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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.
Speciation of lead in soil solution using anodic stripping voltammetry and diffusive gradient in thin film technique
Dytrtová, J. ; Šestáková, Ivana ; Jakl, M. ; Tlustoš, P.
Soil solution was obtained from pot experiments, where plant Thlaspi caerulescens Presl was grown on two different types of soil. Values for free lead ions in soil solution, determined with anodic stripping voltammetry are much smaller then values of "plant available lead", obtained from DGT technique.
Anodic stripping voltammetry application for the detection of copper in the presence of oxalic acid
Fenclová, K. ; Dytrtová, J. ; Jakl, M. ; Šestáková, Ivana ; Opekar, F.
Model solutions, prepared from cupric ions and different oxalic acid concentrations were studied with anodic stripping voltammetry. Signals of three different copper complexes were recognized.
The role of current magnitude in stripping chronopotentiommetry
Šestáková, Ivana
As a function of stripping current magnitude, regime of semi-infinite linear diffusion or complete depletion are characterized. Examples of different behaviour of system of metallothionein and cadmium ions in the dependence on value of stripping current are shown.
Determination of natural polyphenolic antioxidants on silica gel modified carbon paste electrode
Šulc, M. ; Šestáková, Ivana
Determination of flavonoids, using differential pulse voltammetry on silica gel modified carbon paste electrode reach good sensitivity and reproducibility, due to adsorptive accumulation of the analyte and renewable electrode surface. Real samples prepared from several types of vine, tea and potatoes were analyzed.
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.
Determination of Cystine, Cysteine and Homocysteine in Biological Matrix
Bašová, Pavlína ; Navrátil, Tomáš ; Šestáková, Ivana ; Novotný, Ladislav ; Šenholdová-Dlasková, Z.
In order to determine cystine, cysteine and homocysteine contents separately in a mixture of these compounds in real urine samples from patients suffering from cystinuremia and homocistinuremia, three voltammetric methods were tested: Brdička reaction, reduction of their complexes with copper ions and cathodic reduction of cystine. In all cases the hanging mercury drop electrode was used.
Voltammetric Behaviour of Cd, Zn-Metallothionein on Mercury and Carbon Composite Paste Electrodes
Šestáková, Ivana ; Navrátil, Tomáš ; Kopanica, M.
Cd(II) and Zn(II) complexes of rabbit liver metallothionein, Cd5Zn2 MT, exhibit on hanging mercury drop electrode inert behaviour, reduction takes place at adsorbed state. The behaviour corresponding to anodic stripping voltammetry on HMDE was observed at carbon composite paste electrode, using constant current chronopotentiometry.

National Repository of Grey Literature : 65 records found   beginprevious44 - 53nextend  jump to record:
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