HPLC with coulometric electrode array detection Determination of daidzein and genistein in soy based infant food, soy milk and soy based supplements

Abstract

A HPLC method coupled with coulometric electrode array detection for determination of daidzein and genistein in soy milk, soy-based infant food and nutritional supplements is described. The samples were spiked with bisphenol A (internal standard), extracted and hydrolyzed in an acid ethanolic solution. After purification of the extract on a C-18 cartridge the compounds were separated on a C-18 reversed phase column (50 mM sodium acetate adapted to pH 4.8 with glacial acetic acid/methanol at 450/550, v/v). The compounds were detected at eight electrodes set on potentials between +390 mV and +810 mV (in increments of 60 mV) against modified palladium electrodes. The contents of daidzein and genistein were determined in several commercial samples.