Phenolic compounds in olive oil by solid phase extraction – Ultra performance liquid chromatography – Photodiode array detection for varietal characterization

Abstract

An new method for the extraction of phenolic compounds from olive oil has been proposed before the chromatographic analysis by UPLC-PDA (Ultra-Performance Liquid Chromatography-PhotoDiode Array). Recoveries for 20 individual phenolic compounds were compared using three cartridges of solid-phase extraction including C-18, Diol, and DVB (DiVinylBenzene) based cartridges. Diol based cartridge produced the best retention efficiency. The optimized method uses a reduced amount of solvents and allows for the determination of most phenolics in oil samples in less than 10 min. A full discrimination among the most common olive oil varieties was achieved using the relative levels for specific phenolics in the sample. Therefore, based in this study, a fingerprint based on the relative levels for quercetin, luteolin, oleuropein and vanillic acid can be proposed to characterized varietal olive oils. In that way, a detailed composition about phenolic compounds of varietal olive oils would not be needed for discrimination purposes.

Keywords

• Discrimination
• Olive oils
• Olive varieties
• Phenolic compounds
• Solid-phase extraction (SPE)