Solid-phase extraction and gas chromatographic analysis of phenolic compounds in virgin olive oil

A careful investigation on the potential application of solid phase extraction (SPE)-gas chromatography procedure in the analysis of phenol compounds in virgin olive oils was carried out. In doped refined olive oil samples a comparison between liquid/liquid and SPE extraction evidenced higher recovery when the C18 sorbent phase was employed whereas, in the case of total suppression of residual sylanolic group (C18 EC), only contradictory data was obtained. The same procedures were carried out on 10 genuine samples of virgin olive oil. As observed with the standards, C18 sorbent phase gave higher values compared to C18 EC and the liquid/liquid extraction procedures. Satisfactory results were obtained in the detection of ligstroside aglycon but for the oleuropein aglycon the quantitative is not completely reliable for the overlap of some unknown no-phenol compounds.