A group of molecularly imprinted polymer (MIP) with specific molecule identification properties for norfloxacin (NFA) was prepared by precipitation polymerization using norfloxacin-Zn²⁺ as template molecule, ethyleneglycol dimethacrylant as the cross-linker, methacrylic acid and 4-vinyl pyridine as functional monomer respectively. The coordination proportion of the template molecule and functional monomer was studied by ultraviolet spectrum and the characterization of the molecularly imprinted polymer can be achieved by the infrared spectrum analysis. The result indicated that dominant induction imprinted complex with the ratio 1:1 was formed between norfloxacin-Zn²⁺ and methacrylic acid, while the dominant conjugation imprinted complex was formed by 4-vinyl pyridine as the functional monomer with the ratio of 1:2, and the ChemDraw pictures were used to display the imprinted form of the polymers. Then the scanning electron microscopy and the particle size distribution were used to characterize the physical properties of the molecularly imprinted polymer, the result showed irregular holes and porous scattered in the prepared molecularly imprinted polymer and the non-imprinted polymer surface was dense with no holes, then the particle size of the prepared polymer was less than 100 μm and the average particle size was 39 μm. The adsorption ability of the prepared polymer were researched by the isothermal combined experiment and the result revealed that the prepared molecularly imprinted polymer using 4-vinyl pyridine with the ring space structure as the functional monomer showed better selectivity recognition ability for norfloxacin than methacrylic acid with the chain structure, the specificity adsorption was 66.84 μmol/g and the imprinted index was 4.207, and it also showed better selective ability in the nofloxacin-Zn²⁺ and ofloxacin-Zn²⁺ mixture solution, the recognition factor was 3.408. Meanwhile the selective experiment displayed that the adsorption capacity of the non-imprinted polymer was small and closed to each other, therefore the recognition factor was close to 1, this indicated that the recognition ability of the non-imprinted polymer to the adsorption substrate was non selective.

Key words: norfloxacin-Zn²⁺, precipitation polymerization, metal coordination, induction, conjugation