Separation And Determination Of Uranium Based On Imprinted Polymer And Double-receptor Sandwich Supramolecule

In the introductory part of this paper, it is explained about the significance ofstudying new methods of separating and determining uranium based on imprintedpolymer and double-receptor sandwich supramolecule. Salophen complexes andmolecular imprinting technique as well as their development are also introduced. Thenthe research development in the separation and determination of uranium are reviewed.In the second chapter the synthesis and properties study of uranyl-salophenimprinted polymer is described. A new type of imprinted polymer for the selectiveseparation of uranyl from aqueous solution was prepared by using a complex of uranyl astemplate. Firstly salophen which is a tetradentate ligand of uranyl was synthesizedthrough the reaction of5-chloromethyl-2-hydroxybenzaldehyd with3,4-diaminobenzoicacid. Then the salophen was reacted with uranyl to form the complex uranyl-salophen.Finally the imprinted polymer was synthesized by using methyl methacrylate asfunctional monomer, ethylene glycol dimethacrylate as cross-linking agent anduranyl-salophen as template. The uranyl ion was removed from the polymer via acidleaching. The adsorption property and selective recognition ability of the polymer werestudied by equilibrium-adsorption method. The influence of experimental conditions tothe adsorption property was also investigated. The results show that in the presence ofcompetitor metal ions, the selectivity coefficients of uranyl for the imprinted polymer areover200, and the polymer could be used repeatedly.In the third chapter, a double–receptor sandwich supramolecule method for theseparation and determination of trace uranium is proposed. One receptor is a salophenwhich can react with uranyl to form a uranyl-salophen complex, and another receptor isan oligonucleotide which can bind uranyl to form oligonucleotide-uranyl-salophensupramolecule. The salophen was immobilized on the surface of silica gel particles andused as the solid phase receptor for separating uranium from solution. Theoligonucleotide was labeled with a fluorescent group and used as the labeled receptor forquantitatively analyzing uranium. In the procedure of separation and determination, uranyl ion was first combined with the solid phase receptor and then conjugated with thelabeled receptor to form the sandwich-type supramolecule. The labeled receptor in thesandwich supramolecule was then eluted and determined by fluorescence analysis. Theexperimental results demonstrate that this method has a number of advantages such ashigh selectivity, excellent pre-concentration capability, high sensitivity, good stability andlow cost. Under optimal conditions, the linear range for the detection of uranium is0.5to30.0ng/mL with a detection limit of0.2ng/mL. The proposed method was successfullyapplied for the separation and determination of uranium in real samples with therecoveries of95.0to105.5%.