Identifying the transition from ante-mortem to post-mortem odor in cadavers in an outdoor environment

This study investigates the transition from ante-mortem to post-mortem odor in human remains during the early post-mortem period in an outdoor environment. Three cadavers (donors) were placed at an outdoor human decomposition facility, and volatile organic compounds (VOCs) were collected and analyzed using thermal desorption coupled with comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (TD-GC × GC-TOFMS). The key findings revealed that nitrogen-containing compounds were predominant in early post-mortem VOC profiles, driven by enzymatic and bacterial activity. Esters, alcohols, and halogenated compounds were also identified, with esters linked to microbial transformation and alcohols possibly formed by lipid peroxidation. Ante-mortem VOCs were persistent across samples, influenced by skin microbiota and environmental factors like UV radiation, complicating the detection of decomposition odor. Post-mortem VOCs became more prominent after ADD 73.4(experimental day 3), signaling the transition to the bloat stage of decomposition. Variations in sample collection methods and external factors such as temperature were found to affect VOC abundances. This study provides critical insights into odor transition and has implications for the use of search and rescue (SAR) and human remains detection (HRD) dogs. Further research is needed to standardize methods and assess odor transitions across diverse environments and seasons.