Application of solid-phase microextraction to virgin olive oil quality control.

Volatiles of olive oils from 'tree-picked', 'ground-picked' and both mixed olives were analysed by solid-phase microextraction and gas chromatography with flame ionisation detection (FID). Headspace sampling was carried out for 30min of fibre exposition at 40 degrees C of sampling temperature by the selected 74 microm polydimethylsiloxane/divinylbenzene (PDMS/DVB) fibre. Chromatographic data were analysed by principal components analysis (PCA) and then selected 14 compounds from x-loading of first principal component that provides a differentiation of oils accord its sensorial characterisation. Compounds such as 4-ethylphenol and styrene were identified by gas chromatography-mass spectrometry (GC-MS) in 'ground-picked' olive oils.