Selective electrochemical determination of dopamine at p-nitroaniline film-hole modified glassy carbon electrodes

Abstract

Herein, we report determination of dopamine (DA) at modified glassy carbon electrode (GCE) with a film produced by reduction of diazonium generated from p-nitroaniline (PNA). Pores were created purposely by stripping pre-deposited gold nanoparticles (AuNPs) in the modifier film. The modified electrodes were characterized electrochemically by common redox probes: hydroquinone (HQ), hexacyanoferrate [(Fe(CN)6)]^3- and hexamine ruthenium(III) [Ru(NH3)6]³⁺. Comparison was made for the cyclic voltammetric and amperometric response of DA using the modified electrodes against the bare GCE in phosphate buffer solution (PBS) of pH 7.5. The bare and modified GCE showed a linear response to DA in the concentration range of 0.2-2.2 mM and 5-35 µM with detection limit of 0.015 mM and 0.6112 µM, respectively. The modified electrode showed high sensitivity, well selectivity, good anti-interference ability, durable stability and good electrode reproducibility for determining DA. The reported modified electrode is a promising sensor for use in electroanalysis of DA.

KEY WORDS: Diazonium, p-Nitroaniline, Gold nanoparticles, Dopamine, Ascorbic acid, Glassy carbon electrode

Bull. Chem. Soc. Ethiop. 2017, 31(3), 361-372

DOI: http://dx.doi.org/10.4314/bcse.v31i3.1