| Two parts are included in this thesis. In the first part of this thesis, the definiens, property, and preparation method of chemical modified electrode(CME) are mentioned. Then, the preparation method and the application progress of the carbon nanotubes modified electrode in the electroanalytical chemistry are reviewed. In the second part, we mainly focused on the the preparation of the composite films of polymers with multi-walled carbon nanotubes modified electrode, and its electroanalytical application are researched.Carbon nanotubes have attracted tremendous interest owing to their unique mechanical, optical, electrical and chemical properties, especially their electrical properties such as electrocatalytic activity and excellent resistance to surface fouling. Carbon nanotubes have been added into polymers to improve their electrical conductivity and mechanical properties. In the preparation of these materials, the effective utilization of MWCNTs depends strongly on the ability to disperse nanotubes homogeneously throughout the matrix and to achieve strong interfacial bonding between MWCNTs and the matrix in order to ensure load translation. However, the development of polymers/CNTs composites has been impeded by the inability to disperse CNTs in the polymer matrix.In this thesis, the composites of poABA with MWCNTs, which are prepared by ultrasonic action, have excellent electro-activity and solubility in the aqueous solution. The resulting composites can be directly applied to modify electrode and form the composites with molecularly imprinted polymers. Our investigating results showed that this composites not only presented the excellent performance of MWCNTs and polymers, but also displayed excellent synergistic effect in the overall performance. The works are included in the followings:1. The Preparation of the Carbon Nanotubes/Poly(o-aminobenzoic acid) Composites Modified Electrode and its Electrocatalytic Oxidation for Uric AcidThe poly(o-aminobenzoic acid) could be well formed on the surface of multi-walled carbon nanotubes (MWCNTs) under ultrasonic action. The resulting composites of poABA with MWCNTs have excellent electro-activity and solubility in the aqueous solution, and the composites could be well prepared on the surface of the graphite electrode by the electro-polymerizing method. The composite not only showed the better selectivity for uric acid (UA), but also presented the excellent sensitivity,stability and the rapid response time for UA. The result showed that under the optimum conditions, the peak current of electrochemical-oxidation UA was linear with the UA concentration in the range of 7.0×10-8 to 1.0×10-5 mol/L and a 3×10-8 mol/L detection limit for UA was obtained. The sensor has been successfully applied to the determination of UA in human urine sample.2. The Preparation of the Composite Films of Molecularly Imprinted Polymers with Carbon Nanotubes and its Electroanalytical ApplicationThis study aims to synthesize the composite films of molecularly imprinted polymers with multi-walled carbon nanotubes(MWCNTs/MIPs) modified electrode in an effort to develop electrochemistry sensor. In order to overcome the limitations of the inability to disperse CNTs in the polymer matrix, the composite material of MWCNTs with poly-(o-aminobenzoic acid) were prepared based on the ultrasonic action firstly and then used in the preparation of MWCNTs/MIPs. Our investigating results on this MWCNTs/MIPs modified electrode showed that this modified electrode not only presented the better selectivity for isoniazid, but also presented the excellent sensitivity, the better stability and the rapid response time for isoniazid due to the electro-catalytic effect and the electronic channel effect of MWCNTs in this composite molecular imprinted film. Based on these findings, a novel electrochemical sensor for isoniazid was developed and a new scheme to improve the electrochemical sensing ability in the molecular imprinted films was also developed. Under the optimum conditions, the peak current of electrochemical-oxidation isoniazid was linear with the isoniazid concentration in the range of 5.0×10-7 to 9.0×10-5 mol/L and a 8×10-8 mol/L detection limit for isoniazid was obtained. The sensor has been successfully applied to the determination of isoniazid in human urine sample. |
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