Quantitation of Trichothecene Mycotoxins by Stable Isotope Dilution Assays

Abstract

Stable isotope dilution assays (SIDAs) for the simultaneous quantitation of type A and type B trichothecenes in cereal products were developed. Syntheses of [13C4]-diacetoxyscirpenol, [13C2]-monoacetoxyscirpenol, [13C4]-T-2 toxin, [13C2]-HT-2 toxin, [13C2]-3-acetyldeoxynivalenol, [13C2]-15-acetyldeoxynivalenol, and [13C2]-4-acetylnivalenol were accomplished by complete [13C2]-acetylation of T-2 triol, scirpentriol, deoxynivalenol, and nivalenol, respectively, followed by careful alkaline hydrolysis of the peracetylated compounds. Samples were spiked with the synthesized internal standards and purified on multifunctional columns. All trichothecenes under study were quantified simultaneously within one liquid chromatography (LC)-mass spectrometry (MS) run using single and tandem MS detection. The method revealed good sensitivity with low detection and quantification limits along with excellent recovery data and good precision in inter-assay studies. Food samples were analysed using the developed SIDA and showed substantial contamination of oat products with T-2 toxin and HT-2 toxin. Diacetoxyscirpenol was detected rarely and monoacetoxyscirpenol and 4-acetylnivalenol were not present in the analyzed samples. Further type B trichothecenes occurred more frequently and generally in higher concentrations than type A trichothecenes. The type B trichothecene deoxynivalenol was detectable in all cereal samples. Corn (maize) products did not only show the highest concentrations of deoxynivalenol, with values up to 300 μg/kg, but also distinct contamination with 15-acetyldeoxynivalenol, whereas 3-acetyldeoxynivalenol was predominantly found in oat products.