RESUMO
In this study, a core-shell-structured magnetic metal-organic framework (MMOF) composite material (Fe3O4@UiO-66-NH2) was synthesized by the solvothermal method. It was employed as a new absorbent in combination with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) for the simultaneous detection of four aflatoxins (AFs) in rice. This method could shorten the pre-processing time by exploiting the advantageous characteristics of magnetic cores. The impurity was removed quickly. The effects of extraction solution, extraction time, adsorbent types, and amount of adsorbent on the extraction rate of target compounds were optimized. Under optimized conditions, AFs were validated and showed a good linear relationship within the 0.375-20 µg kg-1 concentration range (r2 > 0.9992). The limit of detection (LOD) was 0.0188-0.1250 µg kg-1 and the limit of quantification (LOQ) was 0.0375-0.3750 µg kg-1. At three spiking levels (0.375, 2, and 10 µg kg-1), the average recovery values for the four AFs ranged from 85.1% to 111.0%. The relative standard deviation ranged from 3.4% to 7.7%. The new method proved to be simple, fast, efficient, and suitable for the determination of AFs in rice samples.
