Gold microelectrode ensembles: Cheap, reusable and stable electrodes for the determination of arsenic (V) under aerobic conditions

Research output: Contribution to journalArticle

Authors

  • Elza A. Zakharova
  • Galina N. Noskova
  • Alex S. Kabakaev
  • Neil Rees
  • Richard G. Compton

Colleges, School and Institutes

External organisations

  • University of Oxford
  • Department of Chemistry, Physical and Theoretical Chemistry Laboratory
  • Division of Chemical Technology
  • Tomsk Polytechnic University

Abstract

The determination of total arsenic through As(V) anodic stripping voltammetry (ASV) is, in some cases, preferable over As(III) ASV. The As(V) ASV procedure has no chemical reduction step from As(V) into As(III), which results in decreased analysis time and no contamination from reducting reagents. A simple and reliable procedure of As(V) determination is proposed. Anodic stripping determination of trace As(V) at gold microelectrode ensembles in diluted HCl solution in the presence of dissolved oxygen is shown. The electrode is based on a carbon black (30%)-polyethylene composite. The sensor was prepared by gold electrodeposition on the surface of the composite electrode. The given sensor is cheap, reliable and stable, especially when electrochemical activation is employed. The experimental parameters for the electrochemical determination were optimized, namely 0.005M HCl as the background electrolyte, the deposition potential -2.2V (versus Ag/AgCl in 1M KCl) and 180mVs-1 linear scan rate. Calibration curves were obtained and were linear in [As(V)] over the 1.5-45 μgL-1 range, with a LOD of 0.5 μgL-1. The effect of common interfering species is studied. The electrochemical behaviour of As(III) form is studied in the same experimental conditions. It was found that As(III) is deposited at lower potentials (starting at -0.6 V) and the sensitivity of As(III) detection is higher, but dependant on the presence of dissolved oxygen. The speciation of inorganic forms of arsenic is discussed.

Details

Original languageEnglish
Pages (from-to)1105-1115
Number of pages11
JournalInternational Journal of Environmental Analytical Chemistry
Volume93
Issue number11
Early online date18 Jun 2012
Publication statusPublished - 16 Dec 2013

Keywords

  • Aerated medium, Arsenic, As(III), As(V), Dissolved oxygen, Gold, Microelectrode, Random array of microelectrodes, Speciation, Stripping voltammetry, Total inorganic arsenic