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The Use of Electrochemical Stripping Methods for Lead and Cadmium Speciation in Soil Solutions
Šestáková, Ivana ; Jaklová Dytrtová, J. ; Jakl, M. ; Navrátil, Tomáš ; Fojta, Miroslav
Soil solution is an aqueous phase of soil which is affected by plant root systems. The soil solution contains nutrients, organic and inorganic soil substances and also exudates – substances released by plant roots (e.g. low molecular weight organic acids). For the bioaccumulation (transport from soil into plants) the free metal ions and labile complexes contents (usually in trace amounts) in soil solution are important. That is why the electrochemical methods using working electrode preconcentration step, i.e. differential pulse anodic stripping voltammetry, anodic stripping square-wave voltammetry and stripping chronopotentiometry with constant current, are applicable. Mentioned methods combined with the hanging mercury drop electrode were tested for the cadmium and lead speciation possibilities in model and also real soil solutions.
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Complexation of zinc ions by the phytochelatin PC2
Šestáková, Ivana ; Serrano, N. ; Diaz-Cruz, J. M. ; Arino, C.
Contrary to mammaliam metallothioneins, where Zn(II) is coordinated by four sulphur atoms, no structural studies are available for complexes of Zn- phytochelatins. Based on earlier experiences with electrochemical study of complexes of simplest phytochelatin-PC2- with cadmium ions, voltammetry and constant current chronopotentiometry on HMDE were used to study complexation of this phytochelatin with zinc ions. Overlapping of signals was overcome by the application of multivariate curve resolution method by alternating least squares. As result, structures with two or four sulphur atoms participating on Zn(II) complexation were suggested.
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