Solid Phase Extraction Based on Covalent Organic Framework Hydrogel and Its Application in Pesticide Detection
Excessive pesticide residues in food pose a potential threat to biodiversity and human health.Solid phase extraction(SPE)technology is widely used in the extraction of pesticides,and the core of this method is the selection of adsorbent materials.Covalent organic frameworks(COFs)have attracted significant attention in sample pretreatment due to their unique advantages.The struc-ture of COFs determines the material's adsorption performance,which plays a crucial role in improv-ing pesticide extraction efficiency.In this study,six COFs with different structural properties(grafting different functional groups onto the same parent material,possessing different charged properties and conjugated structures)were prepared.To facilitate experimentation without altering the structure of the COFs,they were formulated into COFs-sodium alginate hydrogels(CACPs).A CACPs-dispersed solid-phase extraction(CACPs-dSPE)method was established to compare the ex-traction effects of different CACPs for carbamate,triazole,and triazine pesticides.Scanning elec-tron microscopy,Fourier transform infrared spectroscopy,X-ray crystal diffraction and other meth-ods were used to characterise the morphology,structures and properties of the series of COFs as well as the series of CACPs.The extraction effect was investigated by CACPs-dSPE combined with high performance liquid chromatography(HPLC)or ultra violet-visible spectrophotometry(U V-Vis).By combining theoretical calculations to simulate the binding of COFs with the analyte,this study ex-plores the adsorption mechanism of different CACPs on carbamate,triazole,and triazine pesti-cides.The results showed that the optimal adsorption performance of CACPs for different types of pes-ticides varied,which was coordinately determined by the nature of their porous structure(specific sur-face area,pore size)and the intrinsic structure of the loaded COFs(size of conjugated structure,grafted groups).The CACPs prepared by COFs with large conjugated structures and grafted hydroxyl groups were most favourable for the adsorption of three types of pesticides,with Dt-TAPB-CACPs showing the best extraction effect,providing theoretical guidance for the selection and design of ad-sorption materials in the process of pesticide extraction.
万方数据
维普
