Study of sampling phases for body odor sampling prior to analysis by TD-GC×GC/ToFMS

Body odor consists of a complex matrix of volatile organic compounds (VOCs), which has garnered increasing interest in fields like medicine for its potential in disease diagnosis. However, the field of body odor analysis is advancing slowly, partly due to a lack of standardized methodologies. Although gas chromatography-mass spectrometry (GC-MS) is widely used for VOC analysis, there is a broad range of sampling and extraction methods, leading to different or even sometimes contradictory results. To move toward standardized procedures, this study compares five sampling phases for direct body odor sampling in terms of analytical cleanliness and VOC trapping/release efficiency: gauze, glass beads, PowerSorb^®, Getxent^® microtubes, and passive sampling pillows (PSP). Thermodesorption was employed to simplify the protocol and minimize contamination or sample loss, which often occurs during multistep processes. Given the matrix's complexity and the need to detect trace-level compounds, comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC/ToFMS) was used to achieve high sensitivity and peak capacity. PSP and PowerSorb^® demonstrated the best performance, with mean recovery yields of 95% and 71%, respectively, and 22% and 10% variability, ensuring good repeatability. These findings, initially obtained under simulated conditions with a synthetic mixture, were validated with real body odor samples, with an optimal sampling duration estimated between 30 min and 1 h. This study not only highlights these effective sampling solutions but also emphasizes the risks associated with using sorbent phases that lack adequate analytical cleanliness (i.e., clean blank) such as gauze.