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Analysis of Denatured PCR Products Modified with 7-deazapurine Bases at Hanging Mercury Drop Electrode
Dudová, Zdenka ; Špaček, Jan ; Havran, Luděk ; Pivoňková, Hana ; Fojta, Miroslav
7-deazapunines are synthetic analogues of natural purine nucleobases which can pair with pyrimidines, retaining pairing complementarity of their parent purines. There is replaced N7 atom by CH group in 7-deazapurines so that DNA modified with them don't participate in Hoogsteen basepairing and don't form alternative structures. Here is a study of 7-deazapurines incorpotated into DNA measured at HMDE by CV and ACV. While 7-deazaadenine was reduced at the HMDE, giving rise to a similar irreversible cathodic peak as the natural adenine, 7-deazaguanine didn't yield any peak analogous to the peak G due to Guanine, in Agreement with a loss of corresponding redox in 7-deazaguanine.
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Voltammetric Determination of 5-Nitroindazole Using Hanging Mercury Drop Electrode Different Electrode and Polished Silver Solid Amalgam Electrode
Hrdlička, Vojtěch ; Navrátil, Tomáš (advisor) ; Zima, Jiří (referee)
The presented Bachelor Thesis deals with a study of electrochemical behavior of 5-nitroindazole (5-NI) with the search of optimal conditions for its determination using tech- niques of DC voltammetry (DCV) and differential pulse voltammetry (DPV) at hanging mer- cury drop electrode (HMDE) and polished silver solid amalgam electrode (p-AgSAE), and with the comparison of reached limits of quantification (LQ ). The optimal conditions found for determination of 5-NI in deionized water using DPV at HDME were as follows: Britton-Robinson (BR) buffer of pH 8.0 and inital potential of +100 mV. The calibration dependences were measured in the concentration range from 1·10-7 to 1·10-5 mol·dm-3 with the LQ of 1.8·10-7 mol·dm-3 . Moreover, the posibility of using adsorbtion stirring voltametry (AdSV) for determination of 5-NI in BR buffer of pH 8 was investigated. The method was ineffective due to rising base- line. The mechanism of electrochemical reduction and oxidation in BR buffer of pH 8 at HMDE was investigated. It was found that the reduction of 5-NI was controlled by diffusion and the following oxidation was controlled by adsorbtion. For determination of 5-NI in deionized water using DVP at p-AgSAE, optimal conditions seemed to be as follows: BR buffer of pH 8.0 and initial potential of +100 mV....
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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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