Preparation And Performance Comparison Of Two Molecularly Imprinted Materials For Bisphenol A

Bisphenol A (BPA), a well known mimic estrogen which has endocrine-disrupting effects, has been wildly used in industrial manufacture. It can be released into the surface water and the groundwater. While the surface water is the most important water source of drinking water, the human beings under the risk of being direct or indirect exposed to BPA. Because it is widely distributed with low-doses, the analytical methods are based on expensive equipment such as HPLC, GC and other methods. But the solid-phase extraction used in these equipments has no selectivity while extracting the complex samples. To find a rapid, sensitive and selective specific adsorbents to separation and detection from complex samples for bisphenol A have been investigated from the environmental point of view.Molecularly imprinted polymer (MIPs) has generally chemical and heated-resistant. It can be used with HPLC as specific adsorbents to separate and detecte the low-doses target template in the samples. The size of MIPs is so small that they are difficult to recover for reuse. How to overcome the shortage becomes the problem need to be solved. Electrospinning can produce nano-fiber membrane, if this method can be directly used in preparation of molecularly imprinted polymers may overcome the disadvantages. Someone abroad had been prepared imprinted electrospinning membrane used for drug detection. However, the research on molecularly imprinted electrospinning membrane dealt with xenoestrogen such as BPA was not reported.In this paper, we prepared two molecularly imprinted materials of BPA, one is granular MIPs by precipitation polymerization and another is molecularly imprinted fiber membrane (MIFM) by electrospining. Then we compared their imprinting effects and identification performance in the water phase system. Using the polymer and membrane though off-line pre-treat the mixed solution, the selective recognition properties in mixed solution were analyzed with HPLC. The main results are as follows:The granular MIPs are prepared by precipitation polymerization, choosing methacrylic (MAA) or 4-vinylpyridine (4-Vpy) as functional monomers, divinylbenzene (DVB) or trimethylolpropane trimethacrylate (TRIM) as cross-linker. Finally make sure that take MAA as functional monomers, divinylbenzene as cross-linker prepared the best molecularly imprinted polymers. There are two recognition sites existed in MIPs, the maximum adsorption capacity was 221μmol/g in low concentrations of BPA solution, the maximum adsorption capacity was 606.9μmol/g when treatment with high concentrations of BPA solution. The imprinting factor of MIPs was 4.03.We optimized the electrospining condition of preparaing MIFM. In order to keep a certain rigid of fibers, we chose polysulfone, which has benzene ring structure, as matrix material. The effects of different dosage of template to imprinted molecule on adsorption properties of fibers were investigated. The maximum adsorption capacity of MIFM was 65.6μmol/g in low concentrations of BPA solution, while the maximum adsorption capacity of MIFM was 462μmol/g in high concentrations of BPA solution. The imprinting factor of MIPs was 2.26.After the MIPs or MIFM had been directly pre-treated by BPA and its analogues mixture solution, the imprinting effects and selectivity of the molecularly imprinted materials were measured with HPLC. The result is that the MIPs was better than MIFM.The cost analysis of the two molecularly imprinted materials was conducted from raw materials and preparation progresses, respectively. We find that the cost of electrospinning is lower than that of precipitation polymerization. Therefore, low concentrations of BPA solution can be treated by electrospinning MIFM, while the MIPs prepared by precipitation polymerization can be applied in high concentrations of BPA solution.