Electrochemical Determination of L-dopa in the Presence of Ascorbic Acid by Gold Nanoparticles Functionalized 8-Hydroxyquinoline Modified Glassy Carbon Electrode

A new modified glassy carbon electrode (gce) was prepared using goldnanoparticles functionalized by 8-hq. this modified surface was characterized by cyclicvoltammetry, differential pulse voltammetry, scanning electron microscopy and ft-ramanspectroscopy. the modified electrode exhibits strong electrocatalytic activity towards theoxidation of a mixture of l-dopa and ascorbic acid (aa) with reduction of over potentials.simultaneous analysis of this mixture at the conventional bare electrode surface is notfeasible. however, two well-resolved oxidation peaks for aa and l-dopa are observed in themodified electrode and can be used for the estimation of aa and l-dopa simultaneously.simultaneous analysis of aa and l-dopa using the dpv method, shows that the oxidationcurrent is linear with l-dopa concentration in the range of 3.0–10 ?m with a detection limitof about 0.31 ?m (s/n=3). the proposed method was applied for the detection of l-dopa inreal samples.