Electrochemical generation of hydridopentamminerhodium(III) and its reaction with molecular oxygen

1969 ◽  
Vol 47 (22) ◽  
pp. 4241-4246 ◽  
Author(s):  
Leslie E. Johnston ◽  
John A. Page
Keyword(s):  
Molecular Oxygen ◽  
Saturated Calomel Electrode ◽  
Mercury Electrode ◽  
Reduction Wave ◽  
Polarographic Reduction ◽  
Ammoniacal Solution ◽  
Electrochemical Generation ◽  
Dropping Mercury Electrode

The electrochemistry of Rh(NH3)5OH2+ has been studied in a buffered ammoniacal solution. The polarographic reduction wave at the dropping mercury electrode had E1/20 equal to −1.10 V (vs. saturated calomel electrode) in a 0.10 M NH3 – 0.10 M NH4ClO4 electrolyte, and gross Hg cathode electrolysis at −1.19 V produced a stable Rh(NH3)5H2+ hydride species. Both reductions were found to take place through a Rh(I) intermediate.The reaction of the Rh(NH3)5H2+ with molecular O2 in the ammoniacal electrolyte was also studied. The product was demonstrated to be a stable Rh(NH3)4(OH)(O2H)+ hydroperoxo species.

Polarographic and voltammetric determination of N,N’-dinitrosopiperazine

1991 ◽  
Vol 56 (7) ◽  
pp. 1434-1445 ◽  
Author(s):  
Jiří Barek ◽  
Ivana Švagrová ◽  
Jiří Zima
Keyword(s):  
Mercury Electrode ◽  
Linear Sweep Voltammetry ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Polarographic Reduction ◽  
Concentration Region ◽  
Pulse Polarography ◽  
Chemical Efficiency ◽  
Dropping Mercury Electrode

Polarographic reduction of the genotoxic N,N’-dinitrosopiperazine was studied and its mechanism was suggested. Optimum conditions were established for the determination of this substance by tast polarography over the concentration region of 1 . 10-3 to 1 . 10-6 mol l-1 and by differential pulse polarography on the conventional dropping mercury electrode or by fast scan differential pulse voltammetry and linear sweep voltammetry on a hanging mercury drop electrode over the concentration region of 1 . 10-3 to 1 . 10-7 mol l-1. Attempts at increasing further the sensitivity via adsorptive accumulation of the analyte on the surface of the hanging mercury drop failed. The methods are applicable to the testing of the chemical efficiency of destruction of the title chemical carcinogen based on its oxidation with potassium permanganate in acid solution.

The polarographic and voltammetric determination of 5-(3-phenoxysulphenylazo)-6-hydroxy-3-cyano-1,4-dimethyl-2-pyridone

1989 ◽  
Vol 54 (8) ◽  
pp. 2105-2119 ◽  
Author(s):  
Jiří Barek ◽  
Ivana Švagrová-Hauserová ◽  
Jiří Zima
Keyword(s):  
Mercury Electrode ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Determination Limit ◽  
Polarographic Reduction ◽  
Optimal Conditions ◽  
Pulse Polarography ◽  
Dropping Mercury Electrode ◽  
Layer Chromatography

The polarographic reduction of the title azodye has been studied, a mechanism was proposed and optimal conditions were found for the determination of this substance by TAST polarography in the range 5.10-5-2.10-6 mol l-1 and differential pulse polarography at a dropping mercury electrode in the range 5.10-5-2.10-8 mol l-1. The sensitivity was further increased by adsorptive accumulation of the determined substance on the surface of a hanging mercury drop electrode with linear scan voltammetry (determination limit 5.10-10 mol l-1). The selectivity was increased by prior separation of the determined azodye using thin layer chromatography and by transferring the substance adsorbed on the surface of the hanging mercury drop to a new base electrolyte solution.

Polarographic reduction of some oxazolones at the dropping mercury electrode

2007 ◽  
Vol 32 (3) ◽  
pp. 489-495
Author(s):  
Hussein M. Fahmy ◽  
Hamed A. Daboun ◽  
Mona M Hussein ◽  
Mohamed H. Elnagdi
Keyword(s):  
Mercury Electrode ◽  
Polarographic Reduction ◽  
Dropping Mercury Electrode

The polarographic and voltammetric determination of congo red

1987 ◽  
Vol 52 (4) ◽  
pp. 867-877
Author(s):  
Jiří Barek ◽  
Barbara Tietzová ◽  
Jiří Zima
Keyword(s):  
Congo Red ◽  
Mercury Electrode ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Polarographic Reduction ◽  
Optimal Conditions ◽  
Pulse Polarography ◽  
Dropping Mercury Electrode ◽  
Pulse Voltammetry

The polarographic reduction of the bisazodye congo red has been studied, a mechanism was proposed for this process and optimal conditions were found for determination of this substance by TAST polarography and differential pulse polarography at a dropping mercury electrode and using fast scan differential pulse voltammetry and voltammetry with linearly increasing voltage at a hanging mercury drop electrode. The detection limit for the latter two techniques is about 10-8 mol l-1; a further decrease in the value can be attained by prior accumulation of the determined substance by adsorption on the surface of the working electrode.

The polarographic and voltammetric determination of the 3'-halogen derivatives of N,N-dimethyl-4-aminoazobenzene

1990 ◽  
Vol 55 (12) ◽  
pp. 2904-2913 ◽  
Author(s):  
Jiří Barek ◽  
Jana Kubíčková ◽  
Viktor Mejstřík ◽  
Oldřich Petira ◽  
Jiří Zima
Keyword(s):  
Mercury Electrode ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Polarographic Reduction ◽  
Pulse Polarography ◽  
Dropping Mercury Electrode ◽  
Pulse Voltammetry ◽  
Mixed Water ◽  
Derivatives Of

The polarographic reduction of the 3'-halogen derivatives of N,N-dimethyl-4-aminoazobenzene was studied in mixed water-methanol medium and optimum conditions were found for the determination of these genotoxic substances by tast polarography in the concentration range 1 . 10-4 to 2 . 10-6 mol l-1, differential pulse polarography at a dropping mercury electrode in the range 1 . 10-4 to 2 . 10-7 mol l-1 and fast scan differential pulse voltammetry at a hanging mercury drop electrode in the range 1 . 10-6 to 2 . 10-8 mol l-1. The increase in the sensitivity resulting from adsorptive accumulation of the studied substances on the surface of a hanging mercury drop can be utilized in the determination using the latter method in the concentration range 1 . 10-8 to 2 . 10-9 mol l-1.

The Polarographic and Voltammetric Determination of N,N-Dimethyl-4-amino-3'-nitroazobenzene

1993 ◽  
Vol 58 (2) ◽  
pp. 295-309 ◽  
Author(s):  
Jiří Barek ◽  
Dana Dřevínková ◽  
Viktor Mejstřík ◽  
Jiří Zima
Keyword(s):  
Mercury Electrode ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Test Substance ◽  
Polarographic Reduction ◽  
Hanging Mercury Drop Electrode ◽  
Mercury Drop Electrode ◽  
Pulse Polarography ◽  
Dropping Mercury Electrode

The polarographic reduction of N,N-dimethyl-4-amino-3'-nitroazobenzene was studied by tast polarography and differential pulse polarography, constant potential coulometry and cyclic voltammetry and mechanism was proposed for the reduction. Optimal conditions were found for the determination of the test substance using tast polarography in concentration range 1 . 10-4 - 2 . 10-6 mol l-1, differential pulse polarography at classical dropping mercury electrode and fast scan differential pulse voltammetry at a hanging mercury drop electrode in range 1 . 10-4 - 2 . 10-7 mol l-1 and linear scan voltammetry at a hanging mercury drop electrode in range 1 . 10-5 - 2 . 10-8 mol l-1. A further increase in the sensitivity was achieved through adsorptive accumulation of the test substance on the surface of the working electrode, permitting the determination to be carried out in the concentration range 1 . 10-7 - 2 . 10-9 mol l-1.

The polarographic and voltammetric determination of N,N-dimethyl-4-amino-3'-methylazobenzene

1987 ◽  
Vol 52 (9) ◽  
pp. 2149-2159 ◽  
Author(s):  
Jiří Barek ◽  
Tibor J. Pastor ◽  
Simona Votavová ◽  
Jiří Zima
Keyword(s):  
Mercury Electrode ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Polarographic Reduction ◽  
Pulse Polarography ◽  
Practical Usefulness ◽  
Dropping Mercury Electrode ◽  
Pulse Voltammetry ◽  
Layer Chromatography

The polarographic reduction of N,N-dimethyl-4-amino-3'-methylazobenzene has been studied, a mechanism has been proposed and conditions have been found for the determination of this depolarizer using TAST polarography and differential pulse polarography at a classical dropping mercury electrode and using fast scan differential pulse voltammetry and linear scan voltammetry at a hanging mercury drop electrode. The detection limit at this electrode is about 10-8 mol l-1; a further decrease can be attained using adsorption accumulation of the determined azo-substance on the surface of the working electrode. In conclusion, the practical usefulness of these methods combined with extraction or thin-layer chromatography was verified.

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