Lubricant Analysis

Contributed by Jeffrey Dake

Condom lubricants, commercial sexual lubricants and improvised lubricants may be of evidentiary value in criminal casework, particularly in sexual assault cases. Residues from these products may be found and collected from bodily swabs (vaginal, penile, etc.), intimate items of the involved parties, and/or bedding. The materials found in these residues can be compared to the composition of condom lubricants and/or sexual lubricants suspected to have been used to facilitate a sexual act. Condom lubricants and sexual lubricants typically consist of base lubricants, which may be water soluble or water insoluble in nature. Additionally, these types of products may contain additives in order to achieve a functional end (such as the addition of a spermicide, a flavoring, or a desensitizing agent), to act as a preservative, or as a by-product of the manufacturing process. A variety of instrumental techniques may be employed in the analysis of lubricant materials including, but not limited to microscopy, Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry.

The presence or absence of materials associated with lubricants may help to corroborate or refute a party’s account of the events. Additionally, as condoms are a barrier method for preventing pregnancy and the transmission of sexually transmitted diseases, their use in a sexual assault may prevent the transfer of DNA evidence. As such, the presence of materials associated with condom residues may be the most probative evidence in these types of offenses.

Additional References:

1. Blackledge, R. D., Vincenti, M., “Identification of Polydimethylsiloxane Lubricant Traces from Latex Condoms in Cases of Sexual Assault”, JFSS, 34 (4), PP. 245-256, 1994.

2. P. Maynard, K. Allwell , C. Roux, M. Dawson, D. Royds, “A Protocol for the Forensic Analysis of Condom and Personal Lubricants Found in Sexual Assault Cases”, FSI, 124 (2001), PP. 140-156.

3. Keil, Wolfgang, “Condom Trace Evidence in Sexual Assaults: Recovery and Characterization”, Forensic Analysis on the Cutting Edge, Edited by Blackledge, John Wiley and Sons, 2007. PP. 81-111.

4. G.P. Campbell, A.L. Gordon, “Analysis of Condom Lubricants for Forensic Casework”, J. Forensic Sci., Vol. 52, No. 3, May 2007, PP. 630-642.