[Preparation of surface molecularly imprinted polymers for penicilloic acid, and its adsorption properties]

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 Langmuir adsorption isotherm with the maximum adsorption capacity of 122. 78 mg/g and the pseudo-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.