Gold Nanoparticles-Thiol-Functionalized Reduced Graphene Oxide Coated Electrochemical Sensor System for Selective Detection of Mercury Ion

• Published in: Journal of the Electrochemical Society Vol. 165; no. 8; pp. B3046 - B3053
• Main Authors: Devi, N. Ramila, Sasidharan, Manickam, Sundramoorthy, Ashok K.
• Format: Journal Article
• Language: English
• Published: The Electrochemical Society 01.01.2018
• ISSN: 0013-4651; 1945-7111
• DOI: 10.1149/2.0081808jes

Reduced graphene oxide (rGO) dispersion was obtained by ultrasonication of rGO powder using dodecanethiol (-SH) as an exfoliating agent. Using thiol chemistry, the gold nanoparticles (Au-NPs) were assembled onto the rGO-SH modified glassy carbon electrode (GCE) which showed a strong binding with the surface of the coated electrode. Furthermore, the GCE/rGO-SH/Au-NPs electrode was used to detect mercury (Hg2+) ions in the aqueous solution. When employed as a working electrode, Hg2+ ions get adsorbed on the electrode surface which was later electrochemically oxidized by differential pulse voltammetry (DPV) with the enhanced oxidation current at +0.172 V. Moreover, this sensor platform showed linear response for Hg detection from 1-10 μM in phosphate buffer saline (PBS) solution and the detection limit was found to be 0.2 μM (S/N = 3). The characterization of the Au-NPs and rGO-SH films were studied by Fourier-transform infrared spectroscopy (FT-IR), UV-Visible spectroscopy, transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM). The application of the prepared sensor was also demonstrated in detecting mercury ions in tap water samples with satisfactory recovery analysis.