Hyphenated chromatographic techniques for structural characterization and determination of masked mycotoxins

Mycotoxins are secondary metabolites produced by fungi that can contaminate a wide range of food and feed commodities and that are harmful to humans for their poisonous and toxic effects. An increasing amount of data have been accumulated in the last years, showing that mycotoxins may also occur in modified forms originating by plant, fungi or animal metabolism or by food processing. In particular, this modified forms may be produced via conjugation with sugars or other biological components (masked mycotoxins) or may occur as non extractable forms on account of strong interaction, association or binding with macromolecules in the food matrix (bound or hidden mycotoxins). Analytical methods have been set up in order to check for the occurrence of these forms and to evaluate their amount, in order to obtain reliable data for toxicity and exposure studies. In this paper hyphenated chromatographic methods for the determination and structural characterization of masked mycotoxins are reviewed, with a particular emphasis on liquid chromatography–(tandem) mass spectrometry as the most effective approach for their determination.