This work, which is an extension of the capillary microextraction of volatiles (CMV) application (M. Torres et al., 2020) reported by the Forensic Technology Center of Excellence, involved the optimization of a field-sampling protocol originally used with solid phase microextraction (SPME), now adapted for use with the CMV.
Following the optimization, researchers at Florida International University extracted ignitable liquid residues (ILRs) from simulated fire debris and analyzed the extracted compounds using a portable GC-MS unit. Qualitative sampling researchers then conducted a controlled structural fire for a preliminary field assessment of the sampling protocol and portable unit. This report describes a fast, easy, and inexpensive method for screening for ILR at an active fire scene. It is a 5-minute sampling/extraction protocol (2-minute equilibration and 3-minute sampling), using the CMV and a sample paper cup as the extraction vessel. Results are obtained within 20 minutes, using the sampling protocol in conjunction with the portable GS10 GC-MS method. Multiple key ILR components are reproducibly detected within a low nanogram range. Ongoing work involves continuing to evaluate the cup as an extraction vessel, including the design of an external attachment to improve the extraction efficiency of less volatile analytes found within heavier ignitable liquids. Additional fieldwork will also be conducted to evaluate the current protocol’s efficacy and determine whether further optimization is needed. 5 figures, 1 table, and 7 references