Simultaneous determination of dopamine, ascorbic acid, and uric acid using helical carbon nanotubes modified electrode

Helical carbon nanotubes (HCNTs) as a novel carbon material have been prepared and the catalytic activities of HCNTs-modified glassy carbon electrode (GCE) towards the electrooxidation of uric acid (UA), ascorbic acid (AA), and dopamine (DA) have been investigated. Comparing with the bare GCE, the HCNTs modified GCE (HCNTs/GCE) has higher catalytic activities towards the oxidation of AA, DA, and UA. Moreover, the peak separations between AA and DA, and DA and UA at the HCNTs/GCE are 102 and 245 mV, respectively. Thus the simultaneous determination of AA, DA, and UA was carried out successfully. In the co-existence system of AA, DA, and UA, the linear response range for AA, DA, and UA are 7.5–180 μM, 2.5–105 μM and 6.7–65 μM, respectively and the detection limits (S/N = 3) are 0.92 μM, 0.8 μM and 1.5 μM, respectively.