Application of graphene to modified ionic liquid graphite composite and its enhanced electrochemical catalysis properties for levodopa oxidation

• A novel modified electrode was constructed using graphene-modifier/ionic liquid.
• The effect of graphene on electrochemical properties of modifier was investigated.
• Sensitivity, reproducibility and low detection limit, make the nanostructured modified electrode very useful for accurate determination of levodopa.

A novel kind of structurally uniform and electrocatalytic activity material formed by combination of graphene (GR), 1-(6,7-dihydroxy-2,4-dimethylbenzofuran-3-yl) ethanone (DE) and ionic liquid (IL) and used to modify carbon paste electrode (GR–DE–IL/CPE). The electrochemical properties of DE (as a modifier) in graphene paste electrode-based ionic liquids were studied in the aqueous solution. The fabricated GR–DE–IL/CPE was further used for the successful determination of levodopa (LD), and it exhibited an excellent electrocatalytic activity toward LD with a lower overvoltage, good electrochemical performances with higher conductivity and lower electron transfer resistance. It has been found that under optimum condition in CV, the oxidation of LD occurs at a potential about 400 mV less positive than that of an unmodified carbon paste electrode. Based on differential pulse voltammetry, the oxidation of LD exhibited a dynamic range between 0.015 and 1000 μM and a detection limit (3σ) of 5.0 ± 1 nM. Finally, this method was used for the determination of LD in real samples, using standard addition method.

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