Developing a comprehensive analytical protocol for forensic sexual lubricant analysis – Part 1: Implementing a sexual lubricant database for forensic casework

IF 2.6 3区医学 Q2 CHEMISTRY, ANALYTICAL Forensic Chemistry Pub Date : 2022-03-01 DOI:10.1016/j.forc.2022.100403

Brooke Baumgarten , Santana Thomas , Nancy Flynn , Mark Marić , Nogc Ty Nguyen , Liansheng Tang , Candice Bridge

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引用次数: 1

Abstract

The increased use of condoms may be one reason why there is a reduced potential of finding DNA evidence in sexual assault cases. This dilemma has led to research in other trace evidence, such as sexual lubricants. In the absence of DNA, the analysis of trace lubricant residue may aid in connecting the suspect to the victim and/or crime scene. In this study, 162 samples from different lubricant manufacturing types were analyzed and classified based on the components identified in the sample. This study developed FTIR, GC–MS, and DART-HRMS methods and protocols that can be used to analyze samples and identify lubricant components for forensic purposes. Neat and solvent extracts of samples were analyzed in triplicate via the DART-HRMS and FTIR; however, only the extracts were analyzed by GC–MS in triplicate. Multivariate statistical techniques included hierarchical cluster analysis, principal component analysis, linear discriminant analysis, Fisher's ratio, and least absolute shrinkage and selection operator (LASSO) regression were used to characterize the lubricants to develop a comprehensive classification scheme for the lubricants. The classification scheme was tested using an internal dataset and an external independent test set to evaluate the accuracy of the developed model(s) for unknown samples. The classification scheme developed from this study and provided along with the database will allow analysts to classify unknown lubricants and lubricant residues found at crime scenes using analytical results from the aforementioned instruments. This research will aid in classifying unknown sexual lubricants based on components indicative of a particular class.

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为法医性润滑剂分析制定全面的分析方案。第1部分:为法医案件工作实施性润滑剂数据库

避孕套使用的增加可能是在性侵犯案件中发现DNA证据的可能性降低的原因之一。这种困境导致了对其他微量证据的研究，比如性润滑剂。在没有DNA的情况下，对微量润滑油残留物的分析可能有助于将嫌疑人与受害者和/或犯罪现场联系起来。本研究对162个不同润滑油制造类型的样品进行了分析，并根据样品中鉴定出的成分进行了分类。本研究开发了FTIR、GC-MS和DART-HRMS方法和协议，可用于分析样品和鉴定法医用途的润滑剂成分。采用DART-HRMS和FTIR对样品的纯提取物和溶剂提取物进行三次分析;然而，只有提取物被GC-MS分析了3个重复。多元统计技术包括层次聚类分析、主成分分析、线性判别分析、Fisher’s ratio、最小绝对收缩和选择算子(LASSO)回归等，对润滑油进行了表征，建立了润滑油的综合分类方案。使用内部数据集和外部独立测试集对分类方案进行测试，以评估所开发模型对未知样本的准确性。根据这项研究开发的分类方案以及与数据库一起提供的分类方案将允许分析人员使用上述仪器的分析结果对犯罪现场发现的未知润滑剂和润滑剂残留物进行分类。这项研究将有助于分类未知的性润滑剂基于成分的指示一个特定类别。

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来源期刊

Forensic Chemistry CHEMISTRY, ANALYTICAL-

CiteScore

5.70

自引率

14.80%

发文量

审稿时长

46 days

期刊介绍： Forensic Chemistry publishes high quality manuscripts focusing on the theory, research and application of any chemical science to forensic analysis. The scope of the journal includes fundamental advancements that result in a better understanding of the evidentiary significance derived from the physical and chemical analysis of materials. The scope of Forensic Chemistry will also include the application and or development of any molecular and atomic spectrochemical technique, electrochemical techniques, sensors, surface characterization techniques, mass spectrometry, nuclear magnetic resonance, chemometrics and statistics, and separation sciences (e.g. chromatography) that provide insight into the forensic analysis of materials. Evidential topics of interest to the journal include, but are not limited to, fingerprint analysis, drug analysis, ignitable liquid residue analysis, explosives detection and analysis, the characterization and comparison of trace evidence (glass, fibers, paints and polymers, tapes, soils and other materials), ink and paper analysis, gunshot residue analysis, synthetic pathways for drugs, toxicology and the analysis and chemistry associated with the components of fingermarks. The journal is particularly interested in receiving manuscripts that report advances in the forensic interpretation of chemical evidence. Technology Readiness Level: When submitting an article to Forensic Chemistry, all authors will be asked to self-assign a Technology Readiness Level (TRL) to their article. The purpose of the TRL system is to help readers understand the level of maturity of an idea or method, to help track the evolution of readiness of a given technique or method, and to help filter published articles by the expected ease of implementation in an operation setting within a crime lab.