Characterization of molecularly imprinted polymer particles specifically tailored for removal of trace 17beta-estradiol in water

Endocrine disturbing chemicals (EDCs) are a group of emerging contaminants that have been detected at trace concentrations in water around the world. Natural and synthetic hormones, (including estrogenic compounds) from the EDCs family in water and wastewater effluents have an adverse impact on ecology and human health. This poses a unique challenge for wastewater treatment plants (WWTP) intent on the analysis and removal of estrogenic compounds. During the last decade, research interest in molecularly imprinted polymer (MIP) particles has increased strongly. Chemical and mechanical stability together with high selectivity for the template analyte render MIPs an interesting alternative to routinely applied sorbent materials or antibodies.;CE characterization of MIP and NIP particles was investigated next. Electropherograms were successfully acquired for the six different MIP and NIP particles, and their electrophoretic mobilities were determined. Separation of MIP and NIP particles using 50 mM borate buffer (pH 8.5) containing 0.005% (w/v) EOTrol(TM) LN allowed CE for use in reverse polarity (-30 kV) as a simple and fast characterization technique. Dynamic light scattering (DLS) measurement of the sizes, together with the electrophoretic mobilities of MIP and NIP particles, allowed for an estimation of their surface charges. These charges were interpreted to represent the nonspecific binding properties of MIP in comparison with NIP particles. Instrumental limitation for injection of E2 (or other EDCs) and NIP particles in mixture set a lower limit (of ∼20 s) on allowable incubation time for non-specific binding kinetics study. Co-injection of bisphenol A (BPA, a model EDC) and E2 allowed a study on the selectivity of MIP particles, whereas the two compounds competed for available binding cavities. Moreover, it was confirmed that addition of E2 after BPA resulted in their occupation of the specific binding sites of MIP particles, displacing the BPA.;In summary, among the three types of synthesized MIP particles, MIP-T7 has a great potential for non-specific removal of EDCs, in addition to specific removal of E2. MIP-T7, with imprinting effect close to 3 and large binding capacity, showed the best binding properties. Investigative characterization of MIP and NIP particles established that CE and DLS could be used for a rapid determination of non-specific binding sites on submicron particles. Last, CE study on binding selectivity of MIP particles led to a better understanding of the binding mechanism between E2 and MIP particles.;This thesis consists of two main studies on the preparation of MIP particles specifically for 17beta-estradiol (E2), and the characterization of MIP particles using capillary electrophoresis (CE). Three types of MIP particles were synthesized, using either EGDMA (MIP-E) or TRIM (MIP-T4, MIP-T7) in two different mole ratios as a cross-linker. Binding efficiency of E2 on these MIP and non-imprinted polymer (NIP) particles were examined. Experimental results showed that after 2 min of incubation, 90+/-5% of E2 bound onto the particles. According to Scatchard analysis, an adsorption model containing two types of binding sites, namely specific and non-specific, was proposed. Further results indicated that the binding capacity of 8+/-3 mumol/g for MIP-E was increased significantly to 33+/-7 and 43+/-8 mumol/g for MIP-T4 and MIP-T7. Leakage tests, by high performance liquid chromatography with fluorescence detection (HPLC-FD), showed that bound E2 did not leak to the aqueous solution. The binding capacity, high binding efficiency of 96+/-3 % (after equilibrium) and no detectable leakage of bound E2 made these particles a great kind of sorbent materials for removal of E2 from water.