石化系塑膠製品在火災現場高溫裂解產生之烷類、芳香族等化合物常導致火場殘渣縱火劑鑑定之干擾，本研究以4種不同聚對苯二甲酸二乙酯(Poly( ethylene terephthalate), PET)原料為研究對象，以靜態頂空濃縮及氣相層析／質譜儀(GC/MS)方法，探討各種PET粒燃燒前、後與添加不同體積縱火劑後殘渣萃取液對縱火劑鑑定之干擾與影響。實驗結果顯示不同種類PET粒燃燒殘渣萃取液均可檢出toluene、ethylbenzene、p-xylene、styrene、1-ethyl-2-methyl-benzene、biphenyl等成分，由其檢出產物多為芳香族類化合物，依ASTM E 1618-01規定，被視為芳香族類液體干擾產物，防火級的PET燃燒殘渣萃取物，除上述主要成分外，還可檢測出高沸點之含溴芳香族類化合物，這類物質應為燃燒過程中的產物。PET粒添加縱火劑燃燒後，殘渣萃取液汁干擾產物明顯較未添加者少。添加微量縱火劑燃燒殘渣無法檢出縱火劑成分；添加足量縱火劑，以氣相層析質譜法所得結果顯示，縱火劑為主要成分，干擾物明顯減少。

Petroleum-based plastic products could be pyrolyzed into alkanes and aromatics causing difficulty in search for ignitable liquid in fire debris. This study applied passive headspace concentration and GC/MS methods to get information from fire debris produced from four brands of poly (ethylene terephthalate)'s (PET) and from above polymers blended with different amount of gasoline, toluene and octane. The results indicate that toluene、ethylbenzene、p-xylene、styrene、1-ethyl-2-benzene and biphenyl are the major products of extracts from PET fire debris and a suffient quality of ignitable liquid in corporated into PET would suppress the signals in chromatograms given by above PET fire debris extracts. Besides, bromo-aromatics were detected with enough portion from fire debris extracts of fire-protected PET and were created during the ignition process.