| Summary: | 碩士 === 中央警察大學 === 鑑識科學研究所 === 104 === Rare evidence and insufficient methods are main limitations in practical forensic biofluid identification. To solve the problems, the aims of this study is to detect biofluid-specific metabolites by using LC-Q-ToF mass spectrometer. Firstly, the applicability of 6 solvents for extraction of 6 different biofluids (urine, semen, venous blood, menstrual blood, saliva and sweat), each of them from 6 individuals, were evaluated. As methanol/acetone (v/v 3:7) was observed to detect the most metabolites in the biofluids, except for the menstrual blood, and it was thus taken as the extraction solvent in following experiments. Among biofluid metabolome, semen was observed with the most metabolites detected (81.83±9.45 kinds) while saliva was the least (42.50±3.39 kinds). Furthermore, metabolomic mutuality ratio for inter-individual similarity showed the lowest (29.96%±4.65%) percentage for sweat and the highest (52.03%±3.98%) for saliva. For biofluid-specific metabolites searching, 3 urine-specific metabolites (C10H17N3O6, C15H29NO4 and one of C10H19NO8, C10H16O8 and C11H19N2O5), 6 semen-specific metabolites (C20H28O4, C20H30O4, C20H30O5, C20H32O5, C20H35NO15 and C9H11N5O2) and 1 blood-specific metabolite (C27H44O2) were selected. For further distinguishing between venous and menstrual blood, C24H28O5, which was not detected in menstrual blood, was observed in venous blood metabolome. In this study, saliva and sweat were failed to identify any biofluid-specific metabolites. All metabolites claimed above to be biofluid-specific showed good reproducibility in both intra-individual and inter-individual tests, and no inter-biofluid false-positive results. The human biofluid identification system established in this study by LC-Q-ToF mass spectrometry would be a potential technique for practical forensic biofluid identification.
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