| The interest in chemically modified electrodes(CMEs) has increased tremendously during the last decade, it is one of the important of electrochemicals and electroanalytic chemicals. Now, CMEs have been founded numerous important applications in biological science, environmental science, material science and analytical science and so on. Chemically modified electrodes electrocatalytic properties promote its development, it can be applied to a variety of different processes, including the process of slow electron transfer, such as electrocatalysis of biomolecules, electrocatalytic of organic and inorganic molecules. Polymer modified electrode has the following advantages: contains a large concentration of electrical active site, easily preparation, great response signals, good stability and reproducibility, the biggeset one is very suitable for electroanalysis. Based on these advantages of the above, in this paper we were prepared several polymer film modified electrodes, and its application in electrochemical analysis were studied.1. The Poly- sulfanilic acid (ABSA) / Congo Red modified electrode and cyclic voltammetry determination of dopamineA new and simple method was proposed for preparation for poly-sulfanilic acid (ABSA) / Congo red (CR) modified glassy carbon electrode by electrochemical polymerization, and the electrochemical behavior of dopamine (DA) on the modified electrode was studied. At pH 4.0 NaAc-HAc buffer solution, the modified electrode has effective catalytic activity to the electrochemical oxidation of dopamine. The concentration of dopamine in the range of 1.0×10-72.5×10-4 mol/L have a good linear relationship between electrochemical response signals and dopamine concentration, with a detection limit of 6.9×10-8 mol/L (S/N=3), use the same method seven times for determining DA, RSD is 6.7%, shows a good reproducibility. This method can be applied to determine injection of dopamine hydrochloride sample.2. Simultaneous determination for dopamine, ascorbic acid and uric acid at the Poly- sulfanilic acid (ABSA) / Congo Red modified electrodeA simple method for fabrication of poly-sulfanilic acid (ABSA) / Congo red (CR) modified glassy carbon electrode by electrochemical polymerization, and this composite film performed effective catalysis to the electrochemical oxidation of dopamine (DA), uric acid (UA) and ascorbic acid (AA). In 0.1 mol/L NaAc-HAc buffer solution (pH 4.3), a linear relationship between anodic peak currents and AA, DA, UA concentrations was obtained. The study found the oxidation of dopamine, ascorbic acid and uric acid on the poly-sulfanilic acid (ABSA) / Congo red (CR) modified electrode were significantly increased, and different from bare glassy carbon electrode, in the mixture solution of dopamine, ascorbic acid and uric acid, their oxidation potential non-overlapping on the poly- sulfanilic acid (ABSA) / Congo red (CR) modified electrode was obtained, and the peak potentials are: ascorbic acid and dopamine oxidation peak potential separation of 300 mV, dopamine and ascorbic acid oxidation peak potential separation of 250 mV. These results shows this modified electrode can be successfully simultaneous determination for dopamine, ascorbic acid and uric acid in their mixture solution.3. The electrochemical catalysis of hydrogen peroxide on the hemoglobin- platinum-doped ordered mesoporous carbon materials modified electrodeA simple method for preparation of hemoglobin-platinum doped ordered mesoporous carbon materials modified electrode by dispensing, the electrochemical reduction of hydrogen peroxide on the modified electrode was investigated and found that the reduction of hydrogen peroxide on the modified electrode significant enhancement. It may be due to hemoglobin inherent catalase activity, platinum doped ordered mesoporous carbon material has large surface area and surface active sites, these can promote the reduction of hydrogen peroxide. In the optimal experimental conditions, a linear relationship between hydrogen peroxide electrochemical signal on the modified electrode and the concentration of hydrogen peroxide in the range of 6.5×10-41.3×10-2 mol/L, with the detection limit of 9.1×10-5 mol/L (S/N=3), shows a good reproducibility. The result indicated that the method can be used as hydrogen peroxide electrochemical sensors.
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