Detection and Characterization of Gasoline based Polycyclic Aromatic Hydrocarbons on Different Materials by Gas Chromatography-Mass Spectrometry

Abstract

Polycyclic aromatic hydrocarbons (PAHs) profile by gas-chromatography-mass spectrometry were recently used for the identification of sources of contamination in environmental forensic investigations. In present study, an effort is given to utilize gas chromatography-mass spectroscopy to obtain PAHs profile that could help forensic scientist in selection of evidence at the scene of fire. In forensic laboratories, the main evidence received in fire burning cases are fire debris which consists of soil, wood, paper, cloth etc. as a piece of individual evidence or mixture. In fire investigation, the type of material collected from the crime scene affects the investigation hence present study focused on which type of material is more suitable while utilizing a polycyclic aromatic hydrocarbon as a source identifier. Total of nine different materials like paper, cardboard, foam, cloth, metal, hair, soil, meat and wood were selected and these are burned with gasoline in partial burning and complete burning conditions. Debris obtained sonicated at room temperature and concentration of 18 PAHs were determined with gas chromatography-mass spectrometry. Results obtained were analyzed with the Principal Component Analysis (PCA) technique to generate a profile of PAHs. It is concluded that partially burned samples provide more information about the use of ignitable liquid to commit the crime as compared to completely burned samples. The meat, hair, metal and soil material provide more information about the presence of ignitable liquid based on the 18 PAHs concentration profile.