Rapid and Effective Sample Cleanup based on Polyvinylpyrrolidone-Coated Magnetite Nanoparticles Coupled with New Pre-Column Derivatization for Determination of Aflatoxins B1, B2, G1 and G2 in Animal Feeds by High-Performance Liquid Chromatography with Fluorescence Detection

A novel method for the determination of aflatoxins B1, B2, G1, and G2 (AFB1, AFB2, AFG1, AFG2) in animal feed samples based on magnetic solid-phase cleanup and novel pre-column derivatization has been developed. In this work, synthesized polyvinylpyrrolidone-coated Fe3O4 magnetic nanoparticles were applied as adsorbents for rapid cleanup for extracts of animal feed samples. The purified extract was then derivatized with trifluoroacetic acid coupling ultraviolet irradiation which enabled the weakly fluorescent AFB1 and AFG1 transformed into their highly fluorescent hemiacetals derivatives. Afterward aflatoxins were separated and quantified by reverse phase liquid chromatography with fluorescence detection. The results indicated that four AFs presented excellent linear response with correlation coefficients > 0.996 and recoveries ranged from 86.7 to 108.9% with relative standard deviations (RSDs) from 3.6 to 6.4%. The limits of detection (LODs) were 0.0392, 0.2429, 0.0842, 0.4556 ng mL-1 for AFB1, AFB2, AFG1 and AFG2, respectively.