Ecole Des Sciences Criminelles, University of Lausanne, Switzerland.
Ecole Des Sciences Criminelles, University of Lausanne, Switzerland.
Forensic Sci Int. 2020 Dec;317:110513. doi: 10.1016/j.forsciint.2020.110513. Epub 2020 Sep 20.
Analysis of condom evidence commonly focusses on the detection of silicone-based lubricants, such as polydimethylsiloxane. However, water-based compounds such as propylene glycol or glycerin can also be used as condom lubricants and may, therefore, be detected as transferred traces. Evaluation of the variability amongst a large sample set from an international market is needed to determine what are the most likely compounds that may be detected in casework. In this study, 165 condoms, personal hygiene products, lubricants, creams and oils were analysed using gas-chromatography coupled to a mass spectrometer detector (GCMS). The resulting compounds were identified using mass spectral databases, then the data were extracted and evaluated using established multivariate statistical techniques, such as principal component analysis and discriminant analysis. Qualitative visual inspection, as well as statistical analysis, revealed at least twelve different groupings within the dataset. Discrimination was based on variations in the concentration of major compounds, as well as the presence or absence of minor compounds, such as anaesthetics. For the 127 condoms examined, 2 were exclusively water-based lubricated (1.5 %) and 6 contained silicone and water-based components (4.7 %). All the others were only silicone-based (119 condoms, 93.7 %). Strong variation was observed between the different sources of products. Personal hygiene products (PHP), creams, lubricating oils, personal lubricants, and condoms were found to have different chemical compositions. Hence GCMS can be used to assist in the differentiation of water-based residues for investigative purposes.
分析避孕套证据通常集中在检测硅基润滑剂，如聚二甲基硅氧烷。然而，水基化合物，如丙二醇或甘油也可用作避孕套润滑剂，因此可能会被检测为转移痕迹。需要对来自国际市场的大样本进行评估，以确定在实际工作中最有可能检测到的化合物。在这项研究中，使用气相色谱-质谱联用仪（GCMS）对 165 个避孕套、个人卫生用品、润滑剂、乳膏和油进行了分析。使用质谱数据库对所得化合物进行了鉴定，然后使用主成分分析和判别分析等已建立的多元统计技术提取和评估数据。定性目视检查以及统计分析揭示了数据集内至少有十二个不同的分组。区分基于主要化合物浓度的变化，以及次要化合物（如麻醉剂）的存在与否。在所检查的 127 个避孕套中，有 2 个是专门用水基润滑剂润滑的（1.5%），有 6 个含有硅基和水基成分（4.7%）。其他所有避孕套均为纯硅基（119 个，93.7%）。不同产品来源之间观察到强烈的变化。个人卫生用品（PHP）、乳膏、润滑油、人体润滑剂和避孕套被发现具有不同的化学成分。因此，GCMS 可用于协助区分水基残留物，以进行调查目的。
