Quantitative analysis of pungent and anti-inflammatory phenolic compounds in olive oil by capillary electrophoresis

The first CE procedure for the quantitative determination of pharmacologically relevant secoiridoids in olive oil, oleocanthal and oleacein, is described. Together with their precursors tyrosol and hydroxytyrosol they could be baseline separated in less than 15 min using a borax buffer with pH 9.5, at 25 kV and 30 °C. Method validation confirmed that the procedure is selective, accurate (recovery rates from 94.0 to 104.6%), reproducible (σmax ⩽ 6.8%) and precise (inter-day precision ⩽ 6.4%), and that the compounds do not degrade quickly if non-aqueous acetonitrile is used as solvent. Quantitative results indicated a low occurrence of oleocanthal (0.004-0.021%) and oleacein (0.002-0.048%) in olive oil samples, which is in agreement to published HPLC data. The CE method impresses with its simple instrumental and methodological design, combined with reproducible and valid quantitative results.