安全套遗留微量物证分析研究进展.pdf

第 32 卷，第7 期2023 年7 月化学分析计量CHEMICAL ANALYSIS AND METERAGEVol.32,No.7Jul.2023安全套遗留微量物证分析研究进展陈麒全（中国刑事警察学院法化学系，沈阳110035）摘要安全套证据的分析通常集中于检测避孕套表面的硅基润滑剂，如聚二甲基硅氧烷（PDMS），以及少量其它润滑剂如甘油，丙二醇等，有时还会对安全套上的其它功能成分聚乙二醇（PEG）、壬苯醇醚-9等和固体颗粒进行检验。从样品制备、显微镜分析、光谱分析、色谱分析、质谱分析五个方面概述了PDMS、PEG和壬苯醇醚-9等物质的有效检测方法。光学显微镜和扫描电镜通常用于分析避孕套表面的固体颗粒；傅里叶变换红外光谱则用于分析PDMS和PEG，其可以识别样品吸收峰的相对丰度，但缺乏具体的识别能力，主要用作筛选方法；拉曼光谱主要用于分析PDMS、PEG、壬苯醇醚-9；核磁共振可以用于分析PDMS、PEG、壬苯醇醚-9，具有很高的灵敏度和区分能力；气相色谱-质谱（GC-MS）可以检测PDMS、PEG、壬苯醇醚-9，但由于目标物所需挥发温度普遍高于仪器承受范围，以及毛细管柱中含有被检测物PDMS，导致无法辨别柱流失导致的假阳性，难以成为主流方法；热解气相色谱-质谱（Py-GC/MS）尤其适合用于检测PDMS，其将PDMS进行裂解，对其裂解后的产物进行检测，不会出现柱流失导致的假阳性并且能够分析检测物聚合度；液相色谱（LC）适用于GC无法分析的分子非挥发性化合物如壬苯醇醚-9；电喷雾电离（ESI）通常用于检测壬苯醇醚-9和PDMS。无论是单独使用还是与凝胶渗透色谱耦合，ESI都具有良好分辨样品的能力。其能够确定分子是环状还是线性形式，从而确认Py-GC-MS获得的结果，但在检测质量超过4 000 Da的化合物时，离子抑制效应会使这些化合物难以检测；基质辅助激光解吸电离可以用于PDMS、PEG的定性和定量分析。结合飞行时间-MS进行检测，是目前这类分析的理想方法。其能够检测大摩尔质量的物质，但无法检测是否存在环状低聚物。该方法比ESI更稳定，可重复性更强。但该方法获得的光谱很复杂，因此很难检测到微量化合物；解吸化学电离-质谱、解吸电喷雾电离-质谱、实时直接分析-质谱等方法也可用于PDMS和PEG的检测。目前对安全套痕迹的检测进行的研究，主要基于安全套的化学特性提出了不同的方法。这些方法的目的基本都是识别安全套润滑剂，并能够对不同的安全套品牌和类型进行分类。但很少有关于错误率和检测限的分析，也没有对安全套残留物或成分进行量化分析以及在不同介质中的变异性和保留时间的相关实验。还需要开展更多的研究，明确已开发方法的潜力和适用范围，并对实验中可能出现的误解进行解释。关键词硅基润滑剂；聚二甲基硅氧烷；安全套；物证分析中图分类号：O657 文献标识码：文章编号：1008-6145(2023)07-0109-08Research status of analytical methods for trace physical evidence left by condoms in sexual assault casesCHEN Qiquan(Department of Forensic Chemistry,Criminal Investigation Police University of China,Shenyang110035,China)Abstract The analysis of condom evidence usually focused on the detection of silicone-based lubricants on the surface of condoms,such as polydimethylsiloxane(PDMS),as well as small amounts of other lubricants such as glycerin,propylene glycol,etc.,and sometimes other functional components polyethylene glycol(PEG),nonoxynol ether-9,etc.and solid particles on the condom.The effective detection methods of PDMS,PEG and nonoxynol ether-9 were summarized from the five perspectives of sample preparation,microscopy analysis,spectroscopic analysis,chromatographic analysis and mass spectrometry analysis.Light microscopy and scanning electron microscopy were commonly used to analyze solid doi:10.3969/j.issn.1008-6145.2023.07.024通信作者陈麒全，学士，研究生在读，主要从事研究微量物证方向收稿日期20230510引用格式陈麒全.安全套遗留微量物证分析研究进展 J.化学分析计量，2023，32（7）：109.CHEN Qiquan.Research status of analytical methods for trace physical evidence left by condoms in sexual assault casesJ.Chemical Analysis and Meterage,2023,32(7):109.109化学分析计量2023 年，第 32卷，第 7 期particles on the surface of condoms;Fourier transform infrared spectroscopy was used to analyze PDMS and PEG,which could identified the relative abundance of sample absorption peaks,but lacks specific identification capabilities,and was mainly used as a screening method.Raman spectroscopy was mainly used for the analysis of PDMS,PEG,nonoxynol ether-9;Nuclear magnetic resonance could be used to analyze PDMS,PEG,nonoxynol ether-9 with high sensitivity and discrimination;Gas chromatography-mass spectrometry(GC-MS)could detect PDMS,PEG,nonoxynol ether-9,but due to the volatilization temperature required by the detected substance was generally higher than the instrument tolerance range and the capillary column contains the detected substance PDMS,resulting in the inability to distinguish the false positives caused by column loss,it had not become the mainstream method;Pyrolysis gas chromatography-mass spectrometry(Py-GC/MS)was particularly suitable for the detection of PDMS,which lysed PDMS,detected the product after its cleavage,did not produce false positives caused by column loss,and could analyzed the polymerization degree of the detection object;Liquid chromatography(LC)was suitable for molecules of non-volatile compounds such as nonoxynol ether-9 that could not be analyzed by GC;Electrospray ionization(ESI)was commonly used to detect nonoxynol ether-9 and PDMS.Whether used alone or coupled to Gel Permeation Chromatography,ESI has the ability to resolve samples well.It can determine whether the molecule is in a cyclic or linear form,thereby confirming the results obtained by Pyrolysis gas chromatography-mass spectrometry,but the ion suppression effect could made these compounds difficult to detect when detecting compounds with masses greater than 4 000 Da;Matrix-assisted laser desorption ionization could be used for qualitative and quantitative analysis of condom lubricants(PDMS,PEG).Detection in combination with time-of-flight-MS was currently ideal for this type of analysis.It was capable of detecting substances with large molar masses,but not the presence of cyclic oligomers.This method was more stable and reproducible than ESI.However,the spectra obtained by this method were complex,so it was difficult to detect trace compounds;Methodssuch as desorption chemical ionization-MS,desorption electrospray ionization-MS,real-time direct analysis-MS could also be used for the detection of PDMS and PEG.At present,different methods had been proposed for the detection of condom traces,mainly based on the chemical