Optimization of matrix solid-phase dispersion extraction method for the analysis of isoflavones in Trifolium pratense

A method based on matrix sol id-phase dispersion (MSPD) has been developed for the determination of 12 isoflavones in Trifolium pratense L Dried leaf samples were blended with C-18, placed in small columns and isoflavones extracted with dichloromethane-methanol. Analyses were performed by high performance liquid chromatography with diode array detection (HPLC-DAD) with 2-methoxyflavone as internal standard. Several dispersants, eluents; and clean-up steps were tested during the optimization of the process in order to obtain the best selectivity and yields. Mean recoveries ranged from 70% to 119%, with relative standard deviations <18% The limits of detection were between 0.006 mg/l for biochanin A and 0.108 mg/l for daidzin. The performance of the optimized method in real samples was compared with a conventional method based in solid-liquid extraction (SLE). (C) 2009 Elsevier B.V. All rights reserved.