The use of activated charcoal for the concentration and analysis of headspace vapours containing food aroma volatiles

The possibility of using very small quantities of activated charcoal for concentrating aroma volatiles from the headspace vapour over foodstuffs was investigated. Excellent recoveries of a range of organic compounds trapped on 2 mg of charcoal in a glass capillary tube were obtained when the components were desorbed rapidly at 260°C on to a gas chromatographic column, using a specially constructed injection device. In addition, the charcoal traps were found to be highly effective for concentrating volatiles at ambient temperatures from very large (18 litre) volumes of headspace vapour over raw walnuts, a foodstuff having a weak but characteristic aroma. Moreover, the aroma of the heat‐desorbed volatiles was judged by sensory evaluation to closely resemble that of fresh walnuts. The results suggest a considerable potential for charcoal in the headspace analysis of foodstuffs and of other substrates.