Extraction of Ignitable Liquid Residues by Dynamic Capillary Headspace Sampling and Comparison to the Carbon Strip Method (Final Research Report)

Published

December 1, 2024

Author(s)

Christopher Suiter, Kavita Jeerage

Abstract

The primary goal for this project was to assess the value of an alternative headspace concentration method for the extraction of ignitable liquids (IL) related to fire debris. Headspace methods provide clean samples for analytical analysis, do not require direct contact with potentially dangerous artifacts, are non-invasive, and can be non-destructive. Dynamic vapor microextraction (DVME) is a small-volume purge and trap method that concentrates vapor phase analytes onto a short (1 m to 3 m) section of porous layer open tubular (PLOT) capillary coated with an adsorbent material. DVME has been successfully applied to the analysis of explosives (Lovestead & Bruno, 2010), grave soil (Lovestead & Bruno, 2011), and fuels (Burger et al., 2016a, Harries et al., 2021a) in the laboratory, and has been used to extract volatile compounds from a simulated shipping container in the field (Harries et al., 2019). To evaluate debris from structural fires for IL residue, forensic laboratories in the United States typically utilize passive headspace concentration onto activated carbon strips (ACSs) (ASTM E1412-16), followed by solvent elution and analysis. The high affinity of ACSs for hydrocarbons requires the use of carbon disulfide, a dangerous neurotoxic solvent, to recover the IL compounds. By contrast, DVME can recover characteristic IL compounds from laboratory-generated fire debris with a relatively benign solvent: acetone (Nichols et al., 2014). However, preliminary experiments were conducted with a small quantity of debris in crimp cap vials (the debris had to be pulverized prior to adding to the container) and employed instrument settings that would be unreasonable for the analysis of authentic fire debris (e.g., oven temperatures above 100 oC). This project will investigate whether DVME has potential as a practical alternative for fire debris analysis and lay the necessary groundwork for future validation, standardization, and implementation in forensic practice. In addition, the project aims to improve our understanding of some basic properties of the adsorbent materials important in IL extraction and fire debris analysis, including rates of adsorption and competitive effects.

Citation

National Institute of Justice Publications Listing

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https://nij.ojp.gov/library/publications/list

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Suiter, C. and Jeerage, K. (2024), Extraction of Ignitable Liquid Residues by Dynamic Capillary Headspace Sampling and Comparison to the Carbon Strip Method (Final Research Report), National Institute of Justice Publications Listing, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=958736, https://nij.ojp.gov/library/publications/list (Accessed September 14, 2025)