Modified Carbon Paste Electrode for Kinetic Investigation and Simultaneous Determination of Ascorbic and Uric Acids |
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| Authors: | Phabyanno Rodrigues?Lima Paulo?Rogério Barbosa?de?Miranda Adriano Bof?de?Oliveira Marília Oliveira?Fonseca?Goulart Lauro Tatsuo?Kubota |
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| Institution: | 1. Department of Analytical Chemistry, Institute of Chemistry, University of Campinas – UNICAMP, 13084‐971, Campinas, SP, Brazil;2. Instituto Nacional de Ciência e Tecnologia de Bioanalítica, Instituto de Química – Unicamp, Campinas, SP 13084‐971, Brazil;3. Institute of Chemistry and Biotechnology, Federal University of Alagoas, 57072‐970, Maceió‐AL, Brazil;4. Institut für Anorganische Chemie der Universit?t Bonn, Gerhard‐Domagk‐Strasse 1,D‐53121, Bonn, Germany |
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| Abstract: | The present work explores, for the first time, the electrocatalytic oxidation of ascorbic acid (AscH2) and its determination in the presence of uric acid (UA) on the in situ activated 4‐nitrophthalonitrile modified carbon paste electrode. The kinetic constant κ for the catalytic reaction for the electrocatalytic oxidation of ascorbic acid, evaluated by cyclic voltammetry, chronoamperometry and RDE voltammetry provided values around 106 L mol?1 s?1. The sensor provided a linear response range for AscH2 and UA from 5.0 up to 120.0 μmol L?1 with detection limits of 1.6 μmol L?1and 1.3 μmol L?1, respectively. The sensor was applied for the simultaneous determination of AscH2 and UA in urine samples and the average recoveries for these samples were 99.8 (±3.1)% and 99.9 (±2.1)%, respectively . |
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| Keywords: | 4‐Nitrophthalonitrile Analytical methods Ascorbic acid Uric acid Sensors |
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