As a continuous effort to validate lubricant analysis, this reported study demonstrated how relatively similar products are distinguishable when chemometric techniques are applied to the data obtained through Raman spectroscopy.
Screening for sexual lubricants as a form of trace evidence is a relatively new methodology in forensic science. With increase of condom use in sexual assault cases, sexual lubricant analyses can prove resourceful. Research has provided confidence with the identification of trace lubricants and further classification based on their chemical constituents using direct analysis in real time–mass spectrometry, gas chromatography–mass spectrometry, and Fourier transform infrared spectroscopy. Statistical analyses coupled with these analytical methods have successfully classified lubricant types based on major components and even further, minor additives such as flavors and anesthetics. In the current study, 50 sexual lubricants – 21 personal hygiene products, 12 bottled lubricants, and 17 condoms – were analyzed using Raman spectroscopy and subsequently classified using statistical tools (i.e., principal component analysis, hierarchical cluster analysis and linear discriminant analysis). The evaluation of two classification models yielded a classification accuracy rate of 95.56 percent and 98.57 percent for the neat and DCM/MeOH solvent models, respectively, using linear discriminant analysis as a supervised classification method. (publisher abstract modified)