Department of Forensic and Investigative Science, West Virginia University, Morgantown, West Virginia, USA.
J Forensic Sci. 2022 Jul;67(4):1450-1460. doi: 10.1111/1556-4029.15049. Epub 2022 Apr 30.
Analysis of gunshot residue currently lacks effective screening methods that can be implemented in real time at the crime scene. Historically, SEM-EDS has been the standard for analysis; however, advances in technology have brought portable instrumentation to the forefront of forensic science disciplines, including the screening of GSR. This study proposes electrochemical methods with disposable screen-printed carbon electrodes for GSR screening at the laboratory and points of care due to their rapid, cost-efficient, and compact platform. GSR residues were extracted from typical aluminum/carbon adhesive collection stubs and analyzed via square-wave anodic stripping voltammetry. Benchtop and portable electrochemical instruments were compared for the assessment and classification of authentic shooter samples by monitoring a panel of inorganic and organic GSR elements and compounds including lead, antimony, copper, 2,4-dinitrotoluene, diphenylamine, nitroglycerin, and ethyl centralite. The evaluation included the assessment of figures of merit and performance measures from quality controls, nonshooter, and shooter data sets. Samples collected from the hands of 200 background individuals (nonshooters), and shooters who fired leaded ammunition (100) and lead-free ammunition (50) were analyzed by the benchtop and portable systems with accuracies of 95.7% and 96.5%, respectively. The findings indicate that electrochemical methods are fast, sensitive, and specific for the identification of inorganic and organic gunshot residues. The portable potentiostat provided results comparable with the benchtop system, serving as a proof-of-concept to transition this methodology to crime scenes for a practical and inexpensive GSR screening that could reduce backlogs, improve investigative leads, and increase the impact of gunshot residues in forensic science.
目前，对射击残留物的分析缺乏能够在犯罪现场实时实施的有效筛选方法。从历史上看，SEM-EDS 一直是分析的标准；然而，技术的进步使便携式仪器成为法医学科的前沿，包括 GSR 的筛选。由于其快速、经济高效和紧凑的平台，本研究提出了用于实验室和护理点 GSR 筛选的电化学方法和一次性丝网印刷碳电极。通过方波阳极溶出伏安法从典型的铝/碳粘性收集 stub 中提取 GSR 残留物，并进行分析。比较了台式和便携式电化学仪器，通过监测一组无机和有机 GSR 元素和化合物（包括铅、锑、铜、2,4-二硝基甲苯、二苯胺、硝化甘油和乙基中央体），对真实射手样品进行评估和分类。评估包括对质量控制、非射手和射手数据集的性能指标和性能措施的评估。使用台式和便携式系统分析了来自 200 名背景个体（非射手）和使用含铅弹药（100 名）和无铅弹药（50 名）射击的射手的手部收集的样品，其准确率分别为 95.7%和 96.5%。研究结果表明，电化学方法快速、灵敏、专一地用于识别无机和有机射击残留物。便携式电化学工作站提供的结果与台式系统相当，这为将该方法转移到犯罪现场进行实际且廉价的 GSR 筛选提供了概念验证，这可以减少积压，改善调查线索，并提高射击残留物在法医学中的影响。
