Qualitative and quantitative analysis of flavonoids in the leaves of Isatis indigatica Fort. by ultra-performance liquid chromatography with PDA and electrospray ionization tandem mass spectrometry detection

A novel method based on ultra-performance liquid chromatography with photo diode array and electrospray ionization tandem mass spectrometry detection (UPLC-PDA-ESI-MS/MS) was developed for the qualitative and quantitative analysis of flavonoids in the leaves of Isatis indigotica Fort. (Daqingye). The separation was carried out on an Acquity UPLC BEH C-18 column with 0.1% formic acid and methanol as the mobile phase under gradient conditions. Eight flavone C-glucosides were identified and their mass spectrometric fragmentation patterns were studied. Among them, the fragmentation pathways of three flavone 6-C-diglucosides with the rare 1 -> 3 interglycosidic linkage were investigated for the first time. In addition, a quantitative analytical method for six flavone C-glucosides in Daqingye by UPLC-ESI-MS/MS was established and applied for the determination of commercial Daqingye samples from different resources. (C) 2008 Elsevier B.V. All rights reserved.