Preparation And Application Of Molecularly Imprinted Polymer For Selective Recognition Of Polybrominated Diphenyls

Polybrominated biphenyls, as a kind of brominated flame retardants, have been widely used in ABS plastics, coatings, textiles and electronic products. Generally, polybrominated biphenyls are additive flame retardants lacking bound of chemical bond, easily release to environment from the product, which is harmful to human health. Research of U.S. Environmental Protection Agency has proved that polybrominated biphenyls can disturb the secretion of steroid hormone, affect the development of intelligence and even cause cancer. Now, it has been reported that polybrominated biphenyls were found at trace levels in various samples including oils, fish, vegetables and water. As the complexity of food matrix, it is necessary to establish a high selective and stable analytical technique with efficient sample pretreatment.In this study, a novel molecularly imprinted polymer with good selectivity and sensitivity to polybrominated biphenyls was prepared using3,3’,5,5’-tetramethylbenzidine as dummy template,3-mercaptopropyltrimethoxysilane as the monomer, and tetramethoxysilane as the cross-linker by surface molecular imprinting technique in combination with a sol-gel process. With a series of optimization experiments, it was found that the imprined polymer prepared with the solvent of N,N-dimethylformamide (2.0mL) and methanol (1.0mL), the amount of template molecule, functional monomer and cross-linker at0.3600g,0.836mL,0.443mL (molar ratio:1:3:2).1.00mL NH3·H2O (0.1mol L-1) as catalyst,50mL N.N-dimethylformamide and HCl(1.0mol·L-1)(1/1, v/v) as the elution solvent for removing the template, had higher adsorption capacity and selective ability for the template molecule. The results of adsorption experiments indicated that the imprinted polymer had fast mass transfer rate (the adsorption equilibrium was achieved in30min) and higher saturated adsorption capacity (7.54mg·g-1) to the template.A simultaneous determination method for six polybrominated biphenyls was developed using the prepared polymer as enrichment material by combining solid phase extraction with gas chromatography. Under the optimum conditions, the enrichment factors were between79.14and96.85. imprinting factor for six PBBs were over1.6. linear plots with R2>0.99were achieved over a range of0.01-5.0μg·L-1. The detection limit for each analytes was between2.0ng·L-1and8.0ng·L-1, relative standard deviation (RSD) for nine parallel determinations were below7.89%.To evaluate the applicability of the developed method, free samples of oils, fish, sea water, lake water and rural water from Yue Yang were spiked with three levels of polybrominated biphenyls (oils and fish:0.40μg·kg-1,2.0μg·kg-1,20μg·kg-1; water:0.02μg·L-1,0.1μg·L-1,1.0μg·L-1) and analyzed. Good recovery of six PBBs in these samples was achieved ranging from61.48%to114.06%with high precision of RSD less than9.73%.