FIAA Training - Forensic Arson Analysis and Process
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Training seminar for Fire Investigators Association of Alberta on arson laboratory analysis and process. Presentation goes through the process of collection and analyzing arson samples for the presence of ignitable liquid residues.
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FIAA Training - Forensic Arson Analysis and Process
- 1. Making chemistry data meaningful Forensic Laboratory Analysis and Process: Chemical Analysis for Ignitable Liquid Residues (ILRs) © 2015 Chemistry Matters Inc. Fire Investigation Association of Alberta “Life of a Fire Investigation” September 24, 2015 Court D. Sandau, PhD, PChem
- 2. 2Forensic Laboratory Analysis and Process Introduction © 2015 Chemistry Matters Inc. o Ignitable Liquids are fuels that are used to initiate the combustion process. o The term Ignitable Liquid includes flammable and combustible liquids, and is used to encompass all potential arson chemical evidence. o Ignitable Liquid Residues (ILRs) may be present in fire debris, and can indicate that a fire was started on purpose. Classes of Flammable and Combustible Liquids as Defined by 29 CFR 1910.106 Flashpoint - the temperature at which a particular organic compound/mixture gives off sufficient vapor to ignite in air.
- 3. Gasoline Chromatogram 3 R T : 6 .0 0 - 1 4 .0 0 6 7 8 9 1 0 1 1 1 2 1 3 1 4 T i m e ( m in ) 0 5 1 0 1 5 2 0 2 5 3 0 3 5 4 0 4 5 5 0 5 5 6 0 6 5 7 0 7 5 8 0 8 5 9 0 9 5 1 0 0 RelativeAbundance N L : 8 .2 8 E 6 m /z = 9 0 .5 0 - 9 1 .5 0 + 1 0 4 . 5 0 - 1 0 5 . 1 1 8 . 5 0 - 1 1 9 . 1 0 5 . 5 0 - 1 0 6 . 1 1 9 . 5 0 - 1 2 0 . 1 3 3 . 5 0 - 1 3 4 . 0 8 0 1 0 0 9 et hylben zene m,p-xy lene o -xylene n-p ropylb enzen e 3-ethyltoluene 4-et hyltolu ene 1,3,5-trimethylbenzene 2-ethyltoluene 1,2,4-trimethylbenzene tr imethy lbenze ne C4-benzene 1,2,4 ,5-tetr amethy l-benz ene 1,2,3 ,5-tetr amethy lbenze ne T h r e e M u s k e t e e r s C a s t l e G r o u p G a n g o f F o u r BP 136o C VP 10 mmHg BP 170o C VP 2.1 mmHg BP 218o C VP 0.065 mmHg Increasing Size, Decreasing Volatility, Decreasing Flashpoint Forensic Laboratory Analysis and Process© 2015 Chemistry Matters Inc.
- 4. 4 Outline © 2015 Chemistry Matters Inc. o Sampling o Sample handling and stability of ILRs o Lab processes - Extraction o Lab processes - Analysis o Matrix Effects o ILR Types o Future of ILR Forensics Forensic Laboratory Analysis and Process
- 5. Forensics Analysis Process • Process from start to finish 5Forensic Laboratory Analysis and Process© 2015 Chemistry Matters Inc.
- 6. 6 The Use of Laboratory Analysis © 2015 Chemistry Matters Inc. o Accelerant Detection Canines (ADCs) possess excellent capability to detect chemicals commonly associated with ILRs. o ADCs exceed field equipment currently available for the detection of chemicals commonly associated with ILRs. o However, the ADC is not as adept at determining whether the chemical is from ILRs or from post- combustion products. Forensic Laboratory Analysis and Process
- 7. Canine Identification o Important for the determination of likely accelerant locations Generalized sensitivity comparisons: K-9 – Part per trillion Human – Parts per billion Lab – Parts per million/billion © 2015 Chemistry Matters Inc. 7Forensic Laboratory Analysis and Process
- 8. 8 ILRs are readily extracted from all types of material. Analysis patterns can be compared regardless of sample type. © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 9. 9 Sampling Vessels © 2015 Chemistry Matters Inc. Taken from: E. Stauffer et al, Handbook of Fire Debris Analysis, 2007. Forensic Laboratory Analysis and Process
- 10. 10 Sampling for ILR analysis © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 11. 11 Sampling © 2015 Chemistry Matters Inc. Taken from: E. Stauffer et al, Handbook of Fire Debris Analysis, 2007. From Stauffer: “Samples that are protected from the fire can better retain ILR than those that are exposed to the fire.” “When considering the origin of the fire, the investigator should not take the most burned part as a sample. If the substrate is charred completely beyond recognition, there is little chance that any ignitable liquid has survived.” Forensic Laboratory Analysis and Process
- 12. Example – Burnt Log Evidence • one case – log used as ignition point • Evidence put in C-Can under plastic wrap for storage • Almost pure gasoline signal even though outside of log was charred Forensic Laboratory Analysis and Process 12 © 2015 Chemistry Matters Inc.
- 13. 13 Sampling © 2015 Chemistry Matters Inc. Loss of ILRs: 1.Consumed in the fire as fuel. 2.Lost by evaporation due to heat. High char samples often do not represent good samples. An example of charred wood sample. Forensic Laboratory Analysis and Process
- 14. 14 Sampling © 2015 Chemistry Matters Inc. Best sampling: 1.ILRs often soak into materials and are preserved. 2.Low char material option presents best opportunity to present ILRs if used. A good example is a baseboard. Forensic Laboratory Analysis and Process
- 15. 15 Sample Handling © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 16. 16 Sampling Vessels Sampling Package •Chain of Custody documentation (CoC) •Pre-cleaned Sample Vessel •Clips and Security tabs •Trip Blanks © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 17. 17 Chain of Custody Documentation A document that lists important information for the fire debris samples. •Demonstration of sample control. •Can be filled out electronically or by hand. •Often misused and represents a weakness in a legal case. •Lawyers love to pick through deficiencies in CoCs. © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 18. 18 Chain of Custody Documentation © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process Signature Signature Filled out to completion - No blanks Arrows look sloppy – fill out form Do not skip lines for sample list Signatures present from sampler, person dropping off samples, and laboratory Date and time on signature line Samples on COC match samples in cooler No empty fields – can be construed as careless
- 19. 19 Chain of Custody Documentation © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process Common issues with COCs •Incomplete fields •No signatures •Arrows instead of filling in •Missing samples/extra samples COCs are a legal document showing transition of samples from field to laboratory Forms need to be filled out properly and completely to demonstrate proficiency and thoroughness.
- 20. 20 Sampling Vessels Preference for unlined heat treated sampling cans. •Ensures highest degree of cleanliness •Ensures consistency • Also heat treated carbon strips used for extraction © 2015 Chemistry Matters Inc. Interferences Target compounds Inc. flashpoint Pre-Treatment Post-Treatment Heat above extraction temperature Forensic Laboratory Analysis and Process
- 21. 21 Sample Integrity Clips and security tabs © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 22. 22 Sample Integrity Secondary containment in evidence bags. -Prevents moisture contacting outside of can -Provides secondary barrier to prevent high ILR containing evidence from contaminating low ILR evidence © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 23. 23 Sample Integrity Trip Blanks •Pre-cleaned sampling cans are taken to the investigation site, and returned to the lab, unopened. •The cans travel with the other samples. •Allows proof that potential cross- contamination during transport did not occur. © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 24. 24 Stability of ILRs © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 25. 25 Chemical properties of ILRs Important properties of chemicals are affected by the matrix… oVolatility oSolubility in water oReaction with light (photolysis) oReaction with other chemicals oFood source for microbes © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 26. 26 Chemical properties of ILRs Example: Gasoline . oOpened gas can – slow evaporation oSpilled at the gas station – fast evaporation oPoured onto log – soaks into wood fibres oPoured onto forest floor – soaks into… binds to organic matter © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 27. 27 Sample Stability ILR can degrade with time. Regulated time between collection of sample and analysis of sample to ensure the sample is representative of the place and time it was collected. Termed “Hold Time” Low concentrations of ILRs allowed to degrade may be undetected in analysis = false negative. © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 28. 28 Sample Stability Regulations also require specific preservation activities. Examples include… Store samples between 2 and 8o C - Inhibits bacterial degradation Store in dark - Photolysis – breakdown chemicals Store samples in correct sample vessel material - Should be inert to the chemicals of interest © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 29. 29 Transfer of Custody to the Laboratory © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 30. 30 Transfer of Custody The CoC is the important document. The receiving person at the lab will check the contents against the CoC. The outer vessel (cooler) will be inspected for integrity, and photographed. Sign-off and formal transfer of custody. © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 31. 31 Sample Extraction © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 32. 32 The Analytical Laboratory There is no clearly defined regulation for the determination of accelerant in a sample. Each laboratory will have its own lab process AND identification process. If a laboratory is not used to dealing with arson samples there could be issues with false positives AND/OR false negatives. © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 33. Sample Extraction 33 Two main analytical routines both use Passive Headspace Concentration. oASTM E1412 – …With Activated Charcoal. oASTM E2154 – …With Solid Phase Microextraction (SPME). Both use moderate heating to enhance the evaporation of ILRs from the sample onto a receiving matrix. Activated charcoal method, the matrix is extracted with a solvent, which is then analyzed for the presence of chemicals associated with ILRs. © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 34. Sample Extraction 34 Equipment: •Can containing fire debris, •Carbon strip – activated and cleaned, •Pin – heat–treated, •Magnet – strong lanthanide magnet. © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 35. Sample Extraction 35 Pin pushed through carbon strip. © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 36. Sample Extraction 36 Magnet used to hold pin to underside of can lid. © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 37. Sample Extraction 37 Can lid reattached with carbon strip hanging above fire debris. © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 38. Sample Extraction 38 The Carbon Strip Volatile organic chemicals (VOCs) adsorb to carbon materials. Selection of high purity, high surface area carbon strips produces a consistent material for extraction. © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 39. Why Carbon? Forensic Laboratory Analysis and Process© 2015 Chemistry Matters Inc. 39 • The carbon strip is comprised of molecular forms of carbon. • These have a strong tendency to bind organic chemicals, such as those in ILRs. planar ring structure
- 40. Pre-Treating Cans/Strips • Cans and carbon strips are pre-heat treated above extraction temperature to remove interferences and potential target compounds Interferences Target compounds Inc. flashpoint Forensic Laboratory Analysis and Process© 2015 Chemistry Matters Inc. 40 Pre-Treatment Pretreatment: Heat above extraction temperature Post-Treatment
- 41. Sample Extraction 41 Batch of prepared cans are placed in an oven, and heated at a set temperature for a set length of time. Temperature Too hot • Pattern of extraction is biased to heavier chemicals. • Preferential extraction of natural chemicals – overloads carbon strip. Too cold • Pattern of extraction is biased to lighter chemicals. • Poor extraction efficiency – reduced capability to detect ILRs. © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 42. Heating a sample • Heating a sample transfers compounds from matrix to headspace of can • Carbon strip then adsorbs compounds • Headspace important – cans should only be ¾ full Forensic Laboratory Analysis and Process Interferences Target compounds Inc. flashpoint © 2015 Chemistry Matters Inc. 42 Heat volatilizes target compounds into headspace Carbon strip adsorbs compounds Heated Can
- 43. Sample Extraction 43 Batch of prepared cans are placed in an oven, and heated at a set temperature for a set length of time. Time Too short • Poor extraction efficiency. Too long • Overloading with natural chemicals. © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 44. Sample Extraction 44 Batch of prepared cans are placed in an oven, and heated at a set temperature for a set length of time. Temperature Too hot • Pattern of extraction is biased to heavier chemicals. • Preferential extraction of natural chemicals – overloads carbon strip. Method Blank Additional empty can prepared and placed in oven. © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 45. Data Analysis 45 © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 46. Lab Process • Laboratory process from start to finish 46Forensic Laboratory Analysis and Process© 2015 Chemistry Matters Inc.
- 47. Data Analysis and Interpretation 47 GC-MS analysis provides a large suite of quantified and semi-quantified chemical data. The forensic analyst can then provide analysis using numerous interpretive tools: •Chemical pattern and group analysis •Statistical tests •Reference comparisons © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 48. Data Analysis and Interpretation 48 GC-MS Raw Data Determine presence of indicator chemicals •GC - Retention time •MS - Mass fragmentation Raw data is then separated into groups •Alkanes •Branched / cyclic alkanes •Benzenes •Naphthalenes •Indanes © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 49. Gasoline Chromatogram Forensic Laboratory Analysis and Process 6 7 8 9 1 0 1 1 1 2 1 3 1 4 T im e ( m i n ) 0 Figure 1 Summed mass chromatogram for weathered diesel, R T : 6 .0 0 - 1 4 .0 0 6 7 8 9 1 0 1 1 1 2 1 3 1 4 T i m e ( m in ) 0 5 1 0 1 5 2 0 2 5 3 0 3 5 4 0 4 5 5 0 5 5 6 0 6 5 7 0 7 5 8 0 8 5 9 0 9 5 1 0 0 RelativeAbundance N L : 8 .2 8 E 6 m /z = 9 0 .5 0 - 9 1 .5 0 + 1 0 4 . 5 0 - 1 0 5 . 5 0 + 1 1 8 . 5 0 - 1 1 9 . 5 0 + m /z = 1 0 5 . 5 0 - 1 0 6 . 5 0 + 1 1 9 . 5 0 - 1 2 0 . 5 0 + 1 3 3 . 5 0 - 1 3 4 . 5 0 M S 0 8 0 1 0 0 9 et hylben zene m,p-xy lene o -xylene n-p ropylb enzen e 3-ethyltoluene 4-et hyltolu ene 1,3,5-trimethylbenzene 2-ethyltoluene 1,2,4-trimethylbenzene tr imethy lbenze ne C4-benzene 1,2,4 ,5-tetr amethy l-benz ene 1,2,3 ,5-tetr amethy lbenze ne T h r e e M u s k e t e e r s C a s t l e G r o u p G a n g o f F o u r Interferences Target compounds Lower flashpoint 49 © 2015 Chemistry Matters Inc. Sample in Detector Column
- 50. 50 Data Analysis and Interpretation • Stauffer 2008, “Fire Debris Analysis” • Detection of specific chemical groups… 1. Alkanes 2. The Three Musketeers 3. The Castle Group 4. The Gang of Four 5. The Twin Towers 6. The Five Fingers 7. Pristane and Phytane 8. Hash and Trash 9. Aromatic Petroleum Profile benzenes naphthalenes ‘branched’ alkanes © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 51. 51 Distinctive Patterns Three Musketeers C2-benzenes Castle Group C3-benzenes © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 52. 52 Distinctive Patterns Gang of Four C4-benzenes © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 53. 53 Distinctive Patterns Twin Towers C1-naphthalenes Five Fingers C2-naphthalenes © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 54. 54 Examples: Part 1 Matrix effects © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 55. 55 Gasoline - No Matrix © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 56. 56 Gravel © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 57. 57 Burnt flooring © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 58. 58 Burnt wood and glass © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 59. 59 Burnt carpet and flooring © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 60. 60 Partly burnt flooring © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 61. 61 Fresh Vegetation © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 62. 62 Fresh Vegetation Pinene Limonene p-cymene secbutyl benzene Lots of natural chemicals, but can still see pattern of gasoline © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 63. 63 Examples: Part 2 IL Types © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 64. 64 Example profile - alkylbenzenes Gasoline Kerosene Diesel © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 65. Overall Output 65 © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 66. Chemical identification Forensic Laboratory Analysis and Process Figure 1 Summed mass chromatogram for weathered diesel, kerosene and gasoline R T : 6 . 0 0 - 1 4 .0 0 6 7 8 9 1 0 1 1 1 2 1 3 1 4 T im e ( m in ) 0 5 1 0 1 5 2 0 2 5 3 0 3 5 4 0 4 5 5 0 5 5 6 0 6 5 7 0 7 5 8 0 8 5 9 0 9 5 1 0 0 RelativeAbundance N L : 8 .2 8 E 6 m /z = 9 0 .5 0 - 9 1 .5 0 + 1 0 4 .5 0 - 1 0 5 . 5 0 + 1 1 8 .5 0 - 1 1 9 . 5 0 + m /z = 1 0 5 .5 0 - 1 0 6 . 5 0 + 1 1 9 .5 0 - 1 2 0 . 5 0 + 1 3 3 .5 0 - 1 3 4 . 5 0 M S 0 8 0 1 0 0 9 et hylben zene m,p-xy lene o -xylene n-p ropylb enzen e 3-ethyltoluene 4-et hyltolu ene 1,3,5-trimethylbenzene 2-ethyltoluene 1,2,4-trimethylbenzene tr imethy lbenze ne C4-benzene 1,2,4 ,5-tetr amethy l-benz ene 1,2,3 ,5-tetr amethy lbenze ne T h r e e M u s k e t e e r s C a s t l e G r o u p G a n g o f F o u r Figure 2 Summed mass chromatogram for regular gasoline Provides highly specific identification of each chemical. 66 © 2015 Chemistry Matters Inc.
- 67. Target group of key chemicals Forensic Laboratory Analysis and Process We use 58 specific chemicals for analysis, plus visual inspection of hundreds of other chemicals. Partial data output 67 © 2015 Chemistry Matters Inc.
- 68. Target group of key chemicals Forensic Laboratory Analysis and Process We use 58 specific chemicals for analysis, plus visual inspection of hundreds of other chemicals. Partial data output 68 © 2015 Chemistry Matters Inc. Good match Poor match Not present
- 69. Pattern matching Forensic Laboratory Analysis and Process A range of specific profiles are produced for interpretation, examples: 69 © 2015 Chemistry Matters Inc. Alkanes Alkylbenzenes Akylindanes Naphthalenes
- 70. Group matching Forensic Laboratory Analysis and Process Specific target chemicals are also investigated. This example focuses on “The Three Musketeers.” 70 © 2015 Chemistry Matters Inc. Clean fingerprint using specific masses. Makes identification easier. Full pattern of all chemicals.
- 71. Group matching Forensic Laboratory Analysis and Process Specific target chemicals are also investigated. This example focuses on “Castle Group.” 71 © 2015 Chemistry Matters Inc. Clean fingerprint using specific masses. Makes identification easier. Full pattern of all chemicals.
- 72. Group matching Forensic Laboratory Analysis and Process Even at very low concentrations and with lots of potential interfering chemicals present, can still see a clean pattern. 72 © 2015 Chemistry Matters Inc. Full pattern of all chemicals. Clean fingerprint using specific masses. Makes identification easier.
- 73. Overall Output Forensic Laboratory Analysis and Process • Each of 58 target chemicals are quantitatively identified, with a ‘similarity match’ to a library example of the chemical measured. • The concentrations of the 58 chemicals are measured. • Patterns of these chemicals and hundreds of other chemicals are inspected. • Ratios of chemicals are used to distinguish potential interferences and potential contamination, as well as identify IL type. 73 © 2015 Chemistry Matters Inc.
- 74. Data Interpretation Outcomes 74 o Level 1. Determine the presence or absence of an ILR in a sample of fire debris. o Level 2. Distinguish the type of Ignitable Liquid. Classification can be an important aid for fire scene investigators. o Level 3. Commonality - Statistical tests can determine if a group of samples present the same origin of ignitable liquid. o Level 4. If potential source fuels are presented for analysis, advanced chemical analysis and data interpretation can determine a potential IL source. © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 75. Future of Forensic Analysis of ILRs 75 © 2015 Chemistry Matters Inc. Forensic Laboratory Analysis and Process
- 76. Local Supply of Diesel Fuel Forensic Laboratory Analysis and Process© 2015 Chemistry Matters Inc. 76
- 77. Forensic Laboratory Analysis and Process© 2015 Chemistry Matters Inc. 77 Local Supply of Diesel Fuel
- 78. Diesel 2 Diesel 1 78 © 2015 Chemistry Matters Inc.
- 79. Comparison of Gasolines Gas Station 1 Gas Station 2 Forensic Laboratory Analysis and Process© 2015 Chemistry Matters Inc. 79 Hundreds to thousands of compounds in gasoline
- 80. 2D-GC Chromatogram • Benzene • Toluene • C2-benzenes • C3-benzenes • C4-benzenes • C5-benzenes Total of 68 individual compounds used • C1-Naphthalenes • Indanes (throughout) 6th Multidimensional Chromatography Workshop Jan 6 & 7, 2015 Forensic Laboratory Analysis and Process 80 © 2015 Chemistry Matters Inc.
Notes de l'éditeur
- All of these examples are gasoline