REFERENCE: Lee GSH, Brinch KM, Kannangara K, Dawson M, Wilson MA. A methodology based on NMR spectroscopy for the forensic analysis of condoms. J Forensic Sci 2001;46(4): 808–821. ABSTRACT: Both solution and solid state Nuclear Magnetic Res- onance (NMR) spectroscopic techniques have been used to deter- mine differences in commercially available condoms. Whilst solid state NMR is useful for determining the polymer backbone, it is not useful for forensic analysis due to the commonality of the latex con- dom. However solution NMR spectra obtained following a simple extraction procedure using hexane, provides a fingerprint of the ad- ditives in the lubricants. Following the development of a flow chart, basing decisions on the presence of particular peaks present in the solution spectra, 33 of 38 condoms could be individualized. Sam- ples were also analyzed after having the lubricant manually re- moved and soaking the condom in water for 3 to 24 h. These exper- iments were performed to simulate a case of the sample having been used and disposed of by flushing down the toilet, as may be experi- enced in a case of a sexual assault. The results indicated that the only significant water soluble component was polyethylene glycol. The overall results suggest that the method developed may be a quick and useful technique in characterizing condoms. The infor- mation obtained can be used to provide associative evidence be- tween suspect and crime, and so be useful in sexual assault cases. KEYWORDS: forensic science, condom, polydimethylsiloxane, PDMS, polyethylene glycol, PEG, nonoxynol-9, nuclear magnetic resonance, NMR, identification systems The recovery and identification of lubricant and spermicide traces associated with condom use can provide important evidence in sexual assault cases. As the number of cases involving condoms is on the rise, researchers have begun to explore different analyti- cal techniques for their ability to detect the presence of lubricants and spermicides. Previous work has focused on the lubricant poly- dimethylsiloxane (PDMS) extracted from samples taken from vic- tims to confirm the use of condoms (1–5). Infrared (IR) spec- troscopy was the main analytical technique used in the majority of these studies, however chromatographic, mass spectrometric (2) and NMR spectroscopic (4) methods have also been used. There has also been some infrared and mass spectrometric work on the identification of traces of the nonoxynol-9 spermicide (2,6). These methods have been successful in providing evidence that a condom was used in the crime, however they do not provide associative ev- idence, which can link a suspect to that particular crime. Hence a method which is capable of differentiating between lubricants orig- inating from different condom manufacturers or even different in- dividual brands is still in demand. At present it appears that no such technique exists, however Blackledge and Vincenti (2) have sug- gested that gel permeation chromatography may be able to distin- guish between PDMS used in different condom brands. Blackledge has also employed two other methods, 29 Si NMR and Fourier trans- form infrared (FTIR) spectroscopy with Fourier self-deconvolution (FSD), to investigate the siloxane chain length of different PDMS samples. While 29 Si NMR was found not to be sensitive enough, FTIR with FSD showed some ability to discriminate (2). Some de- gree of discrimination has been achieved by the identification of a number of insoluble particles such as talc, silica, and cornstarch by light microscopy and scanning electron microscopy/energy disper- sive X-ray spectroscopy (7,8). In an attempt to find a technique that could distinguish between different brands of condoms, it was decided to study all the soluble organic components that make up the lubricant of the condom, by 1 H NMR as opposed to just the PDMS base (9). The lubricant for- mulation from different manufacturers should differ due to propri- etary product information and thus should afford different 1 H NMR spectra. Moreover, a study of the actual condom sheaths by solid state 13 C NMR was also performed. NMR was chosen as it has been shown to be one of the most suitable methods for the analysis of mixtures of general unknown content. Besides being quantita- tive and highly sensitive (10,11), with just one experiment NMR provides a complete “picture” or fingerprint of all the soluble or- ganic components present in the sample. As these organic molecules are likely to be the lubricant trace evidence left after a sexual assault, the NMR spectrum provides the examiner with a “fingerprint” of the condom used in the assault. Components of Condoms The vast majority of condoms are made from thin latex rubber. Latex is a natural elastomer with the chemical structure cis-1,4- polyisoprene (see insert, Fig. 2). During manufacture the liquid la- tex is vulcanized. This process crosslinks the chain-like rubber molecules to form an elastic network, with sulfur being the pre- dominant vulcanizing agent (12). Condoms are also manufactured from other materials, primarily synthetic polymers and sheep cae- cum (13). At the time of this investigation, polyurethane was the only synthetic material used in commercially available condoms (13). 808 Garry S. H. Lee, 1 Ph.D.; Kari M. Brinch, 2 BSc.; Kamali Kannangara, 2 Ph.D.; Michael Dawson, 2 Ph.D.; and Michael A. Wilson, 2 D.Sc. A Methodology Based on NMR Spectroscopy for the Forensic Analysis of Condoms* 1 Present address: Department of Chemistry, University of St. Andrews, St. Andrews, Fife, KY16 9ST, Scotland. 2 Department of Chemistry, Materials and Forensic Science, University of Technology, Sydney, PO Box 123, Broadway NSW 2007, Australia. * This work was presented at the 15th International Symposium of Forensic Science, Gold Coast, Australia, 2000, 5–10 Mar. 2000. Received 20 March 2000; and in revised form 1 August 2000; accepted 1 Au- gust 2000. Copyright © 2001 by ASTM International