Abstract: A reverse-phase high performance liquid chromatographic method was established for the determination of daidzein and genistein. Waters Spherisorb? ODS2 column(4.6mm i.d.× 150mm, 5μ m) was used with a mixture of methanol- water (60:40, V/V) as the mobile phase and a detector set at 254nm. The calibration curve was linear(r=0.9984, p< 0.01) in the range of 0.05～20μg/ml of dadizein and was also linear(r=0.9978, p< 0.01) in the range of 0.05～10μg/ml of genistein. The recoveries of dadidzein and genistein were 91.72%～98.56% and 96.80%～98.60% respectively with the intra-day and inter-day RSDs of 1.30%、5.30% and 1.17%、3.84%, respectively. The pretreatment methods of different bio-samples were compared. It was found that ultrasonic treatment was the best among the three methods.

Key words: daidzein, genistein, RP-HPLC, yolk, feed stuff