The Air Up There: Skin VOCs

By: Katie Schaefer, C&T magazine

Posted: October 30, 2008, from the November 2008 issue of Cosmetics & Toiletries.

page 2 of 3

“Vapor phase chemicals are lighter and smaller and more likely to cause odor,” added Preti, who noted that it was necessary to take samples from the skin as well. The extracts from the skin’s surface were produced by applying an ethanol/hexane mixture to the subject’s forearm that was then pipetted into a cylinder pressed against the skin.

The SPME and the solvent samples both were analyzed by age and gender. The groups included young male (≤ 40), older male (> 40), young female (≤ 40) and older female (>40). Although both samples were processed with the GC/MS apparatus, the solvent samples were also processed with a gas chromatograph fitted with flame photometric detection.

Age and VOC Content
VOCs found in the headspace of unfragranced soap and in the air of the room were subtracted from the results to determine the VOCs found in the skin. Of the 92 compounds found, 58 were detected in SPME samples, 49 were present in solvent extracts, and 15 were found in both. Preti and his team discovered that many of the compounds came from exogenous sources and that, although subjects were separated by age, no significant differences in the relative amounts of compounds between men and women were noted.

“The compounds found in the subjects across age ranges were similar. Certain compounds were present in greater amounts in older individuals and [others] were in greater quantities in younger individuals,” explained Preti. Those compounds found in greater amounts in the older subset included dimethylsulphone, benzothiazole and nonanal, although not C₉ aldehyde, 2-nonenal, suggesting the absence of an aging odor in some individuals. In addition, researchers found considerable exogenous VOCs derived from consumer products.

The Future of VOC Reseach
The VOC profiles of skin could have future applications, according to Preti. Using the same VOC method to study basal cell tumors, Preti’s team discovered a different chemical compound profile than for healthy control subjects. Dimethylsulphone, benzothiazole and nonanal were found to act as biomarkers of older age but these were not reported in the Japanese study. Their presence here could be attributed to regional differences.