Full wave analysis of stripping chronopotentiometry at scanned deposition potential (SSCP): obtaining binding curves in labile heterogeneous macromolecular systems for any metal-toligand ratio.

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2020Author
Pinheiro, José-Paulo
Rotureau, Elise
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Pinheiro, José-Paulo;
Galceran i Nogués, Josep;
Rotureau, Elise;
Companys Ferran, Encarnació;
Puy Llorens, Jaume;
.
(2020)
.
Full wave analysis of stripping chronopotentiometry at scanned deposition potential (SSCP): obtaining binding curves in labile heterogeneous macromolecular systems for any metal-toligand ratio..
Journal of Electroanalytical Chemistry, 2020, p. 114436.
https://doi.org/10.1016/j.jelechem.2020.114436.
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Show full item recordAbstract
The different deposition potentials applied in Scanned Stripping ChronoPotentiometry
(SSCP) probe different values of the free metal and complex concentrations at the
electrode surface. The knowledge of these concentrations gives access to a relevant
window of the binding curve of a metal to a homogeneous or heterogeneous ligand.
Here, a suitable mathematical treatment for the determination of these surface
concentrations, when using a mercury thin film rotating disk electrode, is reported. The
proposed procedure does not require ligand excess conditions and takes advantage of
the knowledge of the free metal ion concentration in the bulk solution provided by the
technique AGNES (Absence of Gradients and Nernstian Equilibrium Stripping). It is
experimentally shown that the information derived from the SSCP points (i.e. at
different deposition potentials in a unique solution) is consistent with the speciation
results yielded by the technique AGNES in pertinent solutions prepared within a range
of metal-to-ligand ratios. Successful examples with polystyrene sulfonate, Laurentian
Fulvic acid and a peat humic acid are reported. It is concluded that, by running
consecutively SSCP and AGNES in a single solution, speciation information
corresponding to different compositions (i.e. those locally generated at the electrode surface by the end of the deposition step) can be retrieved, this enabling an easy
determination of the binding curve.
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Journal of Electroanalytical Chemistry, 2020, p. 114436European research projects
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