Profiling ignitable liquid residues (ILRs) and potential interfering compounds during arson and arsonous wildfire investigations - 8th Multidimensional Chromatography Workshop 2017
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During the 8th Multidimensional Chromatography Workshop 2017 in Toronto, Ontario, Dr. Court Sandau presented on profiling ignitable liquid residues (ILRs) and potential interfering compounds during arson and arsonous wildfire investigations.
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Profiling ignitable liquid residues (ILRs) and potential interfering compounds during arson and arsonous wildfire investigations - 8th Multidimensional Chromatography Workshop 2017
- 1. Profiling ignitable liquid residues (ILRs) and potential interfering compounds during arson and arsonous wildfire investigations January 8 & 9, 2017 8th Multidimensional Chromatography Workshop Court Sandau, PhD
- 2. 2© 2016 Chemistry Matters Inc. Copyright Statement All rights reserved. No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of Chemistry Matters Inc.
- 3. Collaborators • Phil Richards, Lisa Kates, and Lacey Harbicht - Chemistry Matters Inc. • James Harynuk and Paulina de la Mata - University of Alberta • Frank Dorman - Penn State University 3© 2016 Chemistry Matters Inc.
- 4. 4 8th Multidimensional Chromatography Workshop Jan 8 & 9, 2017
- 5. How complicated can it get? ++ = Thousands of Compounds 5© 2016 Chemistry Matters Inc.
- 6. “GCxGC–TOFMS offers an extremely promising future in the field of fire debris analysis. It permits better separation, and, therefore, better specificity of the analysis of ILR. This will be the change of technique that will lead to a significant improvement of the analysis of fire debris samples in the future.” 6 Stauffer, E., Newman, R., Dolan, JA Handbook Fire Debris Analysis (2007) 8th Multidimensional Chromatography Workshop Jan 8 & 9, 2017
- 7. 7 Sample extracts GC Analysis Standard Interpretation Detection Type 2D-GC Analysis Statistical Analysis Detection Type Sources History Interferences 8th Multidimensional Chromatography Workshop Jan 8 & 9, 2017
- 8. The Process of Sampling and Analysis 8© 2016 Chemistry Matters Inc.
- 9. 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 9© 2016 Chemistry Matters Inc. • Routine analysis looks at compound presence/absence and relative abundance using SIM focused on benzenes
- 10. Distinctive Patterns Three Musketeers C2-benzenes Castle Group C3-benzenes 10© 2016 Chemistry Matters Inc. Gang of Four C4-benzenes Twin Towers C1-naphthalenes Five Fingers C2-naphthalenes
- 11. ILR Identification in Arson Samples • Use targeted GC-MS analysis of 63 marker compounds • Developed based on experience, standard availability and presence in accelerants • Is 63 compounds enough to fingerprint ILR source in samples with potential interferences? 11© 2016 Chemistry Matters Inc.
- 12. Problem: Matrix effects 12© 2016 Chemistry Matters Inc.
- 13. Burnt baseboardsChar debris Burnt Flooring Control Flooring Soil and humusForest debris ILRs are readily extracted from all types of material. Analysis patterns can be compared irrespective of sample type. 13© 2016 Chemistry Matters Inc.
- 14. Gasoline - No Matrix 14© 2016 Chemistry Matters Inc. Three Musketeers C2-benzenes Castle Group C3-benzenes Gang of Four C4-benzenes
- 15. Burnt carpet and flooring 15© 2016 Chemistry Matters Inc.
- 16. Fresh Vegetation Pinene Limonene 4-isopropyl toluene secbutyl benzene Lots of natural chemicals, but can still see pattern of gasoline 16© 2016 Chemistry Matters Inc.
- 17. ILR Analysis on Arsonous Wildfires • ILR confirmation and identification is hardest for soil/vegetation samples due to natural interferences • Conclusion: – Need clean up of extracts to remove interferences (may have very limited improvement) – Need better chromatography 17© 2016 Chemistry Matters Inc. 2D-GC?
- 18. Is 2D better than 1D? Castle Group Benzene, propyl Benzene, 1,3,5-trimethyl Toluene, 2- ethyl Toluene, 4-ethyl Toluene, 3-ethyl Benzene, 1,2,4-trimethyl Benzene, tert-butyl Benzene, isobutyl Benzene, sec-butyl Benzene, 1,2,3-trimethyl 18© 2016 Chemistry Matters Inc.
- 19. Is 2D better than 1D? Group of 4 (i.e. 7) 19© 2016 Chemistry Matters Inc.
- 20. 2D-GC TOF Analysis of ILR • Sample from fire investigation analyzed by 2D-GC • 200-1700 compounds identified in ILR samples 20© 2016 Chemistry Matters Inc.
- 21. 2D-GC Chromatogram • Benzene • Toluene • C2-benzenes • C3-benzenes • C4-benzenes • C5-benzenes Total of 63 individual compounds used • C1-Naphthalenes • Indanes (throughout) 21© 2016 Chemistry Matters Inc.
- 22. Arsonous Wildfire Investigations • Positive results for ILR (based on 1D- GC-MS) in vegetation samples (n=78) were analyzed by 2D-GC-MS • Used targeted analysis on 63 selected compounds • Used percentage mass spectral match to standards or library (>70%) for confirmation of presence/absence of targeted compound – Provides secondary confirmation of presence / absence of targeted compounds 22© 2016 Chemistry Matters Inc.
- 23. 2D vs. 1D – 70%+ Mass Spectral Match (n=78 fire debris samples +ve of ILR) 23© 2016 Chemistry Matters Inc.
- 24. 2D-GC ILR Analysis on Arsonous Wildfires • Conclusion: – 2D-GC provides better chromatographic resolution for ILR targeted compound analysis • Can 2D-GC ILR Targeted Analysis Provide Fingerprinting of Source of Gasoline? 24© 2016 Chemistry Matters Inc. The Experiment:
- 25. Fingerprinting Experiment • Collected 23 gasoline samples • Analyzed (neat) by PONA analysis and conducted statistical analysis – Used as the gold standard • Analyzed (neat) by 2D-GC - Targeted ILR analysis • Added matrix and spiked gasoline to woodchips and analyzed by 2D- GC - Targeted ILR analysis 25© 2016 Chemistry Matters Inc.
- 26. PONA GC-MS Analysis - Gasoline • 652 compounds reported in PONA results • Removed compounds with missing values • Substituted ½ DL for non-detects • 349 compounds used in PCA/HCA 26© 2016 Chemistry Matters Inc. Paraffins/Isoparaffins Olefins Naphthenes Aliphatics
- 27. Multivariate Statistical Analysis of PONA Results 27© 2016 Chemistry Matters Inc.
- 28. 2D-GC-TOFMS Analysis - Gasoline • 63 compounds analyzed in neat gasoline samples (target list) • Removed compounds with zeros for more than 50% of the samples • Substituted ½ detection limit for samples with non detects • 55 compounds remained and used in PCA and HCA 28© 2016 Chemistry Matters Inc.
- 29. 2D-GC-TOFMS Analysis - Gasoline 29© 2016 Chemistry Matters Inc.
- 30. Conclusions for Neat Gasoline Analysis • With PONA analysis, can easily distinguish different sources of gasoline • With targeted 2D-GCTOF analysis, can distinguish sources of gasoline – Maybe not the same resolution as with PONA • What about when matrix is added? – Woodchips 30© 2016 Chemistry Matters Inc.
- 31. 2D-GC-TOFMS Analysis - Fuel Added to Wood Chips • 64 compounds analyzed • Removed compounds with zeros for more than 50% of the samples • 48 compounds remaining • PCA and HCA completed 31© 2016 Chemistry Matters Inc.
- 32. 2D Wood Chips ANALYSIS 32© 2016 Chemistry Matters Inc.
- 33. Conclusions • For successful identification of sources of gasoline during arson investigations, need MORE data • True untargeted analysis may provide enough compounds to distinguish between sources of gasoline in fire debris samples – Determining the source will aid investigators to find those responsible 33© 2016 Chemistry Matters Inc.
- 34. 34 Thank You Contact Info: Chemistry Matters Inc. Court Sandau Cell: 403.669.8566 URL: chemistry-matters.com Twitter: @Chem_Matters LinkedIn: ca.linkedin.com/in/courtsandau Slideshare: www.slideshare.net/csandau