Liquid chromatography-atmospheric pressure chemical ionization mass spectrometry as a tool for the characterization of anthraquinone derivatives from Chinese herbal medicine.

We have examined the anthraquinone derivatives of a Chinese herb medicine 'Rhubarb' by using HPLC/MS/MS, equipped with an atmospheric pressure chemical ionization source. The simultaneous determination of five ingredients in the sample extracts by HPLC/MS/MS was demonstrated. Product ion spectra of these components in the extracts were obtained and matched against known standards. Concentrations of these active ingredients were estimated by multiple reaction monitoring in the negative ion mode using a single HPLC run.