Electrochemical behavior and voltammetric determination of the herbicide metribuzin at mercury electrodes

2001 ◽  
Vol 370 (7) ◽  
pp. 963-969 ◽  
Author(s):  
J. Skopalová ◽  
K. Lemr ◽  
M. Kotouček ◽  
L. Čáp ◽  
P. Barták
Keyword(s):  
Electrochemical Behavior ◽  
Voltammetric Determination ◽  
Mercury Electrodes

scholarly journals Electrochemical Behavior of Quinoxalin-2-one Derivatives at Mercury Electrodes and Its Analytical Use

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Milan Zimpl ◽  
Jana Skopalova ◽  
David Jirovsky ◽  
Petr Bartak ◽  
Tomas Navratil ◽  
...  
Keyword(s):  
Electrochemical Behavior ◽  
Reduction Process ◽  
Differential Pulse ◽  
Point Of View ◽  
Semiquinone Radical ◽  
Mesomeric Effect ◽  
Radical Intermediate ◽  
Mercury Electrodes ◽  
Electron Reduction

Derivatives of quinoxalin-2-one are interesting compounds with potential pharmacological activity. From this point of view, understanding of their electrochemical behavior is of great importance. In the present paper, a mechanism of electrochemical reduction of quinoxalin-2-one derivatives at mercury dropping electrode was proposed. Pyrazine ring was found to be the main electroactive center undergoing a pH-dependent two-electron reduction process. The molecule protonization of nitrogen in the position 4 precedes the electron acceptance forming a semiquinone radical intermediate which is relatively stable in acidic solutions. Its further reduction is manifested by separated current signal. A positive mesomeric effect of the nonprotonized amino group in the position 7 of the derivative III accelerates the semiquinone reduction yielding a single current wave. The suggested reaction mechanism was verified by means of direct current polarography, differential pulse, cyclic and elimination voltammetry, and coulometry with subsequent GC/MS analysis. The understanding of the mechanism was applied in developing of analytical method for the determination of the studied compounds.

Voltammetric determination of ubiquinone adsorption at mercury electrodes

1997 ◽  
Vol 9 (6) ◽  
pp. 449-453 ◽  
Author(s):  
Gunther Wittstock ◽  
Hendrik Emons
Keyword(s):  
Voltammetric Determination ◽  
Mercury Electrodes
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