Abstract: A simple and sensitive high performance liquid chromatography (HPLC) method was established for simultaneous determination of 5 phenolic acids (trans-cinnamic acid, p-coumaric acid, caffeic acid, ferulic acid and sinapic acid) involved in the lignin synthesis of harvested wax apple. The chromatographic separation was achieved using an InfinityLab Poroahell C18 column through gradient elution with a mobile phases consisting of methanol and acetic acid aqueous solution (pH 2.4) at a flow rate of 0.8 mL/min. The column temperature was set at 25 ℃. The detection wavelengths were set at 279 and 320 nm. The method exhibited a wide linear range with correlation coefficients all above 0.999 4. The limits of detection (LODs) were in the range of 0.01–0.03 mg/kg and the limits of quantitation (LOQs) were in the range of 0.03–0.09 mg/kg. The spiked recoveries ranged from 86.18%–99.05%, with relative standard deviations (RSDs) less than 5%. This method proved to be accurate, sensitive and simple and could be applied to determine the 5 phenolic acids in wax apple. The measured contents of trans-cinnamic acid, p-coumaric acid, caffeic acid, ferulic acid and sinapic acid were 11.46–24.69, 0.92–1.45, 2.31–5.32, 8.86–20.58 and 9.48–22.62 mg/kg in wax apple, respectively.

Key words: high performance liquid chromatography, wax apple, phenolic acid, lignin, determination method