Classification of extra virgin olive oils according to their geographical origin using phenolic compound profiles obtained by capillary electrochromatography

A simple and reliable method for the evaluation of the phenolic fraction of extra virgin olive oils (EVOO) by capillary electrochromatography (CEC) with UV–Vis detection, using lauryl acrylate (LA) ester-based monolithic columns, has been developed. The percentages of the porogenic solvents in the polymerization mixture, and the mobile phase composition, were optimized. The optimum monolith was obtained with a monomers/porogens ratio of 40:60% (wt/wt) using a LA/1,3-butanediol diacrylate ratio of 70:30% (wt/wt) and a 1,4-butanediol/1-propanol ratio of 25:75% (wt/wt). A satisfactory resolution between the phenolic compounds was achieved in less than 25 min with a 15:85 (v/v) ACN–water buffer containing 5 mM formic acid at pH 3.0. The method was applied to the analysis of the phenolic fraction of EVOO samples. Using linear discriminant analysis of the CEC phenolic profiles, the EVOO samples belonging to three different geographical origins (Croatia, Italy and Spain) were correctly classified with an excellent resolution among all the categories.