Comprehensive Analysis And Application Of Characteristic Components Of Wood Products Combustion Residues

With the development of home decoration,construction and other industries,wood products are used more and more in daily life,and their combustion products have more and more interference to the analysis of combustion-supporting agents at the scene of arson.Therefore,based on the wood as the main research object,using gas chromatography-mass spectrometry（GC-MS）technology,full two-dimensional gas chromatography-mass spectrometry technology（GCx GC-MS）and gas chromatography triple quadrupole tandem mass spectrometry（GC-MS/MS）analysis of samples,inspects wood combustion residue characters and its influence on fire accelerant analysis appraisal,set up a system of comprehensive analysis technique,to provide reliable technical basis for this kind of material evidence identification,improve the accuracy of the appraisal result.12 kinds of selected wood simulation different combustion degree of standard sample preparation,using solid phase micro extraction and solvent extraction method to extraction,using gas chromatography mass spectrometry（GC-MS）technology for analysis,and based on the combustion residue of GC-MS spectra of statistical analysis found that wood contains mass ratio of nuclear m/z=85 alkanes compounds,the compounds of carbon number between C₁₂～C₂₃,this is an important characteristic of wood.Pinene was detected in all 10 kinds of wood products,which is also an important indicator of wood products burning residues.Taking solid wood table body as an example,the influence of wood products on the analysis and identification of gasoline was studied.The alkyl benzene and alkyl naphthalene compounds detected in it had a great influence on the analysis and identification of gasoline.Taking polyurethane bakelwood as an example,the influence of wood products on the analysis and identification of diesel oil was studied.The detected compounds,such as straight paraffin,cycloparaffin,laokiotane,phytane,anthracene and methyl anthracene,interfered greatly on the analysis and identification of diesel oil,and also had a certain influence on the analysis and identification of kerosene.The interference of gasoline,diesel oil and kerosene in wood products was analyzed by GC-MS and further analyzed by GCXGC-MS.Taking polyurethane bakelite as an example,the results show that although there are n-alkanes(C_16-C₂₄)in the same part as the diesel part,different compounds such as C₂-C₅alkylbenzene,alkylnaphthalene,alkylindene and alkylanthracene detected in the diesel part are not detected in the polyurethane bakelite.It can be seen that GC×GC-MS technology can effectively eliminate the interference brought by some materials to GC-MS analysis technology,and has incomparable advantages.The wood products with great interference to gasoline,diesel and kerosene were mixed with other common materials in the fire site,and further analyzed by gas chromatography triple quadrupole tandem mass spectrometry（GC-MS/MS）technology.The results show that the SRM ion flow patterns of C₅alkylbenzene and C₆alkylbenzene in the mixed product 1,which is composed of solid wood table body,air conditioning shell and rubber shoes,are obviously different from those of gasoline.The SRM ion flow diagrams of C₄alkyl benzene,C₅alkyl benzene and C₂alkyl naphthalene of the mixed product 2,which is composed of polyurethane bakellite,plastic wrap and carton,are obviously different from those of diesel oil.The SRM ion flow patterns of C₄alkyl benzene,C₅alkyl benzene and C₂alkyl naphthalene in the mixed product 3 are obviously different from those of kerosene,which are composed of density board ornaments,black plastic bags and quilts.The above can be used as the main criterion to distinguish the material and the combustion accelerator.The polycyclic aromatic hydrocarbons（PAHs）in solid wood table and gasoline were quantitatively analyzed by GC-MS/MS method.The average recoveries of four characteristic compounds（p-xylene,1,2-dimethyl-4-ethylbenzene,naphthalene and 1-methylnaphthalene）ranged from 89.2%to 105.2%with relative standard deviations（RSDs）ranging from 1.79%to3.36%.The correlation coefficient R2 was 0.9954～0.9995,showing a good linear relationship.The actual sample was found to have the same composition as gasoline,but there was a certain difference in content.