Facile and ultra-sensitive voltammetric electrodetection of Hg 2+ in aqueous media using electrodeposited AuPtNPs/ITO

• Published in: Analytical methods 2021-06, Vol.13 (24), p.2688-2700
• Main Authors: Bagheri Hariri, Mohiedin, Siavash Moakhar, Roozbeh, Sharifi Abdar, Payman, Zargarnezhad, Hossein, Shone, Matthew, Rahmani, Seyyed Alireza, Moradi, Nasrin, Niksefat, Vahid, Shayar Bahadori, Kasra, Dolati, Abolghasem
• Format: Article
• Language: English
• ISSN: 1759-9660; 1759-9679
• DOI: 10.1039/D1AY00361E

In this study, we have investigated the use of electrodeposited Au–Pt nanoparticles (AuPtNPs) on indium tin oxide (ITO) for the detection of Hg 2+ heavy ions in water samples. The mechanism of AuPtNP electrocrystallization on ITO glass in an aqueous solution containing 0.5 mM HAuCl 4 + 0.5 mM H 2 PtCl 6 is described for the first time. The nucleation mechanism of monometallic AuNPs on ITO was found to be progressive; however, a transition from progressive to instantaneous was observed for bimetallic AuPtNPs at elevated overpotentials. The modified ITOs were then assessed for the electrodetection of Hg 2+ in aqueous media. It was shown by differential pulse voltammetry (DPV) that the sensitivity of the constructed AuPtNPs/ITO electrode toward Hg 2+ was about 2.08 μA nM −1 . An approximate detection limit of 4.03 nM Hg 2+ was achieved, which is below the permissible level of 30.00 nM Hg 2+ in drinking water, according to the World Health Organization (WHO). Characterization of AuPt nanostructures was carried out by X-ray diffraction (XRD) patterns, scanning electron microscopy (SEM), and different electrochemical techniques (cyclic voltammetry (CV), chronoamperometry, and electrochemical impedance spectroscopy (EIS)). Our results indicate a good potential of a facile and robust electrochemical assembly for on-site detection of heavy metals in water samples.