Gold Nanoelectrode Ensembles for the Simultaneous Electrochemical Detection of Ultratrace Arsenic, Mercury, and Copper

• Published in: Analytical chemistry (Washington) Vol. 80; no. 13; pp. 4836 - 4844
• Main Authors: Kumar Jena, Bikash, Retna Raj, C
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.07.2008
• Subjects: Analysis methods; Analytical chemistry; Applied sciences; Arsenic; Arsenic - analysis; Chemistry; Colloids - chemistry; Copper; Copper - analysis; Electrocatalysis; Electrochemical methods; Electrochemistry - methods; Electrodes; Exact sciences and technology; Gold - chemistry; Mercury; Mercury - analysis; Microelectrodes; Nanoparticles - chemistry; Natural water pollution; Pollution; Reproducibility of Results; Scanning electron microscopy; Spectrometric and optical methods; Substrate Specificity; Water Pollutants, Chemical - analysis; Water pollution; Water treatment and pollution; Bengal; Copper II; Performance evaluation; Scanning electron microscopy; Gold; Thiol; Electrochemical method; Diffuse reflection; Anodic stripping voltammetry; Ultratrace compound; Interference; Mercury II; Silicates; X ray diffraction; Reflection spectrometry; Sol gel process; Detection limit; Simultaneous measurement; Arsenic III; Water pollution; Square wave; Signal to noise ratio
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac071064w

Simultaneous electrochemical detection of As(III), Hg(II), and Cu(II) using a highly sensitive platform based on gold nanoelectrode ensembles (GNEEs) is described. GNEEs were grown by colloidal chemical approach on thiol-functionalized solgel derived three-dimensional silicate network preassembled on a polycrystalline gold (Au) electrode. GNEEs on the silicate network have been characterized by field emission scanning electron microscopy, X-ray diffraction, diffuse reflectance spectroscopy, and electrochemical measurements. Square wave anodic stripping voltammetry (SWASV) has been used for the detection of As(III) and Hg(II) without any interference from Cu(II) at the potentials of 0.06 and 0.53 V, respectively. The GNEE electrode is highly sensitive, and it shows linear response for As(III) and Hg(II) up to 15 ppb. The detection limit (signal-to-noise ratio = 4) of the GNEE electrode toward As(III) and Hg(II) is 0.02 ppb, which is well below the guideline value given by the World Health Organization (WHO). The potential application of the GNEE electrode for the detection of As(III) in a real sample collected from the arsenic-contaminated water in 24 North Parganas, West Bengal is demonstrated. The GNEE electrode has been successfully used for the simultaneous detection of As(III), Cu(II), and Hg(II) at sub-part-per-billion level without any interference for the first time. The nanostructured electrode shows individual voltammetric peaks for As(III), Cu(II), and Hg(II) at 0.06, 0.35, and 0.53 V, respectively. The analytical performance of the GNEE electrode is superior to the existing electrodes.