Analysis of accelerant in fire debris by pyrolysis gas chromatography-mass spectrometry

Abstract

A strategy for the analysis of the accelerant and combustion residues in fires was developed by pyrolysis gas chromatography-mass spectrometry (PyGC-MS). Two kinds of accelerants (gasoline and diesel) and two kinds of carriers (cotton cloth and polyethylene terephthalate (PET) plastic) were selected for this research. Combustion residues of the accelerant and carrier were prepared. The characteristic temperatures of the samples were determined by thermal analysis technology. Then the analysis conditions were optimized and selected. The samples were subjected to PyGC-MS by a stepwise method consisting of flash analysis and pyrolysis analysis. The experimental results showed that the pyrolysates of the original combustion residues of the PET carrier consisted of 35 components, while the pyrolysates of the combustion residues of the PET carrier with gasoline, and ones of the combustion residues of the PET carrier with diesel oil consisted of only 25 components. The types and contents of the pyrolysates were different. The established method could distinguish the self-combustion residue of the carrier from the combustion residue of the accelerant and the same carrier. It was suitable for the analysis of the accelerant from the fire debris, and could determine the presence of the accelerant in the fire field. The method can provide a scientific basis for the judgement of the fire property and fire investigation work.