Dynamic Speciation Analysis of Heterogeneous Metal Complexes with Natural Ligands by Stripping Chronopotentiometry at Scanned Deposition Potential (SSCP)*

Raewyn M. Town; Herman P. van Leeuwen

doi:10.1071/CH04088

RESEARCH ARTICLE

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Dynamic Speciation Analysis of Heterogeneous Metal Complexes with Natural Ligands by Stripping Chronopotentiometry at Scanned Deposition Potential (SSCP)*

Raewyn M. Town ^A ^C and Herman P. van Leeuwen ^B

+ Author Affiliations

- Author Affiliations

^A Department of Chemistry, University of Southern Denmark, 5230 Odense M, Denmark.

^B Laboratory of Physical Chemistry and Colloid Science, Wageningen University, 6703 HB Wageningen, The Netherlands.

^C Author to whom correspondence should be addressed (e-mail: rmt@chem.sdu.dk).

Australian Journal of Chemistry 57(10) 983-992 https://doi.org/10.1071/CH04088
Submitted: 31 March 2004 Accepted: 17 June 2004 Published: 1 October 2004

Abstract

Stripping chronopotentiometry at scanned deposition potential (SSCP) allows chemical heterogeneity in metal speciation to be unambiguously identified. In the labile regime, use of the Freundlich binding isotherm allows straightforward determination of parameters to describe the apparent stability and heterogeneity of metal complexes with humic substances. The extent of heterogeneity of metal binding by several humic substances follows the order Cu(ii) >> Pb(ii) > Cd(ii). The lability of metal complexes decreases from the foot to the top of the wave, and the greater the degree of heterogeneity, the more readily lability is lost. In the kinetic current regime, the Koutecký–Koryta approximation allows an expression to be obtained for the SSCP wave that provides a good estimate of the experimental data for metal complexes with moderate degrees of heterogeneity.

^* Dedicated to T. Mark ‘Fark’ Florence.

Acknowledgements

This work was performed within the framework of the BIOSPEC project funded by the European Commission’s RTD Programme ‘Preserving the Ecosystem’ (Key Action Sustainable Management and Quality of Water), under contract EVK1-CT-2001–00086.

References

Dynamic Speciation Analysis of Heterogeneous Metal Complexes with Natural Ligands by Stripping Chronopotentiometry at Scanned Deposition Potential (SSCP)*

Abstract

Acknowledgements

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