| Electrochemical sensor has been widely used in medicine, environment and industry due to the advantages of simple operation, low cost, rapid response and micromation. Much attention has been devoted to the development of the electrochemical sensor with high sensitivity, excellent performance and commercialization. Nanomaterial has special properties such as high surface area and surface energy. It has potential applications in electrochemistry.Graphene is a flat monolayer of carbon atoms packed into a two-dimensional lattice, with unique mechanical, thermal and electronical properties. It is excepted that graphene had extensive applications in electrochemical sensor. This thesis focus on the graphene and graphene-based composites. The main points of this thesis are as follows:1. Graphene was prepared by chemical oxidation-reduction method. The graphene modified electrode can be used to detect four bases of DNA simultaneously. The combination of graphene with carbon nanotube(CNT) andβ-cyclodextrins(CD) will prevent graphene from agglomerating. The prepared graphene/CNT/β-cyclodextrins composite was used to detect guanosine with high sensitivity. This method can be extended to other biological molecules.2. Prepare biocompatiable nanocomposite based on ssDNA and graphene, which can be dispersed in water to form black suspension. The suspension was stable after stored for a long time. Moreover, the ssDNA-graphene is a potential immobilization material because it is biocompatibility with high surface area. The direct electrochemical of GOD was researched, with electron transfer rate 4.14 s-1. The prepared glucose biosensor displayed high sensitivity, good selectivity and long-term stability.3. Prepare graphene and magnetic ferroferric oxide nanocomposite, which was water-soluble and magnetic. The G-Fe3O4/GCE showed good electrocatalytic activity in the reduction of H2O2 with detection limit 5.4μmol·L-1. It possess good anti-interference to ascorbic acid and uric acid. |
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