Simultaneous electrochemical determination of dopamine and ascorbic acid using AuNPs@polyaniline core-shell nanocomposites modified electrode.

A simple and effective strategy was proposed for synthesis of AuNPs@polyaniline (AuNPs@PANI) core-shell nanocomposites. AuNPs@PANI nanocomposites were prepared by one-step chemical oxidative polymerization of aniline using chloroaurate acid as the oxidant and AuNPs as the seeds. The synthesized AuNPs@PANI nanocomposites were characterized with transmission electron microscope and UV-vis absorption spectra. Cyclic voltammetric experiments indicated that AuNPs@PANI nanocomposites showed excellent electroactivity in neutral and even alkaline solution. The obtained AuNPs@PANI nanocomposites-modified electrode was fabricated to simultaneously determine dopamine (DA) and ascorbic acid (AA) by differential pulse voltammetry. The separation between the two peak potentials of DA and AA oxidation is 236 mV. The catalytic peak currents were linearly with the concentrations of DA and AA in the range of 10-1700 and 20-1600 μM with correlation coefficients of 0.9997 and 0.9998, respectively. The detection limits for DA and AA were 5 and 8 μM, respectively.