Persistence of Polydimethylsiloxane Condom Lubricants

Abstract

Polydimethylsiloxane (PDMS) is commonly used to lubricate condoms. The detection of PDMS on swabs from complainants can be used to support an allegation of sexual assault. Previous research has focused on establishing analytical techniques for detecting PDMS. This research examined the persistence of PDMS on the penis, in the vagina, in the mouth, and on skin. The longest PDMS detection times were 20 h on the penis, 35 h in the vagina, and 52 h on skin. PDMS was detected up to 4 h in the mouth if the participant did not eat or drink and up to 9 h if the participant slept. PDMS was not detected in the mouth after eating or drinking. The presence of biological fluids had no detrimental effect on the analysis. Aqueous extraction of swabs for DNA did not remove any significant amount of PDMS; hence, swab remains could be subsequently analyzed for PDMS.

Adhesion and Mechanical Properties of PDMS-Based Materials Probed with AFM: A Review

“…Because of its optical clearance, PDMS has been used in so called suspended particle devices for smart window applications [14][15][16]. Applications also include, but not limited to defoamers [17], contact lenses [18], waterrepellent coatings [19], cosmetics [20], lubricants [21], and many others. However, in this review we will focus on adhesive and mechanical properties of PDMS.…”

Combined Statistical Analyses of Forensic Evidence in Sexual Assault: A Case Report and Brief Review of the Literature

“…A survey on 841 case reports from three law enforcement agencies in the United States showed that the prevalence rate of condom use in sexual assaults ranged from 11.7 to 15.6% (2). Consequently, since many years, and increasingly lately, Courts have been requesting the examination of the intimate swabs of the victims, seeking for traces of condom lubricants and/or other sexual lubricants (3–6), also because several works showed that the persistence of condom lubricants can be quite significant, up to 52 or 25 h on the skin or in the vagina of the victim, respectively, and up to 20 h on the penis of the assailant (3,7–10). Given the limited number of swabs that may be collected, in certain circumstances, from a complainant during her medical examination, the subsequent decision concerning which swabs to analyze for the presence of DNA versus condom lubricants is pivotal and can heavily impact on the outcome of the case.…”

“…Maynard et al in 2001 analyzed 50 lubricants from condoms and personal lubricant products using a series of instrumental techniques including diffuse reflectance infrared Fourier‐transform spectroscopy (DRIFTS), GC‐MS, liquid chromatography–mass spectrometry (LC‐MS), and pyrolysis–gas chromatography–mass spectrometry (Py‐GC‐MS) (10). Indeed, a common feature of most proposed protocols devised to identify condom‐related compounds is that complementary methods should be also applied (5,7,11).…”

“…Tottey and colleagues investigated the persistence of condom lubricants in the vagina or in other personal orifices after 24 h. Interestingly, they studied the interference brought about by biological fluids on intimate swabs (7).…”

“…As appears from this survey of the literature, most of the published work has been focused on establishing analytical techniques for detecting pristine lubricants, and only sometimes these protocols have been tested on swabs collected from real caseworks. To the knowledge of the authors, only Tottey et al (7) reported on the detection of condom‐related lubricants on the material remaining on intimate swabs after DNA analysis. This issue is quite critical in real caseworks because just a limited number of swabs can be collected from a complainant during medical examination, and priority is primarily given to DNA extraction, for obvious reasons of an increased evidential value associated with genetic information rather than to the presence of lubricants.…”