First attempt of odorant quantitation using gas chromatography-olfactometry

An aroma compound was quantitated for the first time by GC-olfactometry (GC -O) on-the basis of the detection frequency of odorants by a panel of 8-12 persons. The method was previously optimized regarding the coincidence of o lfactometric peak apexes and the repeatability of peak height and area over 4 months. The number of required calibration points and the confidence int erval of the curve were investigated. This technique was then tested by qua ntifying a model solution of 1-octen-3-one. The standard addition method wa s found to be unsuitable in this context, but external calibration gave exc ellent results in the ppt range. GC-O was then challenged using one of the most sensitive and selective methods, GC/MS, to quantitate 1-octen-3-one in coffee, a complex aroma. Results showed performances comparable to GC/MS/M S for this odorant, or even better as the latter required 75-500 times more sample to perform the quantitation, However, at such a low concentration, overestimation cannot be excluded with either technique because of possible coelution of odorants or isobaric ions, respectively. These results show t hat GC-olfactometry can compete with the most sensitive and selective techn iques, such as MS, for determination of extremely intense odorants, because little sample preparation is required and there is no need for the synthes is of labeled compounds.