Simultaneous determination of anemoside B4, phellodendrine, berberine, palmatine, obakunone, esculin, esculetin in rat plasma by UPLC-ESI-MS/MS and its application to a comparative pharmacokinetic study in normal and ulcerative colitis rats.A sensitive and rapid ultra-performance liquid chromatography-electrospray ionization-mass spectrometry (UPLC-ESI-MS/MS) method was developed for the simultaneous analysis of anemoside B4, phellodendrine, berberine, palmatine, obakunone, esculin, esculetin, toosendanin (IS1 of anemoside B4), tetrahydropalmatine (IS2 of phellodendrine, berberine, palmatine and obakunone) and scopoletin (IS3 of esculin and esculetin) and to compare the pharmacokinetics of these active ingredients in normal and ulcerative colitis rats. 
UPLC-ESI-MS/MS
Detection and measurement were performed on a 4000 QTRAP UPLC-MS/MS system from AB Sciex in the multiple reaction monitoring (MRM) mode. 
4000 QTRAP UPLC-MS/MS system from AB Sciex