Factors Affecting the Forensic Examination of Automotive Lubricating Oils

• NCJ Number: 234666
• Journal: Journal of Forensic Sciences Volume: 56 Issue: 3 Dated: May 2011 Pages: 741-753
• Author(s): Ryan Hibbard, M.S.F.S.; John V. Goodpastor, Ph.D.; Michelle R. Evans, M.S.F.S.
• Date Published: May 2011
• Length: 13 pages
• Publication Format: Article
• Publication Type: Report (Study/Research)
• Language: English
• Country: United States of America
• Note: Presented in part at the 61st Annual Meeting of the American Academy of Forensic Sciences, February 15–21, 2009, in Denver, CO.

Annotation

This paper examines factors that can affect the analysis of lubricating oils.

Abstract

Lubricating oil comparisons impact a variety of forensic investigations, including cases where oil was transferred from a suspect vehicle to the crime scene or victim. In this study, high-temperature gas chromatography/mass spectrometry was used to examine the influence of oil mixtures and oil changes over time on the comparison of known and questioned lubricating oils. Varying concentrations of oil mixtures were prepared and showed the potential for identifying individual components. Motor oils from 18 automobiles monitored over a 2-month period did not demonstrate significant changes in the chromatographic data. Chemometric analysis of motor oil mass spectral data provided little information regarding differentiation of, or changes in, the samples. Power steering fluid (PSF) from a naturally occurring leak collected from several locations was consistent with the PSF in the automobile's reservoir, and the PSF composition did not change over time. (Published Abstract)