Identification and determination of the major constituents in traditional Chinese medicine Si-Wu-Tang by HPLC coupled with DAD and ESI-MS.

An HPLC/DAD/ESI/MS method was established for the qualitative and quantitative analysis of the major constituents in Si-Wu-Tang, a traditional Chinese medicine formula. Based on the baseline chromatographic separation of most constituents in Si-Wu-Tang on hypersil C18 column with water-acetonitrile-acetic acid as mobile phase, 12 compounds including phenolic acids, phthalides and terpene glycoside were identified by online ESI-MS and the comparison with literature data and standard samples. Most of these compounds derive from Paeonia lactiflora and Ligusticum chuanxiong. Seven of them were quantitated by HPLC coupled with DAD. The validation of the method, including sensitivity, linearity, repeatability, recovery, were examined. The linear calibration curve were acquired with R2 > 0.99 and LOD (S/N = 3) were between 0.75 and 5 ng. The repeatability was evaluated by intra- and inter-day assays and R.S.D. value were within +/- 2.38%. The recovery rates of selected compounds were in the range of 96.64-105.21% with R.S.D. less than 3.22%.