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Polyaniline (PAn) cheap raw materials, and easy to get simple synthesis, high conductivity, good stability, has been a hot research field of conductive polymers. Unique doping behavior and good electrochemical reversibility, in the electric field of analytical chemistry has conducted a lot of research. Dopamine (DA), uric acid (UA), ascorbic acid (AA) are present in the life vivo small molecules to analyze the content of these three substances of the body is of great significance, the three-component mixing system with electrochemical detection has been One of the hot spots of the research. This article was prepared by cyclic voltammetry polyaniline modified graphite electrode successfully electrochemical distinguish DA, UA, AA, three-component electro-catalytic oxidation peak current three-component detection. This paper mainly carried out the work of the following two aspects: 1. Polyaniline modified graphite (PAn / SG) electrode prepared by electrochemical deposition method, several influencing factors analysis cycle polymerization of aniline on the electrode surface, the experimental results show that the most Jia the polymerization conditions: the cyclic scanning of the upper limit is 0.90 V, a lower limit of -0.2 V, the aniline concentration of 0.020 mol / L, the scanning number of weeks to 20 weeks, the scanning speed was 0.05 V / s. By changing the different experimental parameters made the PAn film of different morphologies and by cyclic voltammetry, UV spectra, scanning electron microscopy PAn film obtained were characterized by a simple discussion of the reaction mechanism. The modified electrode is stable in air. 2 using the modified electrode, for simultaneous determination of dopamine, uric acid, ascorbic acid, a mixed solution prepared PAn / SG. In 0.5 mol / L H2SO4 solution, the oxidation peak of three very good separation between dopamine and uric acid peak potential difference of 110 mV peak potential difference of 250 mV between dopamine and ascorbic acid. Oxidation peak current of the three was a good linear relationship to its concentration in a certain concentration range, the determination of Renyi Cheng points in the three-component system, good reproducibility, detection limits are as follows: DA 1.00 × 10 -5 mol / L, and UA is 1.10 × 10 -5 mol / L, AA is 2.00 × 10 -5 Mol / L. Studied using cyclic voltammetry reversibility of the three ingredients, adsorption, and the transfer of the number of electrons and the number of protons involved in the reaction, suggesting that the reaction mechanism of the respective electrodes.
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