Highly Sensitive and Selective Basal Plane Pyrolytic Graphite Electrode Modified with 1,4-Naphthoquinone/MWCNT for Simultaneous Determination of Dopamine, Ascorbate and Urate

• Published in: Electroanalysis (New York, N.Y.) N.Y.), 2013-03, Vol.25 (3), p.723-731
• Main Authors: Oliveira, Ananda Xavier, Silva, Saimon Moraes, Leite, Fernando Roberto Figueiredo, Kubota, Lauro Tatsuo, Damos, Flavio Santos, de Cássia Silva Luz, Rita
• Format: Article
• Language: English
• Subjects: 1,4‐Naphthoquinone; 4-Naphthoquinone; Ascorbic acid; Basal plane; Calibration; Dopamine; Electrodes; Multiwalled carbon nanotubes; Pyrolytic graphite; Sensors; Uric acid; Urine
• ISSN: 1040-0397; 1521-4109
• DOI: 10.1002/elan.201200515

The present work describes the development of a highly selective and sensitive voltammetric sensor for dopamine (DA), ascorbic acid (AA) and uric acid (UA) using a basal plane pyrolytic graphite (BPPG) electrode modified with 1,4‐naphthoquinone (NQ) adsorbed on multiwalled carbon nanotubes (MWCNT). The modified electrode showed an excellent electrochemical activity towards the oxidations of DA, AA and UA. Three well‐defined voltammetric peaks, in a buffered solution at pH 7.5, were obtained by differential pulse voltammetry (DPV) at −0.050, 0.145 and 0.270 V vs. Ag/AgCl for AA, DA and UA, respectively. Linear calibration plots were obtained in the range of 10–70 nmol L−1 for DA, 40–280 µmol L−1 for AA and 2–14 µmol L−1 for UA, with detection limits of 3 nmol L−1, 1.9 µmol L−1 and 0.1 µmol L−1, respectively. The sensor was successfully applied in human urine samples and the results showed that the modified electrode has no interferences from urine sample.