AGNES: a new electroanalytical technique for measuring free metal ion concentration
AGNES (absence of gradients and Nernstian equilibrium stripping) is a stripping technique consisting of two conceptual steps: (i) application of a potential program (e.g. a step at a fixed potential) generating a known concentration gain between the outer and inner concentrations of the metal at the...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2004 |
| País: | España |
| Institución: | Universitat de Lleida (UdL) |
| Repositorio: | Repositori Obert UdL |
| OAI Identifier: | oai:repositori.udl.cat:10459.1/48902 |
| Acceso en línea: | https://doi.org/10.1016/j.jelechem.2003.11.017 http://hdl.handle.net/10459.1/48902 |
| Access Level: | acceso abierto |
| Palabra clave: | Electroquímica Anàlisi electroquímica Electrochemistry Electrochemical analysis |
| Sumario: | AGNES (absence of gradients and Nernstian equilibrium stripping) is a stripping technique consisting of two conceptual steps: (i) application of a potential program (e.g. a step at a fixed potential) generating a known concentration gain between the outer and inner concentrations of the metal at the mercury electrode surface together with null gradients of the concentration profiles (inside and outside the mercury electrode) and (ii) determination of the concentration of reduced metal inside the amalgam in a stripping step. In the present implementation, the stripping step under diffusion limited conditions leads to a measured current just proportional to the free metal ion concentration. In this paper we present the basic principles of the technique, analytical expressions for a simplified model of its voltammetric implementation and a numerical study for a more refined model together with preliminary experimental results in the Cd(II)/nitrilotriacetic acid system showing how this technique can be used as an alternative to other techniques (such as ion selective electrodes) in order to determine free metal activities or concentrations in the presence of complex mixtures avoiding complications such as electrodic adsorption or complexation kinetics. |
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