Electrochemical Determination of Dopamine at Pre-Anodized Helical Multi-Walled Carbon Nanotubes Modified Glassy Carbon Electrode

In this article we electrochemically investigated the determination of dopamine (DA) at pre-anodized helical multi-walled carbon nanotubes (H-MWCNTs) modified glassy carbon electrode (GCE) by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The pre-anodized H-MWCNTs/GCE could catalyze DA redox reaction greatly, and the oxidation current of DA from DPV measurement on pre-anodized H-MWCNTs/GCE was about 25 time bigger than on GCE. Furthermore, the pre-anodized H-MWCNTs/GCE could separate the oxidation peak potentials of DA, ascorbic acid (AA) and uric acid (UA) with well-defined peak separation as 164 mV for DA and UA, and 208 mV for DA and AA. The calibration curves of DA were obtained linearly in the range of 1 × 10−7 ∼ 2 × 10−6 M and 6 × 10−5 ∼ 2 × 10−4 M with the limit of detection (LOD, S/N = 3) and the limit of quantification (LOQ, S/N = 10) as 2.1 × 10−8 M and 7.0 × 10−8 M respectively. The sensor had been applied for DA measurement in dopamine injection samples with satisfactory results.