Nic Daeid Niamh, Yu Holly A, Beardah Matthew S
Centre for Anatomy and Human Identification, School of Science and Engineering, University of Dundee, Dow Street, Dundee DD1 5EH, UK.
Centre for Anatomy and Human Identification, School of Science and Engineering, University of Dundee, Dow Street, Dundee DD1 5EH, UK; Department of Chemistry, Curtin University, GPO Box U1987, Perth, WA 6845, Australia.
Sci Justice. 2017 Mar;57(2):95-100. doi: 10.1016/j.scijus.2016.10.007. Epub 2016 Nov 5.
Explosives residues are often collected from explosion scenes, and from surfaces suspected of being in contact with explosives, by swabbing with solvent-wetted cotton swabs. It is vital that any explosives traces present on the swabs are successfully extracted and detected when received in a laboratory. However, a 2007 proficiency test initiated by the European Network of Forensic Science Institutes (ENFSI) Expert Working Group on Explosives involving TNT-spiked cotton swabs highlighted that explosives may not always be detected from such samples. This paper outlines work performed to determine potential reasons for this finding. Cotton swabs were spiked using a solution of TNT and stored in nylon bags and glass vials for periods of 1, 2 and 4weeks. Simulated swab extracts were also prepared and investigated. The samples were stored in a freezer, or at room temperature either in the dark or exposed to daylight. Overall, the cotton swabs stored at room temperature and exposed to daylight showed a very rapid loss of TNT over time, whereas cotton swabs stored in the freezer, and all simulated swab extracts, gave high recoveries over time. These results will be of benefit for practicing forensic explosives laboratories and for persons undertaking cold-case reviews involving explosive-based samples.
爆炸物残留物通常通过用溶剂浸湿的棉签擦拭，从爆炸现场以及疑似与爆炸物接触的表面收集。至关重要的是，当棉签被送到实验室时，其上存在的任何爆炸物痕迹都要能被成功提取和检测出来。然而，2007年由欧洲法医学研究所网络（ENFSI）爆炸物专家工作组发起的一项涉及加有三硝基甲苯（TNT）的棉签的能力验证试验凸显出，此类样本未必总能检测出爆炸物。本文概述了为确定这一发现的潜在原因而开展的工作。用TNT溶液对棉签进行加样，并将其储存在尼龙袋和玻璃瓶中1周、2周和4周。还制备并研究了模拟棉签提取物。样本被储存在冰箱中，或在室温下置于暗处或暴露于日光下。总体而言，室温下暴露于日光中的棉签显示随着时间推移TNT损失非常迅速，而储存在冰箱中的棉签以及所有模拟棉签提取物随着时间推移回收率都很高。这些结果将对实际操作的法医爆炸物实验室以及对涉及基于爆炸物样本的冷案复查人员有益。
