Molecularly imprinted polymers hydrogel for the rapid risk-category-specific screening of food using SPE followed by fluorescence spectrometric detection

Current trends of functional monomers and cross linkers used to produce molecularly imprinted polymers for food analysis

Molecularly imprinted polymers (MIPs) as artificial synthetic receptors are in high demand for food analysis due to their inherent molecular recognition abilities. It is common practice to employ functional monomers with basic or acidic groups that can interact with analyte molecules via hydrogen bonds, covalent bonds, and other interactions (π-π, dipole-ion, hydrophobic, and Van der Waals). Therefore, selecting the appropriate functional monomer and cross-linker is crucial for determining how precisely they interact with the template and developing the polymeric network's three-dimensional structure. This study summarizes the advancements made in MIP's functional monomers and cross-linkers for food analysis from 2018 to 2023. The subsequent computational design of MIP has been thoroughly explained. The discussion has concluded with a look at the difficulties and prospects for MIP in food analysis.

Facile preparation of core-shell magnetic organic covalent framework via self-polymerization of two-in-one strategy as a magnetic solid-phase extraction adsorbent for determination of Rhodamine B in food samples

The monomer of two-in-one molecular design strategy (i.e., A₂B₂ type monomer) 1,6-bis(4-formylphenyl)-3,8-bis((4-aminophenyl) ethynyl)) pyrene (BFBAEPy) was self-polymerized and coated on the modified Fe₃O₄ surface to synthesize a magnetic covalent organic framework (Fe₃O₄@COF) nanocomposite with a core-shell structure. Before high-performance liquid chromatography with ultraviolet detection (HPLC-UV) determination, Fe₃O₄@COF was used as a magnetic solid-phase extraction (MSPE) adsorbent to enrich Rhodamine B (RhB) illegally added to Chili powder and Chinese prickly ash. It had a large specific surface area and suitable pore size, which promoted the efficient adsorption of RhB dye and eliminated the interference of the matrix. Several key parameters affecting the extraction recovery rate were investigated, including adsorption capacity, adsorption time, pH, ionic strength, elution solvent, elution volume and elution time. Under the best optimized conditions, within the linear detection range of 0.05-5 µg/mL for RhB with the limit of detection (LOD) was 0.0038 µg/mL, excellent linearity (correlation coefficient R²=0.9997), and good repeatability (relative standard deviations RSD%< 3.8%), satisfactory extraction recovery rate (91.7%-97.5%). Therefore, the application of the established method to the detection of RhB in food samples has bright prospects.