Determination of phenolic acids in olive oil by capillary electrophoresis

A CZE method for the separation and quantitation of phenolic acids (cinnamic, syringic, p—coumaric, vanillic, caffeic, 3, 4—dihydroxyphenylacetic, protocatechuic), extracted from extra virgin olive oil, was developed. The sample preparation involved the LLE and SPE extraction methods. CE separation was performed in a fused silica capillary of I. D. = 50μm using as a BGE 40 mM borate buffer at pH = 9.2. The separation voltage was 18kV with corresponding current of 2728 μA. Detection was accomplished with UV—detector at λ = 200nm. The proposed method was fully validated. A good repeatability of migration time (RSD% ranged from 0.81 to 1.63) and of corrected peak area ( RSD% from 2.89 to 5.77) was obtained. The linearity of detector response in the range from 5 to 50 ppm was checked, obtaining the correlation coefficient R2 values in the range: 0.9919—0.9997. Some phenolic acids in real oil samples were detected and quantified with the proposed method.