The Studies Of The Chemical And Biologic Sensors Based On Prussian Blue/Chitosan Modified

The development of the chemical modified electrodes by insoluble metal hexacy- anoferrates such as Prussian Blue (PB) received the most attention for their remarkable stabilities and good chemical and electrocatalytic properties. This technology is now widely applied in many areas such as electrocatalysis, electro-chromatic devices, energy storage, ion recognition, biosensor and so on.The biopolymer chitosan(CS) is a kind of matrix for enzyme immobilization with attractive properties that include excellent film-forming ability, high permeability toward water, good adhesion, nontoxicity, and biocompatibility. Chitosan was utilized to improve the analytical performance of pure PB-modified electrode because of its unusual combinational property. This thesis systematically investigated the preparation of PB/CS modified electrodes, affecting factors and its electrochemical properties and applications. The physical and chemical properties of PB/CS film modified electrode were investigated extensively by some electrochemical techniques such as Cyclic Voltammetry, FI-IR and AC Impedance.The electrodeposited Chitosan/Prussian Blue hybridized films on gold electrode has the favorable electron transfer activity and the electrical catalysis for H2O2 and it also provides a hydrophilic matrix for embedding the biomolecules. The AC impedance spectrum was applied for study of more detailed kinetic and structural information. The experimental results have revealed that the optimal condition for deposition of PB/CS film is in complete accord with the research of cyclic voltammetry. The reason of this phenomena was explained by the further discussion based on those results. By the Randles simulation, the relative electrochemical parameters of the PB/CS film have been estimate for Rs=100.3?, Rct=2905?, ZCPE=5.56μF and the thickness for 80.63nm. The PB/ CS electrode is more stable than that of PB in pH=7-8 solution with faster electron transfer rate and has the excellent response on H2O2. A linear calibration plot was obtained in the wide concentration range from 1×10-6- 5×10-3mol/L.In this thesis, an amperometric glucose biosensor has been prepared by electrodeposition of glucose oxidase on Prussian blue-chitosan hybrid modified film with a gold basal electrode, where the hybrid film acts as the electron transfer mediator and also the matrix for immobilization of enzyme. The biosensor could respond glucose due to the excellent electrochemical catalysis of Prussian blue for reduction of hydrogen peroxide. The related experimental conditions for preparation and characterization of biosensor also have been studied in detail. The results showed that the optimum detection potential was 0.05V (vs. SCE) and the optimum pH was 6.0. Under selective conditions, the biosensor had a linear detection limit of 3.78×10-6mol/L(S/N=3) and the response time about 2.5s.