The Differentiation of the Volatile Organic Signatures of Individuals Through SPME‐GC/MS of Characteristic Human Scent Compounds

Abstract

Human scent evidence is utilized as an investigative tool through canine scent discriminations based on the premise that human scent is an individualizing characteristic. This study describes the development of what is effectively a human scent barcode consisting of the relative ratios of an individual's "primary odor" compounds utilized to determine a reproducible and individualizing profile which can be stored in a searchable database for a proof of concept of human scent as a biometric measure. Triplicate hand odor samples were evaluated from 10 subjects utilizing solid phase micro-extraction gas chromatography/mass spectrometry (SPME-GC/MS) and compared via Spearman Rank Correlations. Narrowing the compounds considered for each subject to only those common in all three samples, or a subject's "primary odor constituents," produced a greater degree of both individualization and discrimination; at both correlation thresholds of 0.9 and 0.8, the individuals were correctly discriminated and identified in 99.54% of the cases.

High throughput volatile fatty acid skin metabolite profiling by thermal desorption secondary electrospray ionisation mass spectrometry

“…Individual skin profiles have been developed as 'barcodes' of scent for forensic [21] and diagnostic application [22], and gender and age specific signatures have been proposed as contributing factors to an individual's profile [23][24][25][26]. Olfactory analysis, either in-vivo or by organoleptic analysis of chromatographic eluents [27], combined with analytical measurement have established levels of odour to correlate with VSCs and VFAs, with 3-methyl-2-hexenoic acid cited as a critical molecular factor [26][27][28].…”

Resistance of human odours to extremely high temperature as revealed by trained dogs

“…The current study verified that human scent can survive extreme mechanical and thermal conditions associated with an explosion and burning through the ability of canines to correctly identify individuals using scent collected from exploded pipe bomb fragments (Stockham et al 2004;Curran et al 2010b). Although these studies have shown that the specially trained dogs can locate and identify individuals, who had been in contact with improvised explosive devices, on the basis of the scent samples collected from items recovered at a postblast scene (Curran et al 2010b), it remained to be elucidated which temperature is critical for human scent survival, how long such a temperature has to be in effect, etc.…”

“…Although these studies have shown that the specially trained dogs can locate and identify individuals, who had been in contact with improvised explosive devices, on the basis of the scent samples collected from items recovered at a postblast scene (Curran et al 2010b), it remained to be elucidated which temperature is critical for human scent survival, how long such a temperature has to be in effect, etc. Thus the purpose of the study was to determine the temperature ceiling, which degrades the human scent so that the dog would not be able to identify it.…”

Analysis of pattern recognition and dimensionality reduction techniques for odor biometrics

“…The relation among the chemicals compounds that produce this scent remains constant over time even with changes in the diet or other transitory factors. Some studies [9,31] suggest that this primary odor depends on genetic factors thus, these compounds allow people identification. Furthermore, this genetic propensity by every individual to produce specific compounds has been reported even in studies with monozygotic twins [31], in which high correlations between the compounds of both siblings are found.…”

“…Curran et al [9] propose to classify the body odor in three different categories depending on the permanence of the odor. The primary odor is our individual fragrance generated by our body.…”