Improved method for the simultaneous determination of aflatoxins, ochratoxin A and Fusarium toxins in cereals and derived products by liquid chromatography–tandem mass spectrometry after multi-toxin immunoaffinity clean up

Abstract

An improved method for the quantitative determination of aflatoxins (B1, B2, G1, G2), ochratoxin A, fumonisins (B1, B2), zearalenone, deoxynivalenol, nivalenol, T-2 and HT-2 toxins in cereals and derived products, at levels comparable with EU maximum permitted levels, was developed. The effective co-extraction of the mycotoxins under investigation was achieved in 4min by a double extraction approach, using water followed by methanol. Clean up of the extract was performed by a new multi-toxin immunoaffinity column. Analytical performance characteristics were evaluated through single laboratory validation. Raw wheat and maize, corn flakes and maize snacks were chosen as representative matrices for method validation. The validation assay was carried out at 50, 100 and 150% of EU maximum permitted levels for each mycotoxin. Statistical analysis of the results (ANOVA) provided the within laboratory reproducibility and the error contributions from repeatability, between day effects, and influences from different matrix composition. Recoveries generally higher than 70% were obtained for all tested mycotoxins with relative standard deviation (within laboratory reproducibility) lesser than 37%. Limits of quantification (calculated as the lowest amount of each analyte which could be determined with a precision of 10%) ranged from 1μg/kg to 30μg/kg. The trueness of generated data was assessed by analysis of reference materials. The proposed method was proven to be suitable to assess, with a single analysis, compliance of the selected cereal based foods with the EU maximum permitted or recommended levels for all regulated mycotoxins.