Electrocatalytic detection of dopamine in the presence of ascorbic acid and uric acid using single-walled carbon nanotubes modified electrode

Schematic of preparation f-SWCNTs/GCE and detection of DA, AA and UA. [Display omitted] ► The method of fabrication f-SWCNTs/GCE is very simple and low cost. ► This method can eliminate the interference from AA and distinguish DA from UA. ► The f-SWCNTs/GCE resolved the overlap of voltammetric responses of AA, UA and DA. Single-walled carbon nanotubes (SWCNTs) fabricated by sodium dodecyl sulfate (SDS) (f-SWCNTs) modified glassy carbon electrodes (f-SWCNTs/GCE) for the simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA). The f-SWCNTs/GCE displayed very good electrochemical catalytic activities with respect to GCE. The oxidation over-potentials of DA and UA decreased dramatically, and their oxidation peak currents increased significantly at f-SWCNTs/GCE compared to those obtained at the bare GCE. Simultaneously, the oxidation peak currents of AA decreased accordingly. The f-SWCNTs/GCE not only divide the overlapping voltammetric responses of them into individual voltammetric peaks, but also totally eliminate the interference from AA and distinguish DA from UA. The catalytic peak currents obtained from square-wave voltammetry increased linearly with increasing DA concentrations in the range of 5.0×10−6 to 1.0×10−4M with a detection limit of 2.0×10−8M (S/N=3). The method was also successfully applied for determination of DA and showed good recovery in some biological fluids.