Evaluation of three gas chromatography-olfactometry methods: comparison ofodour intensity-concentration relationships of eight volatile compounds with sensory headspace data

Three gas chromatography-olfactometry methods, i.e. dilution analysis, dete ction frequency method and posterior intensity method, were evaluated for a ttribution of odour potency to eight volatile compounds at seven concentrat ion levels. Six serial 1:5 dilutions of a solution consisting of 2-butanone , diacetyl, ethyl acetate, 3-methyl-1-butanol, ethyl butyrate, hexanal, 2-h eptanone, alpha -pinene in pentane were analysed by gas chromatography-olfa ctometry. In addition, sensory odour intensity of sunflower oil solutions o f the compounds at eight concentration levels were determined and related t o their headspace concentrations. Posterior intensities correlated reasonab ly well with sensory odour intensities. Detection frequency data were also highly correlated, whereas dilution analysis led to more diverting results, A large variance among subjects was observed. Therefore, a group of assess ors is considered a prerequisite for reliable gas chromatography-olfactomet ry analysis. (C) 2001 Elsevier Science Ltd. All rights reserved.