利用塑料燃烧后形成空腔结构检测汽油燃烧残留物  

Utilization of Combustion-resultant Plastic Cavity to Detect Encapsulated Gasoline Residues:Case Report

作　　者：郑继利 刘占芳[1] 朱军[1] 周正 李光耀 郭洪玲[1] ZHENG Jili;LIU Zhanfang;ZHU Jun;ZHOU Zheng;LI Guangyao;GUO Hongling(Institute of Forensic Science,Ministry of public Security,Beijing 100038,China)

机构地区：[1]公安部物证鉴定中心,北京100038

出　　处：《刑事技术》2021年第5期542-546,共5页Forensic Science and Technology

基　　金：国家重点研发计划(2017YFC0803804);公安部技术研究面上项目(2016JSYJB09)。

摘　　要：目的探讨纵火案件中保存时间较长、易形成密闭空腔结构的塑料类检材汽油燃烧残留物成分的检验方法。方法利用塑料物证燃烧后形成的空腔结构对汽油残留物的密封作用,对检材内的空腔结构进行切割,采用固相微萃取气相色谱-质谱(SPME-GC-MS)方法对检材进行汽油残留物检验。结果检材中检出芳香烃类化合物、直链烷烃、环烷烃等成分,使用SPME-GC-MS方法的检出量更大,结果更符合汽油燃烧残留物的分布规律。结论火场中某些塑料检材经过高温作用,易形成相对密闭的空腔结构,富集大量燃烧时产生的残留物,能够较好地反映火场燃烧时的情况,通过适当的样品前处理可释放空腔内的燃烧残留物,有助于汽油等助燃剂成分的分析检测。Objective To probe into an approach of detecting those burned gasoline residues that were encapsulated inside a cavity of plastic(often kept and stored for long time until examination)that had been undergone with combustion from arson case.Methods For the evidential plastic material that was found of cavity suspected to seal gasoline residues,the cavity was cut open and immediately collected of its retaining substances with solid phase micro-extraction(SPME).The gas chromatography-mass spectrometry(GC-MS)was adopted to detect the collected substances.Results From the collected sample were detected aromatic hydrocarbon compounds,linear alkanes,cycloalkanes and other components.Compared to the adsorption-desorption-GC/MS,the SPME-GC/MS choice showed both a larger detection amount and better result that was more consistent with the distribution of combusted gasoline residues.Conclusion For fire scene where plastic was among the evidential materials,the closed cavity should be scrutinized from the combusted plastic because it is very likely of enriching a large amount of gas components from combustion residues,which can better indicate the burning situation of the fire scene and be extracted through proper sample pretreatment.The cavity-closed gas can help to detect the components of combustion accelerants(e.g.,gasoline in the case here)with an appropriate detection choice(SPME-GC/MS here).

关 键 词：纵火案件 空腔结构 固相微萃取气相色谱-质谱技术 助燃剂 汽油 燃烧残留物 

分 类 号：DF794.3[政治法律—诉讼法学]