Preparation And Application Of Melamine Molecular Imprinting Adsorption And Separationmaterials

At present, the single-minded selective and specific identification molecular imprinting technique has been widely used in the food safety inspection, environmental samples testing and pesticide residues analysis, the effect was significant. In this paper, Melamine molecularly imprinted polymer (MIP) was prepared by bulk polymerization and two-step seed swelling polymerization method, respectively. Cyromazine molecularly imprinted polymer was prepared by bulk polymerization and two-step seed swelling polymerization method in aqueous system, too. The molecular imprinting testing technique for the detection of melamine in milk powder and for the detection of cyromazine in cucumber was established, respectively.The main contents included the following five areas:Chaper1Concept and application of the molecular imprinting technique (MIT) in the food safety inspection technology was introduced.1. Food security situation and the food safety testing technique introduction.2. Molecular imprinting technology, included:(1) Concept of molecular imprinting technology.(2) The principle of molecular imprinting technique.(3) Preparation of molecularly imprinted polymers.(4) Application of molecular imprinting technology in the food safety inspection.3. Molecularly imprinted solid phase exteaction technology.4. This paper studies the significance and contents.Chaper2Melamine molecularly imprinted polymers have been prepared using identical polymer formulation by both thermal-and photo-initiation method, respectively. The results showed that both thermal-and photo-induced polymers had the specific binding to melamine similarly, while the photo-induced polymers imprinting effect was more obvious. MIPs were used as selective sorbents for the solid phase extraction (SPE) of melamine from milk powders, followed by the determination using high performance liquid chromatography (HPLC). The mean recoveries of melamine in milk powders were obtained in the range of92.4%-97.7%(thermal-induced) and94.6%-99.7%(photo-induced), for both MIPs, respectively.Chaper3Melamine molecularly imprinted polymeric microspheres (MIPMs) were prepared by two-step seed swelling polymerization methods. Factors affecting the particle morphologies including emulsifier, dispersant, the water-oil ratio, and etc were optimized in order to obtain the MIPMs with a final narrow particle diameter of3-5μm. Characterization of the resulted polymeric microspheres were investigated by equilibrium binding experiments, scanning electron microscope (SEM), infrared absorption spectroscopy (IR), and mercury analyzer (MA), respectively. Application of the MIPMs as HPLC stationary phases detected the melamine in milk powder showed better imprinting effect. A linear calibration curve is obtained in the concentration range of0.5-20μg/mL (r=0.9991). The qualification limit was O.1μg/mL.Chaper4Cyromazine molecularly imprinted polymer (MIP) was synthesized by UV photo-initiation and bulk polymerization method at low temperature. Characterization of the resulted molecularly imprinted polymer was investigated by equilibrium binding experiments.Scatchard plot’s analysis displayed that the MIP on the cyromazine molecular adsorption sites was non-uniform and showed two different types of binding sites.The dissociation contents were Kd1=1.31μmol/L and Kd2=4.84μmol/L, the apparent maximum binding capacity were Qmax1=1.19μmol/g and Qmax2=2.46μmol/g, respectively. It was demonstrated that the proposed MISPE-HPLC method could be successfully applied to the determination of cyromazine in cucumber sample.The mean recoveries of cyromazine from cucumber were96.2-99.4%.Chaper5Cyromazine molecularly imprinted polymeric microspheres (MIPMs) were prepared by two-step seed swelling polymerization method in aqueous system. Factors affecting the particle morphologies including stirring rate, the porogen, and etc were optimized in order to obtain the MIPMs with a final narrow particle diameter of3-5μm. The specific adsorptivity of MIPMs were proved by equilibrium binding experiments, scanning electron microscope (SEM), infrared absorption spectroscopy (IR) and mercury analyzer (MA). Application of the MIPMs as HPLC stationary phases detected the cyromazine in cucumber showed better imprinting effect. A linear calibration curve was obtained in the concentration range of0.1-10μg/mL (r=0.9989). The qualification limit was0.02μg/mL. The results indicate that the method was faster, easier and sensitive.