Evaluation of a fluorometric–enzymatic method based on 3α-hydroxysteroid dehydrogenase for the mycotoxin zearalenone determination in corn

A new method for the fluorometric determination of zearalenone (ZEN) based on its reaction with βNADH in the presence of the enzyme 3α-hydroxysteroid dehydrogenase (3α-HSD) is described. The procedure is based on the change in fluorescence intensity that takes place during the enzymatic reaction (excitation at 340 nm and emission at 454 nm). The optimum reaction conditions and the analytical characteristics were studied; linear response range (1–10 mg l−1) and reproducibility (8 mg l−1, 2.7%, n=7). Moreover, a mathematical model explaining the analytical signal is proposed. The method has been applied to zearalenone determination in a spiked corn sample.