Use of Modified Electrode of Pt/MWCNT′s/GCE in the Differential Pulse Voltammetric Determination of Levodopa

Composite of platinum coated multi-wall carbon nanotubes (Pt-MWCNT′s) was prepared by the technique of microwave assisted heating of polyhydric alcohol, and Pt-MWCNT′s modified GCE was prepared by addition of 14 μL of suspension of Pt-MWCNT′s in DMF dropwise onto surface of GCE (designated as Pt-MWCNT′s/GCE). Electrochemical behavior of levodopa at the modified electrode was studied by cyclic voltammetry in 0.05 mol·L-1 H2SO4 solution as supporting electrolyte in the potential range of 0.30-0.70 V (vs.SCE). As shown by the experimental results, a significant oxidation peak was observed at 0.548 V, and the oxidation peak current was found to be higher than that obtained at the MWCNT′s/GCE and bare GCE. Based on these findings, a selective method for determination of levodopa by differential pulse voltammetry was proposed. Linear relationship between values of oxidation peak current and concentration of levodopa was kept in the range of 8.0×10-6-2.0×10-4mol·L-1. Values of detection limit (3S/N) and average recovery found were 1.9×10-6mol·L-1 and 102.8% respectively.