Spectroscopy 1738.3 Application to Analyte 1748.3.1 Acquiring a Spectrum 1748.3.2 Forensic Applications 1758.3.2.1 Pen Ink 1758.3.2.2 Paint 1758.3.2.3 Drugs of Abuse 1768.4 Interpretation and Law 1778.4.1 Interpreting Raman Spectra 1778.4.2 Raman Spectroscopy in Court 1798.5 Case Studies 1808.5.1 Case Study 1 1808.5.2 Case Study 2 1808.6 Forensic Developments 181References 1819 Scanning Electron Microscopy 185Grzegorz Zadora and Aleksandra Michalska9.1 Introduction 1859.2 Theory of the Technique 1869.2.1 Scanning Electron Microscope 1869.2.2 X-Ray Detection 1919.2.3 Operating Conditions 1929.2.4 Specimen Preparation 1939.2.4.1 Vacuum Evaporation 1949.3 Application to Analyte(s) 1959.3.1 Gunshot Residue 1969.3.2 Glass 2009.3.3 Other Samples 2039.4 Interpretation and Law 2039.4.1 Evidence Evaluation on Source Level 2039.4.2 Evidence Evaluation on Activity Level 2069.5 Case Study 2079.5.1 GSR – Case Study 2079.5.2 Glass – Comparison and Classification Problem 2099.5.3 Glass –Was the Car Bulb Switched on During the Accident? 212References 21410 Mass Spectrometry 219Mark C. Parkin and Alan Brailsford10.1 Introduction 21910.1.1 Forensic Application of Mass Spectrometry 22110.2 Theory of the Technique 22310.2.1 Principles of Mass Spectrometry 22310.2.2 Sample Introduction 22410.2.3 Modes of Sample Ionisation 22510.2.3.1 Electron Ionisation 22510.2.3.2 Chemical Ionisation 22710.2.3.3 Electrospray Ionisation 23010.2.3.4 Atmospheric Pressure Chemical Ionisation 23110.2.3.5 Desorption and Ambient Methods 23210.2.3.6 Matrix-Assisted Laser Desorption/Ionisation 23210.2.3.7 Secondary Ion Mass Spectrometry 23410.2.3.8 Desorption Electrospray Ionisation 23410.2.3.9 Direct Analysis in Real Time 23410.2.4 Ion Separation – Mass Analysers 23510.2.4.1 Mass Range, Resolution and Accuracy 23510.2.4.2 Magnetic Sector 23610.2.4.3 Quadrupoles – Quadrupole Mass Filter 23610.2.4.4 Quadrupole Ion Trap 23710.2.4.5 Time of Flight 23810.2.4.6 Fourier Transform Instruments – Ion Cyclotron Resonance 23910.2.4.7 Fourier Transform Instruments – Orbitrap 24010.2.4.8 Tandem Mass Spectrometry – Ion Fragmentation by Collision Induced Dissociation 24110.2.4.9 Tandem Mass Analysers – Ion Traps 24210.2.4.10 Tandem Mass Analysers – Triple Quadrupoles 24210.2.4.11 Tandem Mass Analysers – Hybrid Instruments 24210.2.5 Ion Detection 24310.2.5.1 Electron Multipliers 24310.2.5.2 Faraday Cup 24410.2.6 Anatomy of a Mass Spectrum 24410.2.6.1 The Molecular or Quasi-Molecular Ion 24510.2.6.2 The Fragment Region 24710.2.6.3 Full Scan Mass Spectra 24710.2.6.4 Product Ion Spectra 24810.2.6.5 Extracted Ion Chromatograms 24810.2.6.6 Selected Ion Chromatograms and Multiple Reaction Monitoring 24910.2.6.7 Precursor Ion Detection and Neutral Loss Scanning 25210.3 Application to Analytes 25210.4 Interpretation and Law 25410.4.1 Chain of Custody 25410.4.2 New Forensic Regulations 25510.4.3 ID Criteria – Screen and Confirmation 25510.4.4 Chromatographic Criteria 25610.4.5 Mass Spectrometric Identification Criteria 25610.5 Case Studies 25710.5.1 Serial Killing by Poisoning 25710.5.2 Surreptitious Insulin Administration 25710.6 Forensic Developments 25810.6.1 Beyond Blood and Urine 25810.6.2 High Mass Accuracy Mass Spectrometry 25910.6.3 Mobile Mass Spectrometers 260References 26111 Isotope Ratio Mass Spectrometry 267Sarah Benson and Kylie Jones11.1 Forensic Introduction 26711.2 Basis of the Technique 26811.2.1 Isotopes 26811.2.2 Isotopic Abundance and Delta Notation 26811.2.3 Standards and Reference Materials 26911.2.4 Isotopic Variability – Fractionation and Mixing 27011.2.5 Isotopic Variability of Natural Materials 27211.2.6 Instrumentation: Stable Isotope Ratio Mass Spectrometers 27211.3 Introduction to the Isotope Ratio Mass Spectrometer 27611.3.1 IRMS – Detection and Measurement 27611.3.2 Sample Preparation 27711.3.3 Bulk Stable Isotope Analysis 27711.3.4 Bulk Measurements by Quantitative High Temperature Combustion 27811.3.5 Bulk Measurements by Quantitative High Temperature Conversion 27911.3.6 Compound Specific Isotope Analysis 27911.4 Interpretation 28011.5 Case Studies 28111.6 Applications in Forensic Science 28311.6.1 Distinguishing between Naturally Occurring and Synthetic Materials in Doping, e.g. Endogenous and Exogenous (Synthetic) Testosterone 28411.6.2 Determining Authenticity and Predicting Geographical Origin of Food, Pharmaceuticals and Other Materials, e.g. Counterfeiting 28411.6.3 Tracing the Geographic Origin and Movement of Wildlife, Persons and Materials 28411.6.4 Identifying the Source of Environmental Contaminants 28511.6.5 Determining the Geographical Origin of Plant Materials, e.g. Natural Illicit Drugs – Cannabis, Cocaine, and Heroin 28511.6.6 Characterising Microorganisms 28611.6.7 Determining Synthetic Pathways Used to Manufacture Illicit Drugs, e.g. Ecstasy and MDMA, Methamphetamine, and Amphetamine 28611.6.8 Distinguishing between Two or More Samples of a Material to Infer Source or a Common Origin 28711.6.9 Distinguishing Between Two or More Samples of Ignitable Liquids and Chemicals 28711.6.10 Determining Source Through Association of Starting Materials and End Products, e.g. Explosives 28811.7 Future of IRMS and Stable Isotopic Comparisons 288References 288Part III Chromatographic Techniques 29512 Chromatographic Separation and Theory 297Sue Jickells and Shari Forbes12.1 Introduction 29712.2 Chromatography 29812.2.1 Planar Chromatography 29912.2.2 Column Chromatography 30012.3 The Separation Process 30012.3.1 Distribution Constant 30312.3.2 Hold-Up Time (or Volume) 30412.3.3 Retention Time (or Volume) 30512.3.3.1 Retention Time and Sample Concentration 30612.3.4 Retention Factor 30612.3.5 Separation Factor 30712.4 Separation Theory 30712.4.1 Plate Theory 30712.4.2 Theory versus Practice: Band Broadening 30812.4.3 Rate Theory 31112.4.3.1 Eddy Diffusion (A) 31212.4.3.2 Longitudinal Diffusion (B) 31312.4.3.3 Mass Transfer (C) 31412.4.3.4 Non-Column Parameters Contributing to Band Broadening 31612.5 Practical Applications of Chromatographic Theory 31612.5.1 Optimising Chromatographic Separations 31712.5.1.1 Resolution 31712.5.1.2 GC 31912.5.1.3 Mobile Phase 32012.6 Conclusion 323References 32313 Gas Chromatography 327Shari Forbes13.1 Introduction 32713.2 Gas Chromatography Components 32713.2.1 Mobile Phase System 32813.2.2 Sample Injection System 32913.2.2.1 Liquid Samples 33013.2.2.2 Gases and Volatile Compounds 33413.2.2.3 Gas Samples 33413.2.2.4 Volatile Compounds: Headspace Analysis 33513.2.2.5 Static Headspace Analysis 33513.2.2.6 Dynamic Headspace Analysis 33613.2.2.7 Pyrolysis GC 33813.2.3 Columns and Chromatographic Separation 33813.2.3.1 Column Selection 34013.2.3.2 Column Temperature and Programming 34113.2.4 Detectors and Detection Systems 34313.2.4.1 Flame Ionisation Detectors 34413.2.4.2 Electron Capture Detectors 34513.2.4.3 Nitrogen–Phosphorous Detectors 34513.2.4.4 Mass Spectrometric Detection Systems 34613.3 Application to Analyte 34813.3.1 Sample Derivatisation 34813.3.2 Qualitative Analysis 35013.3.3 Quantitative Analysis 35113.3.3.1 Methods of Quantitative Analysis 35313.4 Interpretation and Law 35413.5 Case Studies 35613.5.1 Case Study 1 35613.5.2 Case Study 2 35713.6 Forensic Developments 35813.6.1 Multidimensional GC 35813.6.2 Portable GC 361References 36214 High Performance Liquid Chromatography and Ultra-High Performance Liquid Chromatography Including Liquid Chromatography–Mass Spectrometry 365Sophie Turfus and Luke N. Rodda14.1 Introduction 36514.2 Components of an HPLC instrument and their Optimisation 36814.2.1 Pump and Mixer 36814.2.2 Autosampler and Inlet 37014.2.3 Injector 37014.2.4 Column 37014.2.4.1 Stationary Phase 37114.2.4.2 Column Dimensions 37314.2.4.3 Particle Size 37314.2.4.4 Pre-Column/Guard Column 37314.2.5 Fittings 37414.2.6 Mobile Phase 37514.2.6.1 Mobile Phase A 37614.2.6.2 Mobile Phase B 37614.2.7 Effect of Temperature/Flow Rate 37914.2.8 Detector 38014.2.8.1 Mass Spectrometer 38014.2.8.2 UV Detector 38214.2.8.3 PDA Detector 38314.3 Related Techniques 38414.3.1 Ion Chromatography 38414.3.2 Affinity Chromatography 38414.3.3 Chiral Chromatography 38514.4 Chromatography Theory 38514.5 Detection 38614.6 Coupling of Liquid Chromatography to Mass Spectrometry 38814.7 Types of Analytes 39014.7.1 Basic Analytes 39014.7.2 Acidic Analytes 39014.7.3 Proteins 39114.7.4 DNA 39114.7.5 Chiral Compounds 39214.7.6 Bulk Drugs and High-Concentration Analytes 39214.7.7 Low-Concentration Analytes 39214.8 Accreditation and Method Validation 39314.8.1 Use of Internal Standards 39314.8.2 Effect of Sample Matrix 39414.8.3 Ion Ratios 39414.9 Interpretation of Results in the Forensic and Legal Context 39414.10 Case Studies 39614.10.1 Case Study 1: Post-Mortem Death Investigation – Poly-Drug Overdose 39614.10.2 Case Study 2: Post-Mortem Death Investigation – No Derivatisation Needed for LC-MS 39714.10.3 Case Study 3: Driving Under the Influence of Drugs – Increased Sensitivity with LC-MS 39814.11 Forensic Developments 39914.11.1 Column Switching and Two-Dimensional HPLC 39914.11.2 Capillary Liquid Chromatography 40114.11.3 Column-on-a-Chip Technologies 40114.12 Conclusion 402References 40215 Capillary and Microchip Electrophoresis 407Lucas Blanes, Ellen Flávia Moreira Gabriel, Renata Mayumi Saito, Wendell Karlos Tomazelli Coltro, Nerida Cole, Philip Doble, Claude Roux and Robson Oliveira dos Santos15.1 Capillary Electrophoresis: Introduction 40715.2 Microchip-Capillary Electrophoresis 41015.2.1 Sample Injection Modes in ME 41015.3 Detection Systems 41115.4 CE and ME in Forensic Analysis 41215.5 Case Study: Lab-on-a-Chip Screening of Methamphetamine and Pseudoephedrine in Clandestine Laboratory Samples 41215.5.1 Screening of Methamphetamine and Pseudoephedrine from Clandestine Laboratories 41615.5.2 Interferents 41615.5.3 Simulated Surface Swabs 41815.6 Conclusions 418Acknowledgements 419References 419Index 425