Speciation of arsenic(III) and arsenic(V) by manganese-mediated stripping voltammetry at gold microelectrode ensemble in neutral and basic medium

Elza A. Zakharova, Galina N. Noskova, Svetlana G. Antonova, Alex S. Kabakaev

    Research output: Contribution to journalArticle

    11 Citations (Scopus)

    Abstract

    New schemes of arsenic speciation by anodic stripping voltammetry are developed at neutral pH based on the difference in electrochemical behaviour of the As(III) and As(V) forms. Detection is performed in sulphite medium (0.1 M Na2SO3) in the presence of Mn(II) (10 6 M), which is known to catalyse the reduction of As(V), making it detectable by ASV. Two speciation schemes are proposed. If As(III) > As(V), then As(III) and total As(III) + As(V) are determined in separate voltammetric cells after oxidation of As(III) to As(V) (5 min ozone purging), similar to previous studies. However, when As(V) > As(III), both As(III) and As(V) can be determined consecutively, within the same cell. In this case, two simple variants were successfully tested, depending on the size of the As(III) peak in comparison to the linearity range. The working electrode is an ensemble of gold microelectrodes obtained by HAuCl4 electrolysis at a carbon black–polyethylene composite (ratio 30:70). No purging is required, the electrode is sensitive, robust and has a long lifetime. Calculated LODs of As(III) and As(V) are 0.09 μg L 1 and 0.35 μg L 1, respectively (3σ, tdep = 20 s). The proposed procedures are fast, simple and environmental-friendly.

    Original languageEnglish
    Pages (from-to)1478-1498
    Number of pages21
    JournalInternational Journal of Environmental Analytical Chemistry
    Volume94
    DOIs
    Publication statusPublished - 8 Dec 2014

    Keywords

    • anodic stripping voltammetry
    • arsenic speciation
    • gold microelectrode ensemble
    • manganese
    • sodium sulphite

    ASJC Scopus subject areas

    • Analytical Chemistry
    • Environmental Chemistry
    • Soil Science
    • Health, Toxicology and Mutagenesis
    • Pollution
    • Waste Management and Disposal
    • Water Science and Technology
    • Public Health, Environmental and Occupational Health

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