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Comparing the Effects of Weathering and Microbial Degradation on Gasoline Using Principal Components Analysis

NCJ Number
Journal of Forensic Sciences Volume: 57 Issue: 1 Dated: January 2012 Pages: 64-69
Date Published
January 2012
6 pages

This study examined ignitable liquid residues recovered from a fire scene.


Ignitable liquid residues recovered from a fire scene will often show signs of weathering as a result of exposure to the heat of the fire. In addition, when the substrate is rich in organic matter, both weathering and microbial degradation may be observed. In this study, 20 ìL aliquots of fresh gasoline samples were intentionally weathered and also subjected to microbial degradation in potting soil. These samples were then analyzed using a passive adsorption-elution recovery method and gas chromatography/mass spectrometry. Peak areas from compounds of interest were normalized and autoscaled and then subjected to principal components analysis. This analysis showed that while lower boiling compounds are subject to weathering, a different set of compounds are subject to microbial degradation. Of the compounds studied, heptane, octane, toluene, and ethylbenzene were the most vulnerable to both weathering and microbial degradation. In contrast, 1,3,5-trimethylbenzene and 2-ethyltoluene were the most resistant to both phenomena. Published by arrangement with John Wiley & Sons.

Date Published: January 1, 2012