Analysis of human sweat volatiles: An example of pattern recognition in the analysis and interpretation of gas chromatograms

Abstract

AbstractThe analysis of the volatile components of human body odour is described with a view to establishing how individual identity can be reflected in an odour profile. In order to get good chromatographic replication, a recirculating system was built to load the samples of axillary sweat head‐space into Tenax concentrating traps. The loading temperature and humidity could be controlled and trace volatiles concentrated. The head‐space samples were desorbed from the trap and analysed by GLC. The GC/FID was interfaced with an ATARI ST 1040 computer which stored the output on disc. Pairs of chromatograms were then compared in a pattern‐matching programme which allowed irrelevant differences, such as variations in running time and sample size, to be corrected and then various match parameters to be measured. These were alignment coefficient, profile correlation. Euclidian distance and box car distance. The whole and selected parts of the chromatograms could be matched so that each range of volatiles could be assessed for its contribution to an identity signal.The pattern of sweat volatiles from two pairs of identical twins showed significantly higher match correlations than that of unrelated people. The range of compounds eluting between 80 and 150 C showed the highest match correlations.These techniques could be used to match chromatograms from any source, for example, in drugs and pesticide research, environmental monitoring, food, flavour and perfume analysis or clinical and forensic investigations.