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dc.contributor.authorDomingos, Rute F.
dc.contributor.authorCarreira, Sara
dc.contributor.authorGalceran i Nogués, Josep
dc.contributor.authorSalaün, Pascal
dc.contributor.authorPinheiro, Jose Paulo
dc.description.abstractThe free metal ion concentration and the dynamic features of the metal species are recognized as key to predict metal bioavailability and toxicity to aquatic organisms. Quantification of the former is, however, still challenging. In this paper, it is shown for the first time that the concentration of free copper (Cu2+) can be quantified by applying AGNES (Absence of Gradients and Nernstian equilibrium stripping) at a solid gold electrode. It was found that: i) the amount of deposited Cu follows a Nernstian relationship with the applied deposition potential, and ii) the stripping signal is linearly related with the free metal ion concentration. The performance of AGNES at the vibrating gold microwire electrode (VGME) was assessed for two labile systems: Cu-malonic acid and Cu-iminodiacetic acid at ionic strength 0.01 M and a range of pH values from 4.0 to 6.0. The free Cu concentrations and conditional stability constants obtained by AGNES were in good agreement with stripping scanned voltammetry and thermodynamic theoretical predictions obtained by Visual MinteQ. This work highlights the suitability of gold electrodes for the quantification of free metal ion concentrations by AGNES. It also strongly suggests that other solid electrodes may be well appropriate for such task. This new application of AGNES is a first step towards a range of applications for a number of metals in speciation, toxicological and environmental studies for the direct determination of the key parameter that is the free metal ion concentration.
dc.description.sponsorshipFunding for this work was provided by (i) Fundação para a Ciência e Tecnologia (FCT, Portugal): Science 2008 IST-CQE3 “Environmental Chemistry” Assistant Researcher position to RFD and Project PTDC/AAC-AMB/110595/2009, and (ii) ANR (Agence national de recherché) - FCT project N°12-IS06-0001 - SPECIES: “Mesure in situ de la spéciation des métaux trace”, by ANR Project NormaRHIZO. JG acknowledges financial support from the Spanish Ministry of Education and Science (project CTM2013-48967).
dc.relation.isformatofVersió postprint del document publicat a:
dc.relation.ispartofAnalytica Chimica Acta, 2016, vol. 920, p. 29-36
dc.rightscc-by-nc-nd (c) Elsevier, 2016
dc.subjectGold electrode
dc.titleAGNES at vibrated gold microwire electrode for the direct quantification of free copper concentrations

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cc-by-nc-nd (c) Elsevier, 2016
Except where otherwise noted, this item's license is described as cc-by-nc-nd (c) Elsevier, 2016