ABOV: A Novel System of Direct Headspace Skin Sampling to Study Human Body Odor

Chemicals emitted by the human body convey information about the individuals. However, our understanding of the chemical underpinnings of human chemical communication remains limited, partly due to methodological constraints. Here, we describe a novel sampling technique, named ABOV (Analysis of Body Odor Volatiles), for analyzing the chemical composition of human skin odor. The ABOV device was designed to be easy to use and comfortable, adaptable to different contexts and body parts, and to collect in a non-contact manner airborne chemicals potentially involved in chemical communication. Twenty participants were sampled with this technique in their right and left axillae and neck, and their chemical profiles were obtained through gas chromatography-mass spectrometry (GC-MS) analysis. We robustly showed higher similarity of odor profiles between left/right sides of a given individual than between his/her odor sources (axilla vs. neck) or - even more prominently - than between different individuals. Further, exploratory analyses (PLS-DA) confirmed that the axilla and neck significantly differ in their chemical profiles, and that differences between men's and women's body odor profiles are also present although less pronounced. Several compounds were identified as being more characteristic of one source or sex than the other, and we concluded that predicting sex based on skin volatile profiles has limited reliability (at best 34% error) while prediction reliability was rather good for odor source (11% error). Overall, the novel device ABOV may be used in the future for ecological body odor sampling, even on moving subjects during behavioral experiments, to further investigate the chemical bases of human odor diversity and chemical communication.