Quantitative and qualitative determination of Liuwei Dihuang tablets by HPLC-UV-MS-MS

A method is developed for the analysis of allantoin, gallic acid, dihydromelittoside, loganin, paeoniflorin, benzoylpaeoniflorin, and paeonol in Liuwei Dihuang tablets by high-performance liquid chromatography (HPLC)-UV-mass spectrometry (MS)-MS. Gradient elution with methanol-acetonitrile-water-formic acid solvent system is employed in the HPLC-electrospray ionization-MS study. The positive-ion ESI mode is suitable for these compounds. The peaks of gallic acid, loganin, dihydromelittoside, paeoniflorin, benzoylpaeoniflorin, and paeonol are identified by their mass spectra and the fragments of their MS-MS spectra. Allantoin, gallic acid, loganin, paeoniflorin, and paeonol are simultaneously determined by UV detection at 210 nm for quantitative purposes.