Characterising chemical markers of decomposition to advance death investigations

表征分解的化学标记以推进死亡调查

• 批准号: RGPIN-2019-06098
• 负责人: Forbes, Shari
• 金额: $ 0.98万
• 依托单位: Université du Québec à Trois-Rivières
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=748761
• 关键词: Characterising; chemical; markers; decomposition; advance

Decomposition chemistry is an emerging field of forensic science that studies the degradation pathways in a body postmortem. The biochemical degradation of soft tissue involves the disintegration of cells and the release of lipid, protein, carbohydrate, and nucleic acid products to the environment. Analysis of these by-products using advanced chromatographic and spectroscopic techniques over time has the potential to identify novel organic markers that correlate with the postmortem period. This information can be used by law enforcement and forensic services in death investigations, and to improve training in search and recovery techniques (e.g. cadaver dogs). However, current application of these methods in Canadian environments is not possible as chemical data has only been collected using pig carcasses, and recent research has shown that they are not directly comparable to human cadavers. Studies that have utilised cadavers in milder regions of the USA and Australia cannot be applied to Canadian environments due to fundamental differences in climate and biogeography. This research aims to characterize the unique chemical changes that occur during soft tissue decomposition and to determine the impact of the eastern Canadian climate on the rate and process of decay. Research will be conducted at the Secure Site for Research in Thanatology (SSRT), the only facility in Canada for the study of human decomposition using donated cadavers. Organic samples collected at SSRT will be analysed using comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry, the only instrument with sufficient resolution to separate and identify the complex products of decomposition. The program involves the systematic collection of volatile organic compounds (VOC) from air and soil to develop a comprehensive decomposition odour database. The database will be used to discover the key VOCs used by cadaver dogs for locating victim remains in a cold climate. Samples of tissue, soil and textiles will be collected to extract and identify chemical markers of decomposition that correlate with the postmortem period. Characterisation of these markers will allow for more accurate estimations of time since death or deposition of a body. The research will change our understanding of how cadaver dogs locate decomposition odour in Canada and will be used to improve their training and success in locating victim remains. Identification of novel decomposition markers are essential for providing accurate timeframes to law enforcement and will aid victim identification by narrowing pertinent missing persons records. The fundamental knowledge gained from this program will set a global standard for the decomposition chemistry research community. The outcomes have a clear benefit to both law enforcement and families of victims in Canada, as well as global implications through the rapid identification and repatriation of victims of war crimes or mass disasters.

分解化学是法医科学的新兴领域，研究了身体验尸的降解途径。软组织的生化降解涉及细胞分解以及脂质，蛋白质，碳水化合物和核酸产物的释放到环境中。随着时间的推移，使用高级色谱和光谱技术对这些副产品进行分析具有鉴定与事后时期相关的新型有机标记。执法和法医服务可以在死亡调查中使用此信息，并改善搜索和恢复技术的培训（例如尸体狗）。但是，由于仅使用猪尸体收集了化学数据，因此无法在加拿大环境中使用这些方法，并且最近的研究表明它们与人尸体不直接可比。由于气候和生物地理学的根本差异，美国和澳大利亚较温和的地区使用尸体的研究不能应用于加拿大环境。 这项研究旨在表征软组织分解过程中发生的独特化学变化，并确定东部加拿大气候对衰减速率和过程的影响。研究将在Thalagology研究的安全地点（SSRT）进行，这是加拿大使用捐赠尸体研究人类分解的唯一设施。将使用全面的二维气相色谱时间质谱法分析在SSRT上收集的有机样品，这是唯一具有足够分辨率的仪器，可以分离和识别分解的复杂产物。该程序涉及从空气和土壤中系统收集挥发性有机化合物（VOC），以开发全面的分解气味数据库。该数据库将用于发现Cadaver Dogs用于将受害者遗体定位的关键VOC处于寒冷的气候。将收集组织，土壤和纺织品的样品，以提取和识别与死后时期相关的分解化学标志物。这些标记的表征将允许自死亡或身体沉积以来的时间进行更准确的估计。 这项研究将改变我们对尸体如何在加拿大找到分解气味的理解，并将用于改善他们的训练和成功定位受害者的遗体。识别新颖的分解标记对于为执法提供准确的时间表至关重要，并通过缩小相关的失踪人员记录来帮助受害者身份。从该计划中获得的基本知识将为分解化学研究界树立全球标准。这些结果对加拿大的执法和受害者家庭都有明显的好处，以及通过快速认同和遣返战争罪行或大规模灾难的受害者的全球影响。