ABSTRACT
By comparing with the molecule weights, retention times and product ion spectra of the standards, the cholic acid, deoxycholic acid and chenodeoxycholic acid were identified in the traditional Chinese compound medicine——“Qingkailing” injection by high performance liquid chromatography/mass spectrometry/mass spectrometry. Two other isomers of cholic acid and deoxycholic acid were also found, but tieir detail structure was still unknown due to the absence of standards. A quantitative method to determine cholic acid in the medicine was established and studied. An internal standard was used in quantitative analysis. When the concentration of cholic acid is from 875 ng/L to 140 μg/L, the chromatographic peak area and concentration are of good linear relation. The linear correlation coefficient was determined to be 0.9999 and the RSD is 2.04%. This method is simple, selective and highly sensitive, which is helpful for the quality control of traditional Chinese medicine.