This article reports on a project in which a novel extraction device, capillary microextraction of volatiles (CMV), was coupled to a TRIDION-9 GC-MS with a needle trap (NTD) and evaluated for the analysis of ignitable liquids fire debris.
The performance of the TRIDION-9 was compared to a benchtop GC-MS using CMV. A system detection limit of -10 ng for each of 20 key ignitable liquid residue (ILR) compounds was determined for the T9 GC-MS. Dynamic headspace sampling of simulated ILRs was performed in closed and open-air systems Closed-system evaluations of the CMV/NTD technique resulted in extraction performance similar to the CMV alone; however, ILR analysis on the T9 was impacted by limited chromatographic resolution. Compound identification was possible for 14 out of the 20 selected compounds on the T9 when 1 ml of a 1-percent standard accelerant mixture (SAM) was sampled, compared to 17 compounds on the benchtop GC-MS for the same mass loading. No significant differences were found between CMV and CMV/NTD sampling, suggesting that the combined technique does not have affinity bias. Although the potential of the CMV/NTD extraction coupled to a T9 GC-MS for fire debris analysis was limited by the chromatographic resolution of the instrument, this study provides proof of concept for the CMV’s potential for the extraction of ILRs in combination with portable GC-MS systems.