青霉噻唑酸表面分子印迹聚合物的制备及其吸附性能的考察

摘要

针对青霉素药物及乳制品中致敏杂质青霉噻唑酸（ PEOA）的特异性分离分析，采用表面印迹聚合法，以青霉噻唑酸为模板分子，制备青霉噻唑酸分子印迹聚合物（ PEOA⁃MIPs）。通过静态吸附、吸附动力学及选择性实验考察其吸附性能，结果显示PEOA⁃MIPs对青霉噻唑酸有特异的识别能力和快速的传质速率，饱和吸附量为122�78 mg／g，静态吸附和吸附速率分别符合Langmuir模型和准二级动力学方程，表明MIPs的吸附是以化学吸附为主的单分子层吸附。利用扫描电镜（ SEM）、红外光谱（ FT⁃IR）和热重分析（ TGA）对聚合物进行表征，结果显示聚合物成功接枝在硅胶表面，并具有良好的热稳定性。 PEOA⁃MIPs对PEOA具有特异的识别能力，可用作萃取介质，为建立快速分离分析致敏杂质青霉噻唑酸的方法提供基础。%On account of the specificity and reproducibility for the determination of penicilloic acid in penicillin, this study aims to prepare penicilloic acid imprinted polymers ( PEOA⁃MIPs) by surface polymerization method at the surface of modified silica particles by using penicilloic acid ( PEOA) as the template molecule, methacrylic acid ( MAA) as the functional monomer, ethylene glycol dimethacrylate ( EGDMA) as the cross linker, and methanol/acetonitrile as the solvents. The synthesis conditions were optimized, and PEOA⁃MIPs had the best adsorption capacity when the molar ratio of template molecule/functional monomer was 1∶4, cross linking degree was 85% and the solvent ratio of methanol/acetonitrile was 1∶1 ( v/v) . The adsorption properties were evaluated by adsorption experiments, including the adsorption isotherms, kinetics and selectivity. The adsorption process between PEOA⁃MIPs and PEOA fitted the Lang⁃muir adsorption isotherm with the maximum adsorption capacity of 122�78 mg/g and the pseu⁃do⁃second⁃order reaction kinetics with fast adsorption kinetics ( the equilibrium time of 45 min) . The as⁃synthesized PEOA⁃MIPs were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy ( FT⁃IR), and thermal gravimetric analysis ( TGA) . The results indicated that the MIPs layer has been successfully grafted on the surface of SiO2 microparticles and the PEOA⁃MIPs had the excellent thermal stability. The PEOA⁃MIPs showed the highest selective recognition for PEOA. The PEOA⁃MIPs possess a high adsorption capacity, rapid mass⁃transfer rate and high selectivity to PEOA when compared with non⁃imprinted polymers ( PEOA⁃NIPs) . The PEOA⁃MIPs was expected to be used as the solid phase extraction medium and this study provides the potential applications for fast recognition and analysis of the penicilloic acid in penicillin.