Voltammmetric Determination of Uric Acid in the Presence of Ascorbates Using Overoxidized Polypyrrol

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Voltammmetric Determination of Uric Acid in the Presence of Ascorbates Using OveroxidizedPolypyrrole Film Coated Glassy Carbon Electrodes

The voltammetric behaviour of uric acid at overoxidized polypyrrole (OPPY ) film-coated glassy carbon (GC ) electrodes was investigaied. The chemically modi- fied electrodes exhilbited an excellent permselectivity for uric acid of undissociated form in an acidic medium. The current response sensitivity of uric acid at the modi- fied electrodes was markedly increased by properly anodizing activation of underly- ing electrodes and overoxidizing treatment of polypyrrole film. The voltammetric response of uric acid at the chemically modified electrode was linearly related to itinvestigatedtion in the range of 4. 0 ×10^-7-8. 0 ×10^-5 mol/L in pH 5 buffer solu- tions. Ascorbic acid in less than 150-fold excess did not interfere with the voltam- metric determination of uric acid. The proposed procedure was utilized to determine uric acicl in human urine and serum samples without any pretreatment.