Characterization and source identification of an unknown spilled oil using fingerprinting techniques by GC-MS and GC-FID

This article describes a case study in which forensic chemical analyses were conducted to determine the liability for the release of an unknown petroleum product into a river. The source of the spilled oil was identified using gas chromatography with mass spectrometry and flame ionization detection by comparing the chemical fingerprints of aliphatic, aromatic, biomarker, and total petroleum hydrocarbon fractions. The source was further confirmed by determining and comparing the diagnostic ratios of a series of source-specific marker compounds, in particular, isomers of polycyclic aromatic hydrocarbons (PAHs) and alkylated series of PAHs within the same alkylation groups. From the chemical fingerprinting and data interpretation results, the authors concluded that the oil spilled was diesel fuel, that the fuel had been only slightly weathered since its spill, that the suspected diesel was clearly demonstrated to be the source of the spilled oil, and that the spilled diesel was relatively fresh and the period since the spill was no more than several days.