Volatile organic compounds (VOCs) released by carpets are known to produce background interferences in accelerant identifications in cases of arson. In this study a solid-phase microextraction (SPME) method was optimized and used in combination with gas chromatography-mass spectroscopy (GC-MS) technique to analyze the possible interferences of carpet materials when burned at the presence of commonly used accelerants. The GC column temperature program and SPME conditions were optimized (incubation time 5 min, incubation temperature: 30°C, extraction time: 30 min, extraction temperature: 30°C, and desorption time: 2 min). A 0.1 g sample of a Stain Master Pet Protect Carpet (nylon 6,6 polymer was placed in a 10 mL glass vial with septum screw cap for each experiment. The total ion chromatograms (TIC) of gasoline were compared to those obtained from the carpet, gasoline spiked carpet, burned carpet, and burned gasoline spiked carpet and a Target Compound Chromatogram (TCC) was created for each, with toluene, m-,p-xylene, trimethylbenzene, and indane chosen as gasoline target compounds. All gasoline target compounds were identified in the gasoline spiked samples, and the spiked burned carpet, but only toluene was identified in the carpet sample. However, the total ion chromatogram (TIC) of burned carpet was recognizably different from the spiked burned carpet, and that of the gasoline itself. The pyrolysis compounds of carpet burned with and without gasoline were identified. Similar experiments were performed with kerosene as the accelerant. The chromatograms obtained for burned carpet, carpet burned with gasoline and carpet burned with kerosene were unique and distinguishable. The reproducibility of the chromatographic patterns was also tested.

Investigating the background interferences of carpet substrates in accelerant identification

254th National Meeting (2017)

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