Sampling method development and optimization in view of human hand odor analysis by thermal desorption coupled with gas chromatography and mass spectrometry.

Abstract

Forensic profiling of human odor is challenging and would be useful to support information provided by dogs in courts of justice. Analyses of volatile compounds constitutive of human odor are commonly performed with gas chromatography coupled with mass spectrometry. All developed methods and sampling prototypes have to be easy to use in the field by crime scene investigators. This paper will focus on techniques for human hand odor sampling prior to analysis by a thermodesorption device coupled with gas chromatography and mass spectrometry. Thermodesorption and gas chromatography methods were developed using a sorbent phase spiked with a mixture of 80 compounds representative of human hand odor. Then, the crucial sampling step was performed indirectly with a homemade device based on air suction and trapping on a sorbent. This indirect sampling device was evaluated with the same synthetic mixture for optimization. An innovative polymer sorbent called Sorb-Star® was compared to classic Tenax TA® packed tubes. Sorb-Star® provided similar recovery to Tenax TA® packed tubes and a smaller pooled coefficient of variation (6 vs 13%). Thus, it appeared to be fully suited to the indirect sampling of human hand odor. The developed methods were successfully applied to real samples, the ultimate aim being the comparison of a suspect's sample to a sample collected from a crime scene.