| Polybrominated diphenyl ethers ?PBDEs? are a type of widely used flame retardant, which is a highly toxic, highly lipophilic, recalcitrance and bioaccumulative. In this study, targeting at 4, 4'-dibromodiphenyl ether, two kinds of novel functional monomers, in which the carbonyl in the carbamate group is used as "sacrifice group", were designed and synthesized based on the combination of the template substitution and "sacrifice spacer" strategies. Specifically, for the template without active hydrogen atom, such as 4,4'-dibromodiphenyl ether, the modified "sacrificing spacer" strategy was proposed by combining template substitution.4, 4'-Dibromodiphenyl amine with active hydrogen, whose chemical structure and size are similar as 4, 4'-dibromodiphenyl ether as target molecule, was used as the substitution template for imprinting. The carbamate as a couple bonding was formed via a nucleophilic substituted reaction. The recognition sites meet the demands of "sacrifice spacer" approach after removing the substituted template, which could selectively recognize 4,4'-dibromodiphenyl ether. The details are as follows.1. First, based on the aforementioned design and synthesis idea,4-vinylphenyl bis?4-bromophenyl? carbamate has been synthesized and polymerized by radical mechanism followed by cross-linking for the first time. The cross-linked poly?4-vinylphenyl bis?4-bromophenyl? carbamate? was hydrolyzed to remove the substituted template, and then the molecularly imprinted polymer ?VPBBPC-MIP? was obtained. The monomer, cross-linked polymer and molecularly imprinted polymer above-mentioned were characterized by FT-IR, NMR, GPC, TG and so on. Next, the isothermal adsorption, adsorption kinetics, competitive adsorption and repeat utilization tests were carried out and the recognition performances for MIP-VPBBPC were investigated. The experimental results indicated that MIP had an equilibrium adsorption capacity at 21.35 ? mol g-1, and it had strong recognition ability with an imprinting factor of 4.07 compared with non-molecularly imprinted polymer ?VP-NIP?, respectively. The adsorption processes of VPBBPC-MIP could be preferably described by Freundlich adsorption isotherm model. The kinetics study showed that the pseudo-second-order dynamic model could fit the adsorption process well. They had strong recognition abillity with an imprinting factor of 4.07 with VP-NIP. TheVPBBPC-MIP had very good repeatability and high reproducibility. Finally, the VPBBPC-MIP was used to determinate the 4,4'-dibromodiphenyl ether in water samples, and the absorption rates of the MIP was 94.07%.2. A novel amperometric electrochemical sensor was designed and prepared based on the template substitution and "sacrifice spacer" strategy for 4,4'-dibromodiphenyl ether detection. In this study, an amperometric sensor based on molecularly imprinted polymer ?MIP? was constructed for the first time. The sensor was prepared by electropolymerizing 2-acetamidophenyl bis?4-bromophenyl? carbamate on a indium-tin oxide ?ITO? glass, and then removing template by immersing poly [2-acetamidophenyl bis?4-bromophenyl? carbamate] film-coated ITO in ethanol. The molecularly imprinted sensor was characterized in the presence or absence of 4, 4'-dibromodiphenyl amine by cyclic voltammetry ?CV? and linear sweep voltammetry ?LSV? to verify the changes in the redox peak currents of potassium ferricyanide. The sensor responded sensitively to 4,4'-dibromodiphenyl ether over a linear range of 0.1 to 5 ?M with a detection limit of 1.6 uM. This molecularly imprinted sensor for the determination of 4,4'-dibromodiphenyl ether has high sensitivity, good selectivity and reproducibility and was applied to the determination of 4, 4'-dibromodiphenyl ether in amples. |
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