Determination of Phenolic Acids by a Modified HPLC: Its Application to Various Plant Materials

Abstract The determination of certain phenolic acids employing a gradient HPLC method is described, in this study. The analysis was performed by using a gradient program with the two solvents system (A: methanol:water:formic acid (10∶88∶2 v/v); B: methanol:water:formic acid (90:8:2 v/v)). The flow rate of 1 mL · min−1, injection volume of 10 µL was used and signals were detected at 280 nm. Propylparaben was a suitable compound as an internal standard for this system. The method was validated and highly repeatable (between RSD values of 0.35–1.65) and linear results were obtained. The LOD and LOQ values of the phenolic acids are in the range of (2.58×10−6−9.69×10−6 M) and (7.83×10−6−2.93×10−5 M), respectively. The applicability of the method was tested by using some plant source materials, and the phenolic acid contents were successfully determined via well‐defined peaks. Therefore, the progressed method is suggested for the quantification of phenolic acids in food industry and laboratories.