火场汽油检验鉴定基质干扰官能团的溯源研究OA北大核心CSTPCD

Matrix interference in inspection and identification of accelerant used in arson has always been a focus and difficulty in the field of forensic science.In this work,to further investigate whether carbon-carbon double bonds were functional groups that caused matrix interference,gas chromatography-mass spectrometry(GC-MS)and pyrolysis gas chromatography-mass spectrometry(Py-GC/MS)were used to qualitatively analyze the combustion/cracking products of styrene butadiene styrene block copolymer(SBS,before hydrogenation)and styrene ethylene butene styrene(SEBS,after hydrogenation saturated butadiene carbon-carbon double bonds)from the perspectives of chemical structure and cracking process,and their interference with gasoline identification.Quantitative analysis was conducted on the interference degree of the two types of materials using the similarity of ion flow chromatography(EICs)extracted from alkylbenzene,indene,and polycyclic aromatic hydrocarbon components and the EICs corresponding to gasoline combustion residues.Both qualitative and quantitative results indicated that SEBS had less interference in gasoline identification.Compared to SBS,the characteristic components such as indene,dimethylindene and dimethylnaphthalene could not be detected in SEBS combustion residues,and the relative content of alkyl benzene,indene,and polycyclic aromatic hydrocarbon characteristic components was significantly reduced,indicating that SEBS had a lower degree of "false positive" interference.After loading gasoline for mixed combustion,a significant difference in the relative peak area ratio of characteristic components could be found between SBS and SEBS residues and gasoline combustion residues,which could easily lead to a"false negative" conclusion.During the cracking process of SEBS,fewer cracking products with double bond structures were produced.The correlation between the carbon-carbon double bond structure and the degree of matrix interference in gasoline identification was verified by combining the differences in SBS and SEBS double bond structures and the differences in cracking products.The research results provided important references for further understanding the functional groups that caused matrix interference in the inspection and identification of fire residue.