A comparative study of HPLC-DAD and UPLC-UV methods for simultaneous determination of 11 polyphenols in Moringa oleifera leaves

Abstract

Purpose: To develop, validate and compare two chromatographic methods - high performance liquid chromatography with diode array detector ((HPLC-DAD) and high performance liquid chromatography with ultraviolet detection (UPLC-UV) for the effective analysis of polyphenols in Moringa oleifera leaves. Methods: HPLC-DAD and UPLC-UV methods were applied for the accurate determination of eleven major polyphenols in Moringa oleifera leaves. The chromatographic conditions of the eleven polyphenols was determined on two C18 column by gradient elution with 0.5 % phosphoric acid solution -acetonitrile as the eluate, and at a flow rate of 1.0 and 0.5 mL/min for HPLC-DAD and UPLC-UV methods, respectively. Detector parameter of UPLC-UV was fixed at 203 nm. The assay methods were validated systematically. Results: The instrumental methods (HPLC-DAD and UPLC-UV) had good linearity, precision, repeatability and recovery. For both methods, quantification limits of UPLC-UV (0.057 - 0.363 μg/mL) were lower than those of UPLC-UV (0.094 - 1.532 μg/mL). The UPLC method with a shorter running time and more sensitive detection was applied in comparing to the HPLC method. After optimization and evaluation, the baseline of 11 compounds was separated effectively within 68 and 34 min, respectively. Conclusion: The developed HPLC-DAD and UPLC-UV assays were successfully utilized for the simultaneous analysis of eleven major polyphenols and can readily be utilized as quality control tools for Moringa oleifera leaves in China, with UPLC-UV method showing better separation, lower organic solvent usage and shorter analytical period.