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Modified Carbon Paste Electrode for Kinetic Investigation and Simultaneous Determination of Ascorbic and Uric Acids
Author(s) -
Rodrigues Lima Phabyanno,
Barbosa de Miranda Paulo Rogério,
Bof de Oliveira Adriano,
Oliveira Fonseca Goulart Marília,
Tatsuo Kubota Lauro
Publication year - 2009
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200904694
Subject(s) - ascorbic acid , chronoamperometry , chemistry , cyclic voltammetry , carbon paste electrode , uric acid , detection limit , inorganic chemistry , nuclear chemistry , catalysis , electrode , electrochemistry , voltammetry , chromatography , organic chemistry , biochemistry , food science
The present work explores, for the first time, the electrocatalytic oxidation of ascorbic acid (AscH 2 ) 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 10 6 L mol −1 s −1 . The sensor provided a linear response range for AscH 2 and UA from 5.0 up to 120.0 μmol L −1 with detection limits of 1.6 μmol L −1 and 1.3 μmol L −1 , respectively. The sensor was applied for the simultaneous determination of AscH 2 and UA in urine samples and the average recoveries for these samples were 99.8 (±3.1)% and 99.9 (±2.1)%, respectively .