Highly sensitive response to dopamine at a modified electrode involving a composite film with Au nanoparticles dispersed in a fluorocarbon polymer

Abstract

A new approach for the highly sensitive detection of dopamine by a novel composite film involving gold nanoparticles trapped in a negatively-charged fluorocarbon polymer (Nafion) on a glassy carbon (GC) electrode fabricated by a simple method is described. Gold nanoparticles with an average diameter of 2.3 nm ± 0.2 nm are dispersed throughout the whole Nafion film. The introduction of gold nanoparticles into the Nafion film not only gives a highly active electrode surface area but also increases the conductivity of the Nafion film and the resulting Au/Nafion/GC electrode combines the advantages of the properties of gold nanoparticles and the selective pre-concentration ability of Nafion. For positively charged dopamine, the results show a decrease in the redox peak separation and a high sensitivity. The oxidation peak current of dopamine was shown to vary linearly with dopamine concentration over a wide range from 0.4 to 50.0 μmol/L with a detection limit of 0.3 μmol/L. Negatively charged ascorbic acid shows no redox waves at concentrations up to 1.0×10−4 mol/L.