Applicability of emanating volatile organic compounds from various forensic specimens for individual differentiation

Trace biological materials contain volatile profiles that have yet to be evaluated to determine their value in forensic investigations. The volatiles released by different biological specimens (hand odor, hair, fingernails and saliva) collected from twenty individuals were identified using a solid phase microextraction-gas chromatography-mass spectrometry method. The human scent compounds from each specimen, per subject, were evaluated using Spearman rank correlation to assess the applicability of these compounds for the differentiation of individuals. The volatile organic compounds from each specimen type were readily identified and discriminated. When conducting inter-subject discrimination within a single specimen type, greater than 98.9% of the samples, or individuals, were differentiated for all specimen types. When conducting inter-subject discrimination among the four specimen types 99.6% of the samples were differentiated, at the 0.9 correlation coefficient threshold. Additionally, the only occurrence of cross-correlation between specimen types was observed between hair and fingernails while there were no cross-correlations with hand odor or saliva thereby demonstrating the distinctiveness of these specimens.