DYNAMIC HEADSPACE GAS-CHROMATOGRAPHIC METHOD FOR DETERMINING VOLATILES IN VIRGIN OLIVE OIL

Dynamic headspace sampling methods prior to capillary gas chromatography are especially suitable in the determination of volatile compounds at a wide range of concentrations, and numerous methods have been developed and applied to very different kinds of samples. In this work, a simple and rapid dynamic headspace technique was developed to determine volatiles present in virgin olive oil samples. Headspace components were swept from 0.5 g of sample at low temperature (40 degrees C) and concentrated on Tenax TA, thermally desorbed and subsequently trapped in a fused-silica cold trap previously cooled to -110 degrees C. They then passed to the capillary column. This system was connected to a mass spectrometer to identify the most important compounds and a comparative study of the main volatiles identified in virgin olive oil samples using other methods was carried out. Sniffing of the components eluted from the chromatographic column was also performed. Different virgin olive oil samples showing different chromatographic profiles were analysed. The differences were mainly quantitative because most compounds were present in all oils analysed, and only the proportions in which these compounds are present varied. Discriminant analysis of these compounds allowed the origin of each sample to be determined with a probability of greater than 90%.