Quantitation of type B-trichothecene mycotoxins in foods and feeds by a multiple stable isotope dilution assay

For quantitation of the trichothecene mycotoxins deoxynivalenol (DON), 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol and 4-acetylnivalenol (Fusarenon X), stable isotope dilution assays (SIDAs) were developed by using analogues labelled with carbon-13 as the internal standards. The SIDAs presented here are the first ones reported for type B-trichothecenes. The synthesis of labelled acetyl derivatives was accomplished by [C-13(2)]-acetylation of unlabelled trichothecenes and subsequent hydrolysis of the products. The mycotoxins were quantified in foods by LC tandem MS after cleanup on multifunctional columns. The method revealed an excellent sensitivity with low detection and quantification limits for all mycotoxins in the low mu g/kg range, and good precision in inter-assay studies. The analysis of a certified reference material (maize flour) resulted in a low bias of 2.1% from the certified value for DON and verified excellent trueness of the new method. To prove the suitability of SIDA, a number of cereals and cereal products were analysed and revealed DON contents ranging from 2 to 300 mu g/kg. Acetylated derivatives occurred in lower contents and mainly in corn products.