Development and validation of an isocratic high-performance liquid chromatographic method for quantitative determination of phytoestrogens in soya bean

High-performance liquid chromatography (HPLC) is the technique most often used for the separation and quantification of phytoestrogens in various plants and food products. A number of HPLC methods using gradient elution have been developed for determination of phytoestrogens. These HPLC methods have been applied to the separation and quantification of phytoestrogens in various sample matrices. However, gradient elution methods are time consuming as they necessitate lengthy equilibration times and they require specialised pumps. This paper describes the development and validation of a reversed-phase HPLC method with isocratic conditions for the analysis of daidzein, genistein and biochanin A in soya beans using flavone as an internal standard. The proposed method has an overall elution time of about 24 min which compares well with elution times of 20-60 min for the gradient methods. Results for the linearity, sensitivity, precision and accuracy of the method are presented. (C) 1998 Elsevier Science B.V.