Influence of assessors' qualities and analytical conditions on gas chromatography-olfactometry analysis

Gas chromatography-olfactometry is a commonly used technique for analysis o f odour active compounds. The present study deals with the influence of met hodological factors on gas chromatography-olfactometry data, i.e. assessors qualities and analytical conditions. With respect to the assessors' qualit ies, the effects of training and fatigue/alertness were studied. Analytical conditions included concentration aspects resulting from varying chromatog raphic peak shapes and humidified air flow rates at the sniff port, The com pounds 2-butanone, diacetyl, ethyl acetate, 3-methyl-1-butanol, ethyl butyr ate, hexanal, 2-heptanone and alpha -pinene were analysed by gas chromatogr aphy-olfactometry using the detection frequency and posterior intensity met hod for collection and processing of the data. Training did not affect the detection of the odour active compounds, but it decreased noise levels cons iderably. No significant effect of fatigue or decreased alertness was found for the 45-min sessions. The data were influenced by extreme peak shape di fferences and an intensity optimum was observed for all compounds at a humi dified air flow rate of 6 ml min(-1). Assessors' qualities and analytical c onditions were shown to affect GC-O data and require optimisation for sound gas chromatography-olfactometry analysis.