Potential of direct immersion solid-phase microextraction to characterize dissolved volatile organic compounds released by submerged decaying rat cadavers

The decomposition process involves the degradation of carbohydrates, nucleic acids, proteins and fats, and leads to the release of volatile organic compounds (VOCs) among many other decomposition by-products. Despite the extensive literature on the VOCs emitted in the air from vertebrate corpses, there is a lack of research dedicated to aquatic decomposition. In this study, we aimed to evaluate the potential of direct immersion solid-phase microextraction gas chromatography coupled with mass spectrometry (DI-SPME/GC/MS) to characterize dissolved cadaveric VOCs. Dimethyl disulphide and indole -two compounds commonly released during decomposition- were selected to evaluate and set the optimal methodological parameters, which were found to be 10 min of collection performed under 27.5 °C and a stirring rate of 250 rpm. Using responsive surface methodology, the obtained curves highlighted the appropriate conditions for the dissolved cadaveric volatilome analysis. The method allows to trap 17 dissolved cadaveric VOCs, including commonly encountered compounds such as dimethyl disulfide, 9-hexanoic acid, dimethyl trisulfide and indole. DI-SPME/GC/MS has therefore potential for the identification of dissolved cadaveric VOCs, pending further tests are performed to optimize the method and make it capable of detecting all dissolved VOCs, through all stages of decomposition.