Fabrication And Application Of Three Kinds Of Protein Modified Electrodes

Due to their unique physical and chemical properties, nanomaterials, ionic liquids and their composite have already been a hot area in the fabrication of protein modified electrodes. In this thesis, three kinds of protein modified electrodes based on carbon ionic liquid electrode (CILE) and nanomaterials were prepared. The direct electrochemistry of myoglobin (Mb) and hemoglobin (Hb) were studied and the new methods for detection of hydrogen peroxide (H2O2) were established. These researches not only could develop the contents of study on the direct electrochemsitry of proteins, but also could extend the application range of nanomaterials and ionic liquids. The thesis consisted of three chapters and the main contents are as follows:1. The progress of the application of nanomaterials and ionic liquids in the study of protein modified electrode was reviewed with 110 references, and the contents of the thesis was also introduced.2. Two kinds of Mb modified electrodes, including Mb-GG-EMIMBF4/Pd/CILE and CS/CeO2/Mb/Au/CILE, were fabricated. The behaviors of direct electrochemistry and electrocatalysis about the two modified electrodes above were investigated and the new methods for detection of H2O2 were established. The experiments demonstrated that a pair of stable and quasi-reversible redox peaks appeared for Mb on the two kinds of modified electrodes, repectively. The electron transfer rate constants (ks) between Mb and the modified electrode were caculated to be 4.82 s-1 and 4.74 s-1, repectively. Mb immobilized in the two kinds of modified electrode also displayed a good performance to the reduction of H2O2 in a linear range of 5.0×10-6～2.7×10-4 mol·L-1 and 1.0x10-6～4.5×10-4 mol～L-1. The detection limit were 1.7×10-6 mol·L-1 and 4.0×10-7 mol·L-1 (S/N=3), repectively. The apparent Michaelis-Menten constants (KM) were found to be 8.8×10-5 mol·L-1 and 2.2×10-4 mol·L-1, repectively. Compared with the former, wider linear range and lower detection limit were obtained from the latter.3. Au@Ag core-shell nanoparticles were prepared and used to fabricate the Hb modified electrode of Hb-GG-BMIMBF4/Au@Ag/CILE. The behaviors of direct electrochemistry and electrocatalysis about Hb-GG-BMIMBF4/Au@Ag/CILE were studied and the new method for detection of H2O2 were established. The experiments demonstrated that the modified electrode revealed a pair of stable and quasi-reversible redox peaks and ks between Hb and the modified electrode was estimated to be 3.26 s-1. The modified electrode also displayed a good electrocatalytic performance to H2O2 in a linear range of 1.0×10-6～1.0×10-3 mol～L-1, with a detection limit of 4.0×10-7 mol·L-1 (S/N=3).