Identifying VOCs from human remains detectable in water using comprehensive two-dimensional gas chromatography

Understanding the volatile organic compounds (VOCs) emitted during human decomposition is crucial for search and recovery investigations and the development of improved human remains detection methods. However, the influence of water on human decomposition, and particularly the release of VOCs has received minimal attention compared to terrestrial scenarios. This knowledge gap is highly relevant for training human remains detection (HRD) dogs, as they are deployed in various scenarios, including land and water searches, yet little is known about the VOC profiles produced by human remains in these different environments. The aim of this study was to establish a proof-of-concept methodology for collecting VOCs from submerged remains. Sorbent tubes and thin-film solid phase microextraction (TF-SPME) were utilized as neither have been studied for this purpose previously. Human remains were submerged in a tank of water. Headspace samples were collected by placing a metal hood over the tank to trap VOCs, which were then drawn into a sorbent tube via an air sampling pump. Water samples were collected for direct immersion utilizing TF-SPME membranes in the laboratory. Comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry combined with thermal desorption was employed to analyze both sample types. The sorbent tube method identified 42 compounds while the TF-SPME technique identified 34 compounds. Overall, this study successfully demonstrated the feasibility of both VOC collection and analysis methods for human remains decomposition in water.