Lucena Marcella A M, Ordoñez Carlos, Weber Ingrid T, Torre Mercedes, García-Ruiz Carmen, López-López María
Federal University of Pernambuco, Postgraduate Program in Materials Science (PGMTR/CCEN), Avenida Professor Luiz Freire, S/N, Cidade Universitária, 50740-540 Recife, PE, Brazil; University of Brasília, Chemistry Institute, Laboratory of Inorganic and Materials (LIMA), Campus Universitário Darcy Ribeiro, 70904-970 Brasília, DF, Brazil.
Scientific Police Headquarter, Chemistry Laboratory, Julian Gonzalez Segador S/N, 28002 Madrid, Spain.
Forensic Sci Int. 2017 Nov;280:95-102. doi: 10.1016/j.forsciint.2017.09.013. Epub 2017 Sep 28.
The addition of luminescent markers into ammunition cartridges is an appealing proposal to achieve a greater individual identification of the ammunition. The lanthanide elements present in these luminescent materials act as characteristic chemical markers that, also, offer the great benefit of making gunshot residues (GSR) collection easier. Although the use of luminescent markers offers numerous advantages, and can be a reliable future option in the cartridge ammunition market, little or nothing is known about the interaction of the marker with the ammunition compounds after the shot. For the forensic laboratories, it is of utmost importance to anticipate the commercialization of tagged luminescent ammunition by knowing the type of particles produced after the discharge. That is, to investigate if markers merge with GSR to form single particles or, on the contrary, they form individual particles that travel separately from the GSR particles. In this work, conventional ammunition cartridges tagged with two types of luminescent markers were shot. Then, the particles produced were visualized under UV light on the floor, clothing targets and the shooter. The luminescent particles spread over the floor determined the shooter position and the bullet trajectory. The illumination of the shot targets allows the visualization of the GSR patterns only using a portable UV lamp, avoiding the use of colorimetric test. The GSR particles were collected and subjected to SEM-EDX and Raman spectroscopy analysis to get information about their inorganic and organic composition. The results indicated that part of the marker and the GSR merge and travel together. With this, particles composed by the marker and propellant organic compounds can be identified by Raman spectroscopy, and the unequivocal identification of the GSR and the marker can be achieved by SEM-EDX. Consequently, the luminescent particles detected under UV light improve the evidence collection and offer information about the GSR and the marker. Additionally, this study support the use of luminescent ammunition to study, for example, the transfer or persistence of GSR.
在弹药筒中添加发光标记物是一项颇具吸引力的提议，旨在实现对弹药更精准的个体识别。这些发光材料中存在的镧系元素可作为特征化学标记物，同时还具有极大的优势，即能使枪击残留物（GSR）的收集更加简便。尽管使用发光标记物具有诸多优点，并且在弹药筒市场中可能是一个可靠的未来选择，但对于枪击后标记物与弹药化合物之间的相互作用却知之甚少。对于法医实验室而言，通过了解枪击后产生的颗粒类型来预测标记发光弹药的商业化情况至关重要。也就是说，要研究标记物是否与GSR合并形成单个颗粒，或者相反，它们是否形成与GSR颗粒分开传播的单个颗粒。在这项工作中，对标记有两种发光标记物的传统弹药筒进行了射击。然后，在紫外光下观察在地面、衣物靶标和射击者身上产生的颗粒。散布在地面上的发光颗粒确定了射击者的位置和子弹轨迹。仅使用便携式紫外灯就能照亮射击目标，从而观察到GSR模式，避免了使用比色测试。收集GSR颗粒并进行扫描电子显微镜-能谱仪（SEM-EDX）和拉曼光谱分析，以获取有关其无机和有机成分的信息。结果表明，部分标记物与GSR合并并一起传播。由此，通过拉曼光谱可以识别由标记物和推进剂有机化合物组成的颗粒，并且通过SEM-EDX可以明确识别GSR和标记物。因此，在紫外光下检测到的发光颗粒改善了证据收集，并提供了有关GSR和标记物的信息。此外，本研究支持使用发光弹药来研究例如GSR的转移或持久性。
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