Simultaneous Determination of Dopamine and Ascorbic Acid Using the Nano-Gold Self-Assembled Glassy Carbon Electrode

Electrochemical behavior of dopamine (DA) was investigated at the gold nanoparticles self-assembled glassy carbon electrode (GNP/LC/GCE). which was fabricated by self-assembling gold nanoparticles on the surface Of L-cysteine (LC) modified glassy carbon electrode (GCE) via successive cyclic voltammetry (CV). A pair of well-defined redox peaks of DA on the GNP/LC/GCE was obtained at E-pa = 0.197 V and E-pc = 0.146 V. respectively. And the peak separation between DA and AA is about 0.2 V, which is enough for simultaneous determination of DA and AA. The peak currents of DA and AA were proportional with their concentrations in the range of 6.0 x 10(-8) -8.5 x 10(-5) mol L-1 and 1.0 x 10(-6) -2.5 x 10(-3) mol L-1, with the detection limit of 2.0 x 10(-8) mol L-1 and 3.0 x 10(-7) mol L-1 (S/N = 3) respectively. The modified electrode exhibits an excellent reproducibility, sensibility and stability for simultaneous determination of DA and AA in human serum with satisfactory result.