Electron transfer to aromatic hydrocarbons at the dropping mercury electrode

1959 ◽  
Vol 55 (0) ◽  
pp. 324-330 ◽  
Author(s):  
A. C. Aten ◽  
C. Büthker ◽  
G. J. Hoijtink
Keyword(s):  
Electron Transfer ◽  
Aromatic Hydrocarbons ◽  
Mercury Electrode ◽  
Dropping Mercury Electrode

The Influence of N,N'-Dialkylthioureas on the Two-Step Electroreduction of Zn(II) Ions

1998 ◽  
Vol 63 (6) ◽  
pp. 749-760 ◽  
Author(s):  
Grażyna Dalmata
Keyword(s):  
Electron Transfer ◽  
Double Layer ◽  
Rate Constant ◽  
Electrode Surface ◽  
Mercury Electrode ◽  
Impedance Method ◽  
Dropping Mercury Electrode ◽  
Wide Potential ◽  
Orientation Of Molecules

A two-step reduction of Zn(II) ions at the dropping mercury electrode in 1 M NaClO4/0.001 M HClO4 in the presence of N,N'-dialkylthioureas was examined in wide potential and frequency ranges, using the impedance method. The rate constant of the first electron transfer increases with increasing concentration of N,N'-dialkylthioureas, whereas that of the second electron transfer depends largely on the double layer effects, particularly, on the orientation of molecules on the electrode surface.

Kinetics and Mechanism of Zn(II) Ion Electroreduction in the Presence of Vetranal

2008 ◽  
Vol 73 (5) ◽  
pp. 616-626 ◽  
Author(s):  
Jolanta Nieszporek ◽  
Dorota Gugała-Fekner ◽  
Dorota Sieńko ◽  
Jadwiga Saba ◽  
Krzysztof Nieszporek
Keyword(s):  
Electron Transfer ◽  
Mercury Electrode ◽  
Surface Excess ◽  
Forward Reaction ◽  
True Rate ◽  
Half Wave ◽  
Reversible Potential ◽  
Dropping Mercury Electrode ◽  
Dc Polarography ◽  
Bridging Model

The two-step reduction of Zn(II) ions at a dropping mercury electrode in 1 M NaClO4 with addition of vetranal was examined using dc polarography, cyclic voltammetry and impedance measurements. Small changes of reversible potential of half-wave, Er1/2, values indicate that the Zn(II)-vetranal complexes formed in the solution are very unstable. A stepwise character of electron transfer in the Zn(II) ion reduction was established. The catalytic activity of vetranal is stronger in the first step of electron transfer than in the second one. The linear dependence of the true rate constant for the forward reaction, ktf, of Zn(II) electroreduction versus relative surface excess, Γ′, of vetranal at a given potential in the reaction plane, Φr, was interpreted in terms of a "bridging model".

Reduction and tensammetric pulse-polarographic currents of polynucleotides

1987 ◽  
Vol 52 (11) ◽  
pp. 2810-2818 ◽  
Author(s):  
Emil Paleček ◽  
František Jelen ◽  
Vladimír Vetterl
Keyword(s):  
Diagnostic Criteria ◽  
Pulse Width ◽  
Mercury Electrode ◽  
Pulse Amplitude ◽  
Single Strand ◽  
Pulse Polarography ◽  
Dropping Mercury Electrode ◽  
Adenylic Acid ◽  
Drop Time

The behaviour of electrochemically reducible single-strand polynucleotides (poly(adenylic acid)) and poly(cytidylic acid)) was studied by the differential (derivative) pulse polarography (DPP) and by other methods. Measurements were performed with the help of the dropping mercury electrode under various conditions specified by the pulse width, pulse amplitude, drop time etc. For the faradaic and tensammetric DPP peaks the diagnostic criteria were proposed which make it possible to classify even very small DPP peaks of double helical polynucleotides.

Determination of platinum in biological material by differential pulse polarography: Analysis in urine, plasma and tissue following sample combustion

1983 ◽  
Vol 48 (10) ◽  
pp. 2903-2908 ◽  
Author(s):  
Viktor Vrabec ◽  
Oldřich Vrána ◽  
Vladimír Kleinwächter
Keyword(s):  
Biological Material ◽  
Biological Fluid ◽  
Mercury Electrode ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Linear Calibration ◽  
Catalytic Current ◽  
Pulse Polarography ◽  
Dropping Mercury Electrode

A method is described for determining total platinum content in urine, blood plasma and tissues of patients or experimental animals receiving cis-dichlorodiamineplatinum(II). The method is based on drying and combustion of the biological material in a muffle furnace. The product of the combustion is dissolved successively in aqua regia, hydrochloric acid and ethylenediamine. The resulting platinum-ethylenediamine complex yields a catalytic current at a dropping mercury electrode allowing to determine platinum by differential pulse polarography. Platinum levels of c. 50-1 000 ng per ml of the biological fluid or per 0.5 g of a tissue can readily be analyzed with a linear calibration.

The reduction of cobalt (II) ion in thiocyanate media by pulse polarography

1983 ◽  
Vol 48 (2) ◽  
pp. 544-549 ◽  
Author(s):  
Jorge Alfredo Bolzan ◽  
Robert Tokoro
Keyword(s):  
Mercury Electrode ◽  
Thiocyanate Complex ◽  
Catalytic Wave ◽  
Pulse Polarography ◽  
Dropping Mercury Electrode ◽  
Thiocyanate Concentration

The electroreduction of cobalt(II) in aqueous thiocyanate solutions at the dropping mercury electrode depends on the thiocyanate concentration. At [SCN-] = 0.3 mol/l the intermediate cobalt(I)-thiocyanate complex does exist electrokinetically and may be responsible for the appearance of a peaked catalytic wave. The predecessor species of this intermediate may be CoSCN+ and Co(SCN)2 in similarity to the behaviour of cobalt(II) with cyanide and azide ions.

Oxidation of hydrogen peroxide at the dropping mercury electrode

1984 ◽  
Vol 49 (10) ◽  
pp. 2320-2331 ◽  
Author(s):  
Miroslav Březina ◽  
Martin Wedell
Keyword(s):  
Hydrogen Peroxide ◽  
Superoxide Anion ◽  
Ph Value ◽  
Mercury Electrode ◽  
Electrode Process ◽  
Electrochemical Processes ◽  
Dropping Mercury Electrode ◽  
Oxidation Of Hydrogen ◽  
Decreasing Ph ◽  
Rate Controlling Step

Reduction of oxygen and oxidation of hydrogen peroxide at the dropping mercury electrode are electrochemical processes strongly influenced both by the pH value and the anions in solution. With decreasing pH, both processes become irreversible, especially in the presence of anions with a negative φ2 potential of the diffusion part of the double layer. In the case of irreversible oxygen reduction, the concept that the rate-controlling step of the electrode process is the acceptance of the first electron with the formation of the superoxide anion, O2-, was substantiated. Oxidation of hydrogen peroxide becomes irreversible at a lower pH value than the reduction of oxygen. The slowest, i.e. rate-controlling step of the electrode process in borate buffers at pH 9-10 is the transfer of the second electron, i.e. oxidation of superoxide to oxygen.

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