Centre for Forensic Science, University of Technology, Sydney, Broadway, NSW, Australia.
Forensic Sci Int. 2012 Apr 10;217(1-3):101-6. doi: 10.1016/j.forsciint.2011.10.030. Epub 2011 Nov 1.
Several studies have indicated that there are potential environmental sources of particles resembling inorganic primer found in gunshot residues (GSR); as a consequence examiners are reluctant to unambiguously assign the origin of inorganic particles. If organic gunshot residues (OGSR) were found in combination with inorganic particles, the possibility of environmental sources could be potentially eliminated, thereby significantly enhancing the strength of the evidence. Methods have been previously described whereby GSR specimens can be analysed for the presence of OGSR or inorganic GRS (IGSR). However, no methods have been reported that allow the analysis of both OGSR and IGSR on the same specimen. Described in this article is a direct method using desorption electrospray ionisation-mass spectrometry (DESI-MS) for the detection of methyl centralite (MC), ethyl centralite (EC) and diphenylamine (DPA) on adhesive tape GSR stubs typically used for scanning electron microscopy-energy-dispersive X-ray (SEM-EDX) analysis. The optimisation of numerous parameters was conducted using an experimental design. The results indicate that direct analysis of these organic components of GSR is possible although some limitations were also identified. This initial investigation has also indicated that subjecting stubs to DESI analysis does not interfere with subsequent SEM-EDX analysis of primer residues; therefore the technique described herein allows a comprehensive examination of GSR that would be highly probative in the event that both OGSR and IGSR are detected in the same specimen.
已有多项研究表明，在枪击残留物（GSR）中发现的无机底漆颗粒可能存在潜在的环境来源；因此，鉴定人员不愿明确地将无机颗粒的来源归因于特定环境。如果发现有机枪击残留物（OGSR）与无机颗粒结合在一起，那么环境来源的可能性就可以被排除，从而大大增强证据的力度。之前已经描述了可以分析 GSR 样本中是否存在 OGSR 或无机 GRS（IGSR）的方法。但是，尚未报道可以在同一样本上分析 OGSR 和 IGSR 的方法。本文描述了一种直接使用解吸电喷雾电离质谱法（DESI-MS）检测胶带上 GSR 碎屑中常见的甲基中央体（MC）、乙基中央体（EC）和二苯胺（DPA）的方法，这些胶带上 GSR 碎屑通常用于扫描电子显微镜-能量色散 X 射线（SEM-EDX）分析。通过实验设计对众多参数进行了优化。结果表明，尽管也发现了一些局限性，但可以直接分析 GSR 的这些有机成分。这项初步研究还表明，对碎屑进行 DESI 分析不会干扰随后对底漆残留物的 SEM-EDX 分析；因此，本文所述的技术允许对 GSR 进行全面检查，如果在同一样本中同时检测到 OGSR 和 IGSR，那么该技术将具有高度的证明力。
