[关键词]
[摘要]
采用沉淀聚合法制备苯并咪唑类杀菌剂的分子印迹聚合物,以其共有的母核2-氨基苯并咪唑(AMB)为模板分子,采用Gaussian软件结合核磁共振氢谱对预聚体系进行筛选,确定功能单体的种类、比例和致孔溶剂种类,通过正交试验优化分子印迹聚合物(MIPs)的最佳制备条件。采用扫描电镜、比表面积及孔隙分析仪、红外光谱仪、热重分析仪以及吸附实验对聚合物进行结构表征和吸附性能研究。基于计算机分子模拟与核磁波谱手段筛选的预聚体系为AMB-衣康酸(IA)摩尔比1:2,致孔溶剂为乙腈。通过正交试验确定了MIPs的最佳制备条件。最优条件下制备的MIPs具有良好的热稳定性,对多菌灵(CBZ)的动态吸附平衡时间为120 min,吸附过程符合二级动力学反应模型。MIPs对CBZ的静态平衡吸附量Q为8.87 mg/g,印迹因子IF为2.89。Scatchard方程分析表明MIPs存在两类吸附位点。MIPs不仅对CBZ具有良好的吸附性,对其它苯并咪唑类杀菌剂噻菌灵、阿苯达唑和苯菌灵也具有较好的吸附性。该方法合成的MIPs作为固相萃取填料对石斛多糖提取液中四种苯并咪唑类杀菌剂的脱除率均达92%以上,总糖的损失率为14.94%。
[Key word]
[Abstract]
Molecularly imprinted polymers (MIPs) of benzimidazole fungicides were synthesized by the precipitation polymerization method. The common maternal nucleus, 2-aminobenzimidazole (AMB), was selected as template molecule, Gaussian 09W molecular modelling software and H-NMR were involved to determine types and proportions of functional monomers and types of solvents in preassembled system. The optimum preparation conditions of MIPs were optimized through orthogonal experiment design. Under optimal conditions, structural characterization and adsorption properties of MIPs were studied by scanning electron microscopy (SEM), brunauer-emmett-teller (BET), fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analyser (TGA) and adsorption experiment. According to computer molecular simulation and nuclear magnetic spectral analysis, itaconic acid (IA) and acetonitrile were selected as function monomer and solvent, respectively. The molar ratio of AMB and IA was determined as 1:2. Based on the above results, the optimum imprinting conditions were established through orthogonal experiments. MIPs were prepared under the above mentioned preparation conditions, indicating a good thermal stability. The results of dynamic adsorption experiments showed that the adsorption process of MIPs to carbendazim (CBZ) conformed to the pseudo-second-order kinetic model, and the adsorption equilibrium time was 120 min. The equilibrium adsorption capacity (Q) of CBZ was 8.87 mg/g, and the imprinting factor (IF) was 2.89. The Scatchard analysis showed that MIPs had two classes of adsorption sites. MIPs showed good adsorbability not only to CBZ, but also to other benzimidazole fungicides such as thiamidazim, albendazole and benzimidazim. The MIPs synthesized by this method were used as solid-phase extraction fillers to remove the benzimidazole fungicides in Dendrobium polysaccharide extract. The removal rates of four benzimidazole fungicides were higher than 92% and the loss rate of total sugar was 14.94%.
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[基金项目]
国家重点研发计划项目(2018YFC1602102-2);科技创新战略专项资金-高水平农科院建设(R2017YJ-YB2006;R2018QD-081)