An amino-functionalized zirconium-based metal-organic framework of type UiO-66-NH₂ covered with a molecularly imprinted polymer as a sorbent for the extraction of aflatoxins AFB1, AFB2, AFG1 and AFG2 from grain

A surface imprinted polymer of type UiO-66-NH2@MIP was prepared by combining molecular imprinted polymers (MIPs) and an amino-functionalized zirconium-based metal-organic framework. Quercetin is used as the virtual template, UiO-66-NH₂ acts as the carrier to which the monomer acrylamide can be copolymerized. The material was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. It was used as a sorbent in a solid-phase extraction column. The extraction conditions were optimized. The adsorption capacities for aflatoxins AFB1, AFB2, AFG1 and AFG2 by this SPE and by the commercial SPE were compared. The method was successfully applied to quantify the aflatoxins in grain. Figures of merit include (a) good linearity (range from 0.20–45 μg·kg⁻¹) with R² (range from 0.9986–0.9994), (b) low detection limits (90–130 ng·kg⁻¹), (c) acceptable reproducibility (1.0–5.9%; for n = 6), and (d) relatively satisfactory recovery rates (74.3–98.6%). The new sorbent has good selectivity and reusability.