An accurate and simple analysis method by high-performance liquid chromatography (HPLC)-electrospray tandem mass spectrometry (ESI-MS-MS) for the ethanol extract of Corydalis yanhusuo was established in this study. In this method, a C(18) column was used, and the mobile phase was water (0.2% acetic acid, 0.1% triethylamine, v/v)-acetonitrile (24:76, v/v). Under the optimal analysis conditions established in this study, eight protoberberine quaternary alkaloids in the ethanol extract of Corydalis yanhusuo were well separated and identified, respectively. Eight regression equations showed a good linear relationship between the peak area of each marker and concentration (r = 0.9990-0.9995). The various other aspects of analysis (i.e., peak purity, precision, recovery, and repeatability) were also validated. For the eight components, the recoveries were found to be 98.9%, 99.2%, 105.0%, 97.7%, 101.4%, 98.6%, 98.5%, and 98.7%, respectively. The limits of detection were 14.6, 42.5, 22.4, 17.9, 25.4, 10.0, 18.7, 3.9 ng/mL, respectively, and the limits of quantitation were 48.6, 141.7, 74.6, 59.6, 84.8, 33.2, 62.3, and 12.9 ng/mL, respectively. The developed method is useful for the simultaneous determination of these alkaloids in a large number of ethanol extracts of Corydalis yanhusuo.
