A novel magnetic metal–organic framework absorbent for rapid detection of aflatoxins B1B2G1G2 in rice by HPLC-MS/MS

Abstract

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.