Derivatization reactions for the determination of aflatoxins by liquid chromatography with fluorescence detection

Various derivatization methods for the fluorometric detection of aflatoxins after separation by HPLC are reviewed. In normal-phase chromatography the sensitivity for aflatoxins B1 and B2 was improved by using special mobile phases or a flow cell packed with silica-gel particles. In the nowadays more popular reversed-phase methods, the fluorescence intensity of B1 and G1 can be increased by precolumn derivatization with trifluoroacetic acid or by postcolumn derivatization with iodine or bromine. Optimum conditions for the reactions are discussed. In terms of sensitivity, the three derivatization schemes give similar results. The methods are compared with respect to experimental convenience, selectivity, reproducibility and suitability for automation.