Analysis of isoflavonoids in Trifolium pratense L. by high performance liquid chromatography-electrospray ionization mass spectrometry

A high performance liquid chromatography-electrospray ionization-mass spectrometry was developed for the analysis and identification of isoflavonoids in Trifolium pratense L. Samples were analyzed by a reversed-phase C-18 column using a binary eluent under gradient conditions. Fourteen isoflavonoids could be separated and detected. The [M + H](+) ions of isoflavonoids in the positive mode were observed for molecule mass information. An in-source collision induced dissociation( in-source CID) experiment was carried out in order to identify the structure of isoflavonoids. The identified isoflavonoids were daidzin, pseudobaptigenin-7-O-beta-D-glucoside, ononin, irilone-4'-O-beta-D-glucoside, daidzein, sissotrin, prunetin-4'-O-beta-D-glucoside, genistein, pratensein, formononetin, prunetin, biochanin A, pseudobaptigenin and irilone.