火场润滑油燃烧残留物的SPME-GC/MS检验方法研究

Using SPME-GC/MS to Identify the Lubricating Oil from Combustion Residues Likely Found at the Arson Spot

本文对固相微萃取-气质联用法(SPME-GC/MS)检验火场润滑油燃烧残留物的提取和分析条件进行了研究。对润滑油分析的程序升温作了实验测定;优化了萃取温度、萃取时间、解吸温度和解吸时间四个影响固相微萃取效果的因素;考察了润滑油在不同载体上燃烧前后的组分变化规律。希冀为火场润滑油燃烧残留物的检验提供科学依据。

In this paper, the conditions of extraction and analysis were studied for the SPME-GC/MS to test the lubricating oil with its combustion residue that is likely to be left at the arson spot. The programmable temperature-rising procedure was defined for analysis of the selected lubricating oil. Four factors, of influence upon solid-phase micro-extraction （SPME）, were optimized about the temperature and time for both extraction and desorption. The componential variation was respectively analyzed before and after combustion of the lubricating oil carried by different materials （wood, cotton material, paper and rubber）. It was found that the better conditions for SPME should be set at the 80 ℃ lasting 30 min for extraction and 240℃ keeping 3 min for desorption. The influential order is sequentially from extraction time followed by the extraction temperature to desorption time with the succession of desorption temperature, showing their strength gradually decreasing. The minimum detectable volume of the SPME-GC/MS is about 0.2 μL injection of the lubricating oil because its major components can be measured at this quantity. For residual components combusted with their carriers, their consecutive disappearance one after another begins with the compounds of indan, follows with those of naphthaline at the prior and phenanthrene the posterior, and finally comes those containing nitrogen and/or oxygen. However, the alkane of C24~C26 is still detected even after the lubricating oil completely bums out, thereby making it the characteristic constituent for identification of the lubricating oil. Different carriers tested in this research have no impact for either the combustion or the residues left. Such results obtained above can provide the scientific basis for the analysis of lubricating oil by its combustion residues from arson spot.