Ecole des Sciences Criminelles, University of Lausanne, Switzerland.
Ecole des Sciences Criminelles, University of Lausanne, Switzerland.
Forensic Sci Int. 2021 Jul;324:110793. doi: 10.1016/j.forsciint.2021.110793. Epub 2021 May 3.
Analysis of condom evidence commonly focusses on the detection of silicone-based lubricants, such as polydimethylsiloxane (PDMS). Although various instruments are used to analyse silicone lubricants, pyrolysis-gas chromatography coupled to mass spectrometry (py-GC-MS) is one of the few instruments that presents immediate applicability to casework. However, considering that this technique detects silicone-based evidence, it is important to evaluate the discrimination potential of the method when applied to various samples. Examination of the variability within a large sample set from an international market is needed to evaluate the most distinguishing compounds likely to be detected in casework. In this study, 70 condoms, personal hygiene products, and lubricants, were analysed using py-GC-MS. Resulting pyrograms were characterised using published spectral databases. Pyrolysates data were extracted and evaluated using multivariate techniques. Qualitative visual inspection of the data, as well as statistical analysis, revealed at least five groups within the dataset. Discrimination was based on four main oligomers, as well as six minor compounds from siloxane degradation. Condom lubricants were found to present a very regular pattern, allowing for the majority of them to be differentiated from personal lubricants.
分析避孕套证据通常集中于检测硅基润滑剂，如聚二甲基硅氧烷（PDMS）。虽然有各种仪器用于分析硅基润滑剂，但热裂解气相色谱-质谱联用（py-GC-MS）是为数不多的适用于实际工作的仪器之一。然而，考虑到该技术检测基于硅的证据，评估该方法应用于各种样品时的区分潜力非常重要。需要对来自国际市场的大量样本进行检验，以评估在实际工作中最有可能检测到的最具区分性的化合物。在这项研究中，使用 py-GC-MS 分析了 70 个避孕套、个人卫生用品和润滑剂。使用已发表的光谱数据库对所得热解图谱进行了特征描述。使用多元技术提取和评估热解产物数据。对数据进行定性的目视检查以及统计分析，揭示了数据集中至少有五个组。区分基于四个主要低聚物，以及硅氧烷降解的六个次要化合物。避孕套润滑剂呈现出非常规则的模式，使得大多数润滑剂能够与个人润滑剂区分开来。
