| Preparation of nanomaterials with novel structure, morphology control for fabricating new kinds of electrochemically modified electrode in order to improve the analytical performance has already been a hot area of electroanalytical chemistry. In this thesis, three kinds of nanomaterials-based (NLC, M-Au, Zn/MWCNTs) composite films and polyaniline-hemoglobin-gold nanoparticles composites were prepared and four new types of chemically modified electrode were fabricated, after which the electrochemical behaviors of glucose oxidase (GOx) and hemeglobin (Hb) were studied in details and the new methods for determination of glucose and H2O2 were developed. These studies have some theoretical and practical signification for the exploration of new methods in the preparation of morphology control of nanomaterials, the expansion of electrochemical studies. The thesis was divided into three chapters and the main contributions as follows:1. A summary on the progress of chemically modified electrodes was presented 118 references were cited.2. Nail-like nanostructured carbon (NLC) was synthesized by hydrothermal method and glucose oxidase-NLC-chitosan/glassy carbon electrode (GOx-CHIT-NLC/GCE) was fabricated and behavior of direct electrochemical of GOx and its electrocatalytic properties was studied. The results showed that the modified electrode displayed a pair of quasi-reversible redox peaks with the formal potential (E0') of -0.458 V, and the electron transfer rate constant (ks) was estimated to be 4.4 s-1 between GOx and the modified electrode. The modified electrode also exhibited excellent electrocatalytic activity towards glucose, the calibration curve for detection of glucose was linear in the range of 2.0×10-5～1.8×10-3 mol·L-1, with a high sensitivity of 1.66×102μA·(mmol·L-1·cm2)-1 and a detection limit of 1.0×10-5 mol·L-1 (S/N=3). The apparent Michaelis-Menten constant was calculated to be 5.6×10-4 mol·L-1.3. Macroporous Au modified glassy carbon electrode (M-Au-GCE) was prepared by templating method and glucose oxidase-chitosan-macroporous-Au/GCE (GOx-CHIT-M-Au/GCE) was fabricated and behavior of direct electrochemical of GOx and its electrocatalytic properties was studied. The results showed that the modified electrode displayed a pair of quasi-reversible redox peaks with the formal potential (E0') of-0.455 V, and the electron transfer rate constant (ks) was estimated to be 0.21 s-1 between GOx and the modified electrode. The modified electrode also exhibited excellent electrocatalytic activity towards glucose, the calibration curve for detection of glucose was linear in the range of 1.0×10-5～7.7×10-3 mol·L-1, with a high sensitivity of 1.16μA·(mmol·L-1)-1 and a detection limit of 3.0×10-6 mol·L-1 (S/N=3). The apparent Michaelis-Menten constant was calculated to be 5.0×10-3 mol·L-1.4. Nano-Zn was electrodeposited from a novel ionic liquid (Ethaline) and hemoglobin-chitosan-nano-Zn-multiwall carbon nanotubes/glassy carbon electrode (Hb-CHIT/nano-Zn/MWCNTs/GCE) was fabricated and behavior of direct electrochemical of Hb and its electrocatalytic properties was studied. The results showed that the modified electrode displayed a pair of quasi-reversible redox peaks with the formal potential (E0') of-0.333 V, and the electron transfer rate constant (ks) was estimated to be 20.0 s-1 between H2O2 and the modified electrode. The modified electrode also exhibited excellent electrocatalytic activity towards H2O2, the calibration curve for detection of H2O2 was linear in the range of 3.0×10-6～3.1×10-4 mol·L-1, with a high sensitivity of 1.52×101μA·(mmol·L-1)-1 and a detection limit of 1.0×10-6 mol·L-1 (S/N=3). The apparent Michaelis-Menten constant was calculated to be 3.5×10-3 mol·L-1.The studies above indicated that prepared nanomaterials (NLC, M-Au, Zn/MWCNTs)-based composite films with good biocompatibility could accelerate the direct electron transfer of redox proteins (enzymes). It can be concluded that the present studies extended the application of nanomaterials in novel electrochemical modified electrode.5. Polyaniline-hemoglobin-gold nanoparticles (PANI-Hb-Au NPs) biocomposition film was explored through the interface reaction and PANI-Hb-Au NPs/glassy carbon electrode (PANI-Hb-Au NPs/GCE) was fabricated. Effects of applied parameters on the analytical performance of the modified electrode were also investigated. The modified electrode also exhibited excellent electrocatalytic activity towards H2O2, the calibration curve for detection of H2O2 was linear in the range of 3.0×10-5～1.5×10-2 mol·L-1, with a detection limit of 2.0×10-5 mol·L-1 (S/N=3). The apparent Michaelis-Menten constant was calculated to be 7.5×10-3 mol·L-1. Accordingly, this method presented here can be extended other system, not only as biosensor, but also as drug delivery, advanced materials, bioelectronics and biofuels.
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