| This research aims to elucidate the decomposition mechanisms of animal carcasses that might yield forensic clues in the investigation of human remains. Variable environmental conditions, the presence of microorganisms, the disposal mode of the animal or human remains, as well as the amount of time elapsed since death greatly influence the emission profile of the volatile organic compounds (VOCs). In this study, the influence of environmental media (i.e. soil, sand, water) in the decomposition process was minimized by conducting the study of decomposing tissues in glass vessels, configured with a leak-proof design for efficient collection of compounds emitted from the degradation of tissues. Samples were collected approximately 3 times a week over a period of ten weeks using pre-evacuated bottles that were subsequently analyzed by gas chromatography-mass spectrometry (GC-MS) with analyte enrichment on a 3-trap preconcentrator.;The predominant classes of compounds found in decomposing tissues include: alkanes, alkenes, ketones, sulfur-containing compounds, esters, and aldehydes. Aldehydes and esters form more readily in organs, skin, bones, and muscle. Ketones were found in the organ and bone samples while alkenes were found predominantly in bone. Alkanes and alcohols were found more frequently in blood. The presence of sulfur-containing compounds, such as carbon disulfide, methanethiol, dimethylsulfide, dimethyldisulfide, and dimethyltrisulfide, could be linked to the biochemical degradation of sulfur-containing amino acids like methionine, cystine, and cysteine that constitute the swine tissues or organs. The presence of dimethyldisulfide and dimethyltrisulfide may be linked to cystine, which is composed of two cysteine units and is commonly found in collagen (i.e. connective tissue) and keratin (hooves and hair).;The cryofocusing GC-MS technique based on a 60-meter column with dimethylsiloxane stationary phase was able to detect alkanes with carbon numbers ranging from 3 to 14 as well as aliphatic alcohols with 2-8 carbons. The detection limits of the compounds released from the decomposition of porcine tissues are generally in the 0.1 to 20 parts per billion levels. With the current study of tissue-specific or organ-specific decomposition studies, valuable information will be gleaned for strengthening the credibility of forensic evidence involving odor analysis pertaining to human decomposition. |
