Preparation Molecular Imprinted Polymer And Quantum Dots And Their Applications In Analytical Chemistry

With the rapid development of science and technology, analytical science isfacing the new opportunity and rigorous challenge. Sensitive, rapid, reproducible,simple and accurate analytical methods are required for the determination of tracecomponents in geological, biological and environmental samples. Although manyinstrument analysis methods possessing higher sensitivity and selectivity have beendeveloped recently, pre-concentration and analysis of trace elements is still necessarybefore the more accurate measurement by analytical instruments in reality. Thepre-concentration and analysis of trace elements will depend on different adsorptionmaterials with higher selectivity and larger adsorption capacity and appropriateseparation methods. In this research paper, several new adsorption materials aresynthesized in order to pre-concentration and separation of trace components. Theiradsorption and selectivity characteristics for trace components have been investigatedsystematically. The more detailed novelty of this research can be categorized asfollowing:1. A novel and simple imprinted amino-functionalized silica gel material wassynthesized by combining a surface molecular imprinting technique with a sol-gelprocess on the supporter of activated silica gel for solid-phase extraction-highperformance liquid chromatography (SPE-HPLC) determination of bisphenol A(BPA). The BPA-imprinted silica sorbent and non-imprinted silica sorbent werecharacterized by FT-IR and the static adsorption experiments. The preparedBPA-imprinted silica sorbent showed high adsorption capacity, significant selectivityand good site accessibility for BPA. Furthermore, the difference of the retentioncharacteristics of BPA on the C8 SPE column and BPA-imprinted silica SPE(MIP-SPE) was compared. The MIP-SPE-HPLC method showed higher selectivity toBPA than the traditional SPE-HPLC method. At last, the BPA-imprinted polymerswere used as the sorbent in solid-phase extraction to determine BPA in water samples. 2. A simple imprinted amino-functionalized silica gel material was synthesized bycombining a surface molecular imprinting technique with a sol-gel process forsolid-phase extraction-high performance liquid chromatography (SPE-HPLC)determination of diethylstilbestrol (DES). Activated silica gel was used as thesupporter and non-imprinted silica sorbent was synthesized without the addition ofDES using the same procedure as that of DES-imprinted silica sorbent. The maximumstatic adsorption capacity of the DES-imprinted and non-imprinted silica sorbent forDES was 62.58 mg g^-1 and 19.89 mg g^-1, respectively. The relatively selective factorvalue of this DES-imprinted silica sorbent was 61.7 at the level of 50 mg L^-1. And theuptake kinetics was fairly rapid so that the adsorbent equilibrium was achieved within10 min. Furthermore, the DES-imprinted polymers were used as the sorbent insolid-phase extraction to determine DES in fish samples.3. Molecularly imprinted bulk polymers (MIBs), prepared by bulk polymerizationand molecularly imprinted nanospheres (MINs), prepared by novel precipitationpolymerization method were synthesized in this work. The polymers were preparedwith diethylstilbestrol (DES) as the template molecule, methacrylic acid as thefunctional monomer and ethylene glycol dimethacrylate as the cross-linking monomerin the presence of acetonitrile solvent. The diameter of the MINs for DES wasapproximate 100 nm. These polymers were characterized by Fourier transforminfrared spectroscopy, transmission electron microscope and the static adsorptionexperiments. The prepared DES-imprinted nanospheres showed regularly shape andbetter adsorption capacity than DES-imprinted polymers.4. Three CaTe quantum dots were synthesized in an aqueous phase usingthioglycolic acid as capped reagent. TEM, FL and UV were used to characterize theshape and optical properties. Insulin and CdTe QDs were used to study the interactionof protein with QDs as model samples. Fluorescence spectroscopy was used toinvestigate the stoichiometry and thermodynamic parameters of interaction. Theresults showed that the fluorescence of CdTe was quenched by insulin. The quenchingmechanism was discussed to be a static quenching procedure. Moreover, based on theevaluation of association constant of various the ionic strength and pH value, we speculated that the interaction of CdTe with insulin was mainly due to electrostaticattraction.