[Identification of hydroxylate metabolites of daidzein and its sulfate conjugates in rat urine by LC-ESI/MS(n)].

Aim: To identify the hydroxylate metabolites and its sulfate conjugates of daidzein in rat urine.

Methods: Urine samples from 0 - 24 h were collected after single ig dose of 500 mg x kg(-1) daidzein to each of six rats. The urine samples were purified by SPE column (SPE C18) and analyzed with liquid chromatographic-tandem electrospray ionization ion trap mass spectrometry (LC-ESI/MS(n)) for potential metabolites.