Enhanced electrochemical response in oxidative differential pulse voltammetry of dopamine in the presence of ascorbic acid at carboxyl-terminated boron-doped diamond electrodes

Takeshi Kondo, Yu Niwano, Akira Tamura, Junichi Imai, Kensuke Honda, Yasuaki Einaga, Donald A. Tryk, Akira Fujishima, Takeshi Kawai

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The differential pulse voltammetric (DPV) peak for dopamine (DA) oxidation was found to be highly amplified by the addition of ascorbic acid (AA) when carboxyl-terminated boron-doped diamond (BDD) electrodes were used as the working electrode. The DP voltammogram for a solution containing DA and AA obtained using a 4-pentenoic acid-modified BDD (4PA-BDD) electrode showed well-separated oxidation peaks for DA and AA at 0.4 and 0.6 V vs. Ag/AgCl, respectively. In addition, as the DA concentration increased at constant AA concentration, a simultaneous increase in the DA peak current density and decrease in the AA peak current density were observed. The slope of the calibration curve for the [DA] range of 1-10 μM in the presence of AA (500 μM) was seven times larger than that obtained in the absence of AA. Such an enhancement was found to be more efficient at 4PA-BDD than at oxidized-BDD, partly due to simple electrostatic effects and partly due to suppression of the polymerization of DA oxidation products by the terminal carboxyl groups. The enhanced detection method using a carboxyl-terminated BDD electrode should be an effective analytical tool, especially for determining low concentrations of DA in the presence of high concentrations of AA.

Original languageEnglish
Pages (from-to)2312-2319
Number of pages8
JournalElectrochimica Acta
Issue number8
Publication statusPublished - 2009 Mar 1



  • Boron-doped diamond
  • Carboxyl-terminated surface
  • Differential pulse voltammetry
  • Dopamine
  • Electrochemical amplification

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Electrochemistry

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