Determination of isoflavones in soybean product by HPLC

Two isoflavones in soybean product,genistein and daidzein,were determined by High performance liquid chromatography(HPLC).The soybean product was degreased by n-hexane at above 90℃ for 10 h,then extracted with 80% methanol at 80℃.Chromatographic separation conditions were: BDS Hypersil C18 column(250×4.6×5 mm),detection wavelength at 260 nm,column temperature at 35℃,gradient elution with a 1.0 ml/min flow rate,and a mobile phase containing methanol:(0.5%) acetic acid solution.