Preparation Of EGCG Imprinted Polymers And Its Application In Electrochemical Sensor

This thesis is mainly composed of the following three sections:Firstly, EGCG-molecularly imprinted membrane was prepared using natural biopolymer chitosan (CS) as a functional monomer, PEG as porogen, and EGCG as a template molecule. The effects of adsorption time, pH, temperature, the ratio between functional monomer and template molecules were discussed. The morphologies of imprinted membrane was different from non-imprinted membrane according to the scanning electron (SEM) and atomic force microscope (AFM); Meanwhile, FTIR characterization confirmed that the template molecules were fully eluted. Scatchard analysis suggested that there was a class of binding sites during the molecularly imprinted membrane recognizing EGCG, and the max adsorption capacity of imprinted membrane and equilibrium binding constant arrive at49.5mg/g,1.376mg·L-1, respectivelySecondly, the sensor of EGCG was constructed based on the molecularly imprinting technique, CS as functional monomer, EGCG as template molecule. The EGCG imprinting sensitive film was coated to glassy carbon electrode through the electro-polymerization. And it was characterized by SEM and electrochemical analysis. The results showed that the imprinted electrode was significantly different from the non-imprinted electrode in morphologies and electrochemical properties, and a linear relationship between the decrease of peak current and the EGCG concentration was found in the range of6.0×10-5～1.4×10-4mol·L-1with a detection limit of7.8×10-7mol·L-1. Moreover, the imprinted electrode exhibits a good selectivity, anti-interference performance and rapid response to template molecules, as well as an excellent reproducibility (RSD=1.21%). Besides, it was found that the EGCG concentration in Tie Guan Yin was highest in three kinds of different areas tea, and the sensor was expected to fast and exactly detection for tea.Last, EGCG imprinted β-CD was prepared by using β-CD as functional monomer and HMDI as crossing linker. The factors including adsorption time and the ratio of functional monomer and template molecules to adsorption capacity was discussed, and characterized by means of SEM and FT-IR. The study confirmed that the imprinted polymers exhibited a class of binding site during the MIPs recognized EGCG, high selectivity and binding ability. Scatchard analysis of the imprinted polymers suggested that the max adsorption capacity of imprinted polymers and equilibrium binding constant arrive at112.5mg·g-1, K=112.9mg·L-1, respectively.