Accurate determination of type B trichothecenes and conjugated deoxynivalenol in grains by isotope dilution - liquid chromatography tandem mass spectrometry

An isotope dilution-liquid chromatography tandem mass spectrometry method (ID-LC/MS/MS) has been developed as a candidate reference method for the accurate measurement of major type B trichothecenes and conjugated deoxynivalenol mycotoxins in grain samples. C-13(15)-deoxynivalenol, C-13(15)-nivalenol, C-13(17)-3-acetyldeoxynivalenol, and C-13(17)-15-acetyldeoxynivalenol were used as internal standards, and the immunoaffinity columns and MycoSep 227 cartridges were employed for sample clean-up. The ID-LC/MS/MS method was validated by the analysis of samples fortified with the target mycotoxins at three concentration levels. The results exhibited sufficient accuracy of 98.2-102.6% with a relative expanded uncertainty of 1.3-3.8%. Moreover, the developed method was applied to the analysis of deoxynivalenol in the reference material and quality control samples (corn and wheat). Intraday and interday variations were also evaluated for the assessment of the metrological quality of the established method. This analytical method was proved to have a higher order metrological quality and exhibited greatly enhanced performance compared to other methods reported in literatures. Furthermore, the method will be applied to the value-assignment of certified reference materials that are under development in this laboratory.