| As a kind of new functional materials in recent decades,Fe3O4 magnetic nano materials have been fully developed in many fields,especially in biomedical field in recent years,with the development of molecular imprinting technology,the combination of molecular imprinting technology and magnetic separation technology for the separation of trace pollutants in the environment detection drawed more and more attention of researchers.food packaging materials(especially for the type of polymer,such as PC、PE and PP),which directly contact with the food,was added bisphenol A in the actual production process in order to make it colorless,transparent,durable and lighter and outstanding characteristics such as protection of impact.as plasticizer,antioxidants and heat stabilizer,bisphenol A could migrate from packaging material or filtrate into food stuffs during the process of transportation and storage,which do harm to human health.Unfortunately,it is difficult to detect and separate BPA from environment because of its traces of distribution.at present,the pretreatment technology for detection of BPA mainly include solid phase extraction,liquid-liquid extraction,soxhlet extraction,etc.but these methods has some disadvantages,just as:more organic solvent、time consuming and lack of selective separation performance.so it is necessary to develop a fast and efficient technology,which with good recognition performance and can directly separate and enrich bisphenol A.An effective method of separating and enriching bisphenol A was developed in this paper,based on the combination of magnetic separation technology and molecular imprinting technology,and finally used in measuring the 9 most commonly used packaging materialsThe coprecipitation conditions of preparating nano ferroferric oxide was first optimized in this experiment,Using Single factor analysis,a best preparation project was determined at last throughing the observation and test of particle color,Settling velocity,particle size.The result shows that the optimal condition for preparation of Fe3O4 nanoparticles as following:molar ratio of Fe(Ⅱ)/Fe(Ⅲ)is 1:1.8,the mixing speed is 350rpm,reaction temperature is 50℃,curing a half hours under temperature 70 ℃,Reaction system pH is 10,In nitrogen atmosphere.Characterization results show that the Fe3O4 nanoparticles obtained are well-crystallized particles,with an average size of 15nm,which has good disprsivity and strong magnetic responsiveness,magnetic measurement reveals the magnetic nanoparticles are superparamagnetic with saturated magnetic intensity、remanence and coercive force are respectively 76.277 emu/g、2.3776 emu/g and 15.742 g.Bisphenol A molecularly imprinted polymers(Fe3O4@MIPS)were prepared by emulsion polymerization method using Fe3O4 magnetic particles as magnetic cores,then polymers were investigated by infrared ray diffraction spectrum(FT-IR),X-ray dfiffraction(XRD),transmission electron microscopy(TEM)and vibrating sample magnetometer(VSM)in order to elucidate the morphology,magnetic and other properties.the molecularly imprinted polymer adsorption performance on bisphenol A were also studied,the results of adsorption experiment indicated that the Fe3O4@MIPS have a much higer adsorbability than Fe3O4@NIPS,the Scatchard analysis results demonstrate that the maximum apparent adsorption quantity of bisphenol A on Fe3O4@MIPS is 126.44μmol/g,adsorption process reached balance in 25 hours.The magnetic polymer molecules was used in separating and enriching bisphenol A in actual samples,the results show that five samples have different levels of bisphenol A out of nine samples.PC material had the highest content of BPA,part of the PET and PP material also contain bisphenol A.Bisphenol A molecularly imprinted polymers can be used for all the enrichment of trace concentrations of BPA in food packaging and contact materials. |
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