Determination of some phenolic acids by ultra high performance liquid chromatography (UHPLC) and method validation

In this study, fast and selective ultra high performance liquid chromatography (UHPLC) method has been developed and validated for the determination of certain important phenolic acids including Protocatechuic acid (PCA), p-Hydroxybenzoic acid (p-HBZ), Caffeic acid (CAF), Syringic acid, (SYR) p-Coumaric acid (p-COU), t-Ferulic acid (t-FER), Rosmarinic acid (ROS) and t-Cinnamic acid (t-CIN) in plums and food supplements. Phenolic acids were determined by UV detector at a wavelength of 280 nm on Agilent Zorbax Eclipse Plus C8 (3.0 mm×150 mm×1.8 µm) column and using a mobile phase A (water:methanol:formic acid; 88:10:2; v/v/v), B (water:methanol:formic acid; 8:90:2; v/v/v). The flow rate was 0.4 ml/min and the injection volume was 10 µl. The method was validated according to the precision, accuracy, linearity, limit of detection (LOD), limit of quantification (LOQ) and stability parameters. High correlation coefficients (r2 = 0.9991-0.9999) were obtained for the phenolic acids. The method was reproducible which were found in intraday and interday precision experiments, with RSD% values less than 3.82%. The experiments were carried out in different plum species and food supplements including pycnogenol and supradyn tablets. Solid phase extraction (SPE) technique with C18-OH column was performed for the purification of phenolic acids from plum juice. Keywords: UHPLC, Phenolic acid, Solid phase extraction, Method development, Validation.