A validated method for the determination of selected phenolics in olive oil using high-performance liquid chromatography with coulometric electrochemical detection and a fused-core column

A liquid chromatographic method with a coulometric electrochemical detector (ECD) and a fused-core column was developed for the quantification of the olive oil phenolics tyrosol, hydroxytyrosol, oleuropein, pinoresinol, and caffeic, ferulic, vanillic, and p-coumaric acid. The method was validated according to guidelines of the U.S. Food and Drug Administration. The selectivity, linearity, lower limit of quantification (LOQ), lower limit of detection (LOD), precision, accuracy, recovery, as well as the stabilities of the phenolic standards and quality control samples were determined. The separation of the eight phenolic compounds was achieved within 16 min and the total analysis time (35 min) was ca. 3-fold shorter than that of conventional HPLC methods. The LOQ range was 0.3-15.3 ng/mL, which is at least 5-fold lower than those of other methods. Recovery was between 75% and 101%. Overall the method has the advantages of being sensitive, selective, fast and provides simultaneous qualitative and quantitative analysis of phenolics.