Simple determination of aflatoxins in rice by ultra-high performance liquid chromatography coupled to chemical post-column derivatization and fluorescence detection

A fast and simple analytical method was developed and characterized for the determination of aflatoxins (B-1, B-2, G(1) and G(2)) in rice. The procedure is based on a simple solid-liquid extraction without further clean-up, and analysis by ultra-high performance liquid chromatography coupled with fluorescence detection. Fluorescence emission of aflatoxins B-1 and G(1) was enhanced by post-column chemical derivatization using pyridinium bromide perbromide. The analytical method was satisfactorily characterized in white and brown rice. Under optimum conditions, external calibration in solvent could be used for quantification purposes and limits of quantification were below the maximum contents established by the European Union regulation for these contaminants/commodity group combination (0.07-0.14 mu g/kg for white rice and 0.20-0.28 mu g/kg for brown rice). Recovery studies carried out at three different concentration levels (0.5, 2 and 5 mu g/kg) showed values in the range of 84.5-105.3%, and RSDs= 5%.