Separation and identification of isoflavonoids in Pueraria lobata extracts and its preparations by reversed-phase capillary liquid chromatography coupled with electrospray ionization quadrupole time of flight mass spectrometry
Tian, H.; Wang, H.; Guan, Y.
Se Pu 23(5): 477-481
2005
ISSN/ISBN: 1000-8713 PMID: 16350789 Document Number: 587246
Isoflavonoids in Pueraria lobata extract and its preparations were separated and identified by reversed-phase capillary liquid chromatography (RP-CapLC) coupled with photodiode array (PDA) detector and negative electrospray ionization quadrupole time of flight (Q-TOF) mass spectrometry. The separation was performed on a 150 mm x 0. 32 mm i. d. , 5 microm C18 capillary column, using mobile phase of 0.1% aqueous trifluoroacetic acid solution and acetonitrile containing 0.1% trifluoroacetic acid under gradient elution. The product ion spectra of the deprotonated ions allowed for the identification of puerarin, daidzin and daidzein in the sample. Puerarin was found to be the most abundant component in the extract (about 13%, mass fraction) and its preparations (19.28 - 24.34 mg per tablet). The structures of trace amount of unknown isoflavonoids were deduced based on the spectra of known compounds. They were proposed to be 3'-methoxypuerarin and 3'-methoxydaidzin.