HPLC Method for Simultaneous Determination of Six Isoflavones in Soybean Yoghurt

Abstract Objective: To establish an HPLC method for simultaneous determination of six isoflavones (daidzin, glycitin, genistin, daidzein, glycitein, and genistein) in soybean yoghurt, providing a reference for its development of quality standards and functional evaluation. Methods: The six kinds of isoflavones were measured on a C18 column (250 mm×4.6 mm, 5μm) with a gradient solvent system of acetonitrile - trifluoroacetic acid solution as mobile phase at a flow rate of 1mL·mL-1 and the column temperature was kept at 40°C. The detection wavelength was 255nm. Results: Excellent chromatographic separation and good linearity with peak areas were achieved for 6 kinds of soybean isoflavones composition. The experiment was reproducible. Within the studied concentration ranges, the RSD were less than 2.50% and the average recovery were between 94.10% and 99.70%. Conclusion: This HPLC method is simple, feasible, stable and reliable. More importantly, it can detect the content of six soybean isoflavones simultaneously.