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- Beni, Valerio, et al.
(författare)
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Voltammetric behaviour at gold electrodes immersed in the BCR sequential extraction scheme media : Application of underpotential deposition–stripping voltammetry to determination of copper in soil extracts
- 2004
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Ingår i: Analytica Chimica Acta. - : Elsevier. - 0003-2670 .- 1873-4324. ; 502:2, s. 195-206
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Tidskriftsartikel (refereegranskat)abstract
- The development of mercury-free electroanalytical systems for in-field analysis of pollutants requires a foundation on the electrochemicalbehaviour of the chosen electrode material in the target sample matrices. In this work, the behaviour of gold working electrodes in the mediaemployed in the BCR sequential extraction protocol, for the fractionation of metals in solid environmental matrices, is reported. All three ofthe BCR sequential extraction media are redox active, on the basis of acidity and oxygen content as well as the inherent reducing or oxidisingnature of some of the reagents employed: 0.11M acetic acid, 0.1M hydroxylammonium chloride (adjusted to pH 2) and 1M ammoniumacetate (adjusted to pH 2) with added trace hydrogen peroxide. The available potential ranges together with the demonstrated detection oftarget metals in these media are presented. Stripping voltammetry of copper or lead in the BCR extract media solutions reveal a multi-peakbehaviour due to the stripping of both bulk metal and underpotential metal deposits. A procedure based on underpotential deposition–strippingvoltammetry (UPD-SV) was evaluated for application to determination of copper in 0.11M acetic acid soil extracts. A preliminary screeningstep in which different deposition times are applied to the sample enables a deposition time commensurate with UPD-SV to be selected sothat no bulk deposition or stripping occurs thus simplifying the shape and features of the resulting voltammograms. Choice of the suitabledeposition time is then followed by standards addition calibration. The method was validated by the analysis of a number of BCR 0.11Macetic acid soil extracts. Good agreement was obtained been the UPD-SV method and atomic spectroscopic results.
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