Simultaneous Determination of Six Compounds in the Gumiganghwal-tang by HPLC Coupled with DAD and ESI-MS.

Gumiganghwal-tang has been used for the treatment of the common cold for a long-time. We developed and validated an accurate and sensitive high performance liquid chromatography-diode array detection (HPLC-DAD) and electrospray ionization mass spectrometry (ESI-MS) for simultaneous determination of Imperatorin, ferulic acid, baicalin, glycyrrhizin, catalpol and oxypeucedanin in Gumiganghwal-tang. Six compounds were qualitatively identified based on their mass spectra and by comparison with standard compounds using HPLC-DAD. The analytes were separated on a LUNA C18 column (S-5µm, 4.6mm I.D.×250mm) with gradient elution composed of acetonitrile and 0.1% trifluoroacetic acid (TFA). All calibration curves showed good linear regression. The limits of detection (LOD) and the limits of quantification (LOQ) ranged from 0.22 to 0.45 and 0.66 to 1.24 µg/ml, respectively. Intra- and inter- day variation of this method were less than 2.88%. The mean recoveries evaluated were than 92.4%. The developed method has been successfully applied to the analysis of Gumiganghwal-tang.