U.S. flag

An official website of the United States government, Department of Justice.

NCJRS Virtual Library

The Virtual Library houses over 235,000 criminal justice resources, including all known OJP works.
Click here to search the NCJRS Virtual Library

Comparative Analysis of Lubricants Used for Weapons

NCJ Number
Journal of Forensic Sciences Volume: 46 Issue: 3 Dated: May 2001 Pages: 441-447
P. Jonas Johansson M.Sc.; K.Thomas R. Myhrinder B.Sc.; E. Pernilla Gunnarson M.Sc.; Hans Boren Ph.D.
Date Published
May 2001
7 pages
This study presents a comparative analysis of lubricants used for weapons.
The study analyzed and compared mineral oil-based greases thickened with a metal soap. The greases were first analyzed with Fourier-transform infrared spectroscopy (FT-IR). This analysis differentiates between greases with different main constituents. When two samples could not be differentiated with IR, a more thorough analysis was required. The base oil and the soap were separated. The soap was derivatized and the two components were each analyzed with gas chromatography. The metal ions of the soap were analyzed with scanning electron microscopy with an energy dispersive X-ray detector. By the method presented, grease from a weapon may be differentiated from or proven identical to grease collected from a suspect. The grease did not change with respect to composition when the weapon was fired, so the method may be used in many cases. The study included application of the method to an authentic case. In that case, FT-IR analysis proved that grease from a gun used in a shooting was a perfect match to grease in an opened can of grease found in a store where the suspect was employed. The oils were thereafter analyzed by gas chromatography, which showed that the samples were non-identical. Figures, references