High-sensitivity, selective determination of dopamine using bimetallic nanoparticles modified boron-doped diamond electrode with anodic polarization treatment

Selective detection of dopamine is still a challenge due to the strong interference from ascorbic acid (AA). A hybrid dopamine electrochemical sensor was fabricated by boron-doped diamond (BDD) film co-modified with gold nanoparticles and graphite-coated nickel nanoparticles (Au-C@Ni/BDD). Highly sensitive and selective detection toward dopamine was achieved by multiple electrochemical anodic polarization treatment (EAPT) with relatively mild voltage (+ 1.6 V vs. Ag/AgCl) on Au-C@Ni/BDD electrode. Specifically, the oxidation peak separation between ascorbic acid and dopamine reached 166 mV, and the limit of detection of dopamine was as low as 0.015 μM in a linear concentration range of 0.05–100 μM with the sensitivity up to 1.99 μA μM−1 cm−2 even in the presence of interference of high-level AA. These could be ascribed to the electrocatalytically active sites and functional oxygen-containing groups of the hybrid electrodes produced by the EAPT and the excellent catalytical activity of gold nanoparticles.