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: $ 2.51万
• 依托单位: University of Windsor
• 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=748760
• 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.

分解化学是法医学的一个新兴领域，研究尸体死后的降解途径。软组织的生物化学降解涉及细胞的解体以及脂质、蛋白质、碳水化合物和核酸产物释放到环境中。随着时间的推移，使用先进的色谱和光谱技术分析这些副产品有可能确定与死后时期相关的新的有机标志物。这些信息可供执法部门和法医部门在死亡调查中使用，并可用于改进搜索和恢复技术（如寻尸犬）的培训。然而，目前在加拿大环境中应用这些方法是不可能的，因为化学数据只收集了猪尸体，最近的研究表明，它们不能直接与人类尸体进行比较。由于气候和生物地理学的根本差异，利用美国和澳大利亚温和地区尸体的研究无法应用于加拿大环境。 这项研究旨在描述软组织分解过程中发生的独特化学变化，并确定加拿大东部气候对腐烂速度和过程的影响。研究将在死亡学研究安全地点（SSRT）进行，这是加拿大唯一使用捐赠尸体研究人体分解的设施。在SSRT收集的有机样品将使用全面的二维气相色谱飞行时间质谱法进行分析，这是唯一具有足够分辨率的仪器，可以分离和识别复杂的分解产物。该计划涉及从空气和土壤中系统收集挥发性有机化合物（VOC），以开发一个全面的分解气味数据库。该数据库将用于发现尸体犬在寒冷气候中用于定位受害者遗体的关键VOC。将收集组织、土壤和纺织品样本，以提取和鉴定与死后时间相关的分解化学标志物。对这些标记物的表征将允许更准确地估计自死亡或尸体沉积以来的时间。 这项研究将改变我们对尸体狗如何在加拿大定位分解气味的理解，并将用于改善它们在定位受害者遗体方面的训练和成功。确定新的分解标记对于为执法提供准确的时间框架至关重要，并将通过缩小相关失踪人员记录来帮助识别受害者。从该计划中获得的基础知识将为分解化学研究界制定全球标准。这些成果对加拿大的执法部门和受害者家属都有明显的好处，并通过迅速查明和遣返战争罪或大规模灾难的受害者而产生全球影响。