Traces of polymethylsiloxane in case histories of rape: Technique for detection

A number of case histories were recently brought to our attention which were intriguing professionally, yet presented difficulties in proving positive results: reported rape by an agressor wearing a condom. We undertook an indepth analysis of the chemical components of condoms and selected the lubricant for further study. In chemical terms, the silicone oil used, polymethylsiloxane, is clear, colorless and odorless. In this paper, we describe a technique for the detection of polymethylsiloxane. Given that the quantities of lubricant available, in vivo, were likely to be extremely small, we opted to use H-1-NMR. Our results confirm the range for identifying polymethylsiloxane as between 0.0426-0.0440 ppm and two individual case histories gave figures of 0.0424 ppm and 0.0420 ppm. Further studies are underway on the length of time polymethylsiloxane remains on the victim or clothing and on different detection techniques.