Determination of Polyphenols in Commercial Extra Virgin Olive Oils from Different Origins (Mediterranean and South American Countries) by Liquid Chromatography–Electrospray Time-of-Flight Mass Spectrometry

Abstract

The phenolic profiles of extra virgin olive oil samples from different origins and varieties have been studied and compared. The determination of 13 target polyphenols (gallic acid, hydroxytyrosol, tyrosol, vanillic acid, caffeic acid, syringic acid, gibberellic acid, p-coumaric acid, ferulic acid, oleuropein, resveratrol, luteolin, and apigenin) was carried out by liquid chromatography using a column (C18, 4.6 × 100 mm) with small particle size (1.8 μm) and mass spectrometric detection using electrospray time-of-flight mass spectrometry (LC–TOFMS). Prior to LC–MS analysis, a solid-phase extraction procedure using SPE-Diol cartridges was used to isolate the polyphenol fraction. The full-scan mass spectra acquisition by TOF analyzers offered the possibility of searching for a large number of compounds by means of accurate mass information of the molecules and allowed the detection of other phenolic compounds not included in the initial target list, namely ligstroside aglycon, oleuropein aglycon, and elenolic acid. The proposed method was successfully applied to the analysis of 78 samples of extra virgin olive oil collected from ten different countries: Argentina (5), Chile (6), France (1), Greece (1), Italy (1), Morocco (4), Peru (32), Portugal (1), Spain (26), and Syria (1). No qualitative differences in the composition of the phenolic fraction were found between samples of different origins. Only quantitative differences were observed for some phenolic compounds. Therefore, further studies are still needed to exploit the possibility of using phenolic profile as a marker for olive oil geographical origin.