Abstract: This work investigated the suitability of applying fully 13C isotope labeled mycotoxins as internal standards for the accurate determination of 16 mycotoxins in maize and wheat by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The target analytes in samples were extracted, diluted, and detected by UPLC-MS/MS after addition of internal standards. The results showed that all 16 mycotoxins displayed good linear relationships with correlation coefficients more than 0.997. Recoveries of the analytes were in the range of 83%–114.3% with relative standard deviations of 0.9%–13%. The limits of quantification (LOQs) of the method ranged from 0.5 to 200 μg/kg. Maize reference materials, and corn and wheat samples were analyzed by this method to validate its accuracy and applicability. The method could accurately, quickly detect 16 mycotoxins in grains in batch.

Key words: direct dilution, stable isotope dilution, ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), mycotoxins, grains