Selective Determination of Dopamine, Ascorbic Acid and Uric Acid at SDS-MWCNTs Modified Glassy Carbon Electrode

In this paper, dopamine(DA) and uric acid(UA) were selectively determined using cyclic voltammetry and differential pulse voltammetry in the presence of ascorbic acid(AA) by a glass carbon electrode modified with sodium dodecyl sulfate(SDS) and multi-walled carbon nanotubes(MWCNTs). The composite electrode exhibited excellent selectivity and sensitivity toward DA, UA and AA. It was found that the three anodic peaks can be well separated compared with the bare glassy carbon electrode. Using differential pulse voltammetry, AA, DA and UA were determined in phosphate buffer solutions at pH 7, results display that AA, DA and UA were obtained in the linear range of 4.0x10(-4) - 3.5x10(-3) mol/L, 8.0x10(-7) - 8.0x10(-5) mol/L and 4.0x10(-6) - 3.0x10(-5) mol/L, the detection limits were 3.0x10(-6), 1.0x10(-8) and 4.0x10(-8) mol/L for AA, DA and UA respectively.