Analysis of Petroleum Products for Forensic and Environmental Applications

In both forensic and environmental applications, it is often important to identify ignitable liquid (IL) residues, to find a suspect or to clean up an oil spill. The ASTM method is commonly used; the extraction methods vary, but the data collection is the same. The instrument used in the ASTM method is gas chromatography mass spectroscopy (GC-MS), which allows a visual identification of the IL contaminating the sample. In this study, the use of Fourier transform infrared spectrometry (FTIR) was used in conjunction with chemometric analysis. Samples were prepared were to simulate an oil spill in natural waters. Two chemometric analysis methods were used: principal component analysis (PCA) and alternating least squares (ALS) to assist in the identification of the contaminant. The FTIR spectra were hard to visually identify, but when paired with PCA and ALS allowed the identification of gasoline and diesel contamination. The use of ALS and PCA together also allowed the identification of blank samples. The use of FTIR with chemometric analysis was found to faster and more efficient, and an accurate method of analysis, when compared to GC-MS.