LC-ESI-MS/MS, a modified method for simultaneous quantification of isoflavonoids, flavonoids, alkaloids and saponins in a Chinese herbal preparation Gegen-Qinlian decoction

A sensitive and reliable liquid chromatography-electrospray ionisation-tandem mass spectrometry (LC-ESI-MS/MS) method was established to simultaneously quantitate four categories of compounds (isoflavonoids, flavonoids, alkaloids and saponins) in Gegen-Qinlian decoction (GQD). These compounds were separated by a Shiseido CAPCELL PAK C18 column with a linear gradient consisting of 0.1% (v/v) formic acid in water (A) and 0.1% (v/v) formic acid in acetonitrile (B), and delivered at a flow rate of 0.3 mL/min. All the analytes were determined by electrospray positive ionization tandem mass spectrometry in a multiple reaction monitoring (MRM) mode. Linearity, accuracy, precision, recovery and stability of the method were evaluated with the validation over the range of 4.0-538 5 ng/mL. The proposed method was applied to the analysis of a Chinese herbal preparation GQD successfully.