Profiling of phenolic compounds in domestic and imported extra virgin olive oils in China by high performance liquid chromatography-electrochemical detection

Abstract

In this study, a high performance liquid chromatography-electrochemical detection (HPLC-ECD) method has been developed for the sensitive determination of 22 phenolic compounds in extra virgin olive oil (EVOO). Chromatographic separation was performed on an Eclipse XDB-C18 column with a gradient methanol/aqueous phosphoric acid elution, and the ECD potential was set at 1.0 V in oxidative mode. Under the optimal conditions, good linearity was obtained for 22 phenolic compounds with coefficients of determination (R2) higher than 0.9971 in the range of 0.005–20.0 μg/mL. The limits of detection (LODs, S/N = 3) for 22 phenolic compounds were in the range of 0.4–6.7 μg/kg by ECD. Satisfactory recoveries ranging from 80.1% to 109.3% were obtained for spiked EVOO samples with relative standard deviations (RSDs) less than 5.4%. The proposed HPLC-ECD method featuring excellent sensitivity and selectivity has been applied to the quantification of phenolic compounds in 61 EVOO samples from seven countries. Good discrimination was achieved between domestic and imported EVOOs based on multivariate statistical approach and their phenolic profiles. These results provide promising perspectives for the use of HPLC-ECD combined with chemometrics for the origin identification of EVOOs.