Determination of Soybean Isoflavones in Soybean Meal and Fermented Soybean Meal by Micella Electrokinetic Capillary Chromatography

OBJECTIVE To establish a micellar electrokinetic capillary chromatography(MECC) method for the determination of soybean isoflavones in soybean meal and fermented soybean meal.METHODS The separation was performed on a fused and uncoated silic capillary of 50 μm×60 cm(50 cm of effective length).10 mmol·L-1 sodium borate(pH 9.4) containing 15 mmol·L-1 sodium dodecyl sulfate(SDS) and 5% methanol was used as running buffer.Samples were injected hydrodynamically(5 s,3.0×103 Pa) into the capillary.The applied voltage was 17 kV and the wavelength of detection was set at 254 nm.The temperature was at 20 oC.RESULTS The six soybean isoflavones were completely isolated and showed good linear relationships.The average recoveries(n=5) were 99.6%-103.5% and RSDs were 1.8%-2.3% for daidzin,daidzein,genistin and genistein.CONCLUSION This method is accurate,reliable,economic,easy to operate and suitable for the determination of soybean isoflavones in soybean meal and fermented soybean meal.