RESUMEN
Objective To establish a method for determining the soybean isoflavones and Monacolin K in fermented soybean product by high performance liquid chromatography(HPLC). Methods The soybean isoflavones and Monacolin K in fermented soybean were separated by HPLC with polaris C18 (2.0 mm?100 mm, 3?m)at 50℃.The mixed solution of water (containing 0.3%phosphatic acid) and acetonitrile was used as mobile phase for gradient elution at a rate 0.30ml/min. And the absorption was measured at 260 nm, 237 nm for the soybean isoflavones and Monacolin K, were determined of soybean isoflavones and Monacolin K in fermented soybean product. Results When the contents of soybean isoflavones and Monacolin K were in 0.2～45mg/L, there was a good linear relationship between absorption and content, by which the average recoveries were 88.9%～101.1% and relative standard deviation ranged between 0.89%～3.19%. Conclusion The method is accurate and reliable for quantitative analysis of the soybean isoflavones and Monacolin K in fermented soybean product.