RESUMO
Multi-walled carbon nanotubes-tungsten oxide (MWCNTs-WOx) nanocomposites were fabricated on glassy carbon electrode (GCE) through a simple electrodeposition method,in which WOx were fabricated on MWCNTs. The morphology and constitution were characterized by field emission scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS). Electrochemical characterization of modified electrode was done by electrochemical impedance spectroscopy (EIS). The cyclic voltammogram (CV)method was adopted to investigate the electrochemical behavior of dopamine (DA) on MWCNTs-WOx-modified glassy carbon electrode, and a new detection method for DA was developed by differential pulse voltammetry (DPV). The results showed that MWCNTs-WOx nanocomposites had obvious electrocatalytic effect on DA in phosphate buffer solution (pH=6.5). Under the optimized experimental conditions, the DA peak current demonstrated a good linear relationship with concentration in the range of 0.05-1.00 mmol/L, and the detection limit was 17 μmol/L(S/N=3). Effects of different experimental parameters on the response current of the modified electrode were investigated,and it was found that the prepared electrochemical sensor displayed good reproducibility,high selectivity and strong anti-interference ability. UA did not interfere with the detection of DA. A new electrochemical method for the quantitative determination of DA was established and successfully applied to the determination of dopamine hydrochloride injection samples.