The polarographic and voltammetric determination of 2-amino-5-sulphoamoylnaphthalene-azo-(2’-chloro-4’-nitrobenzene)

1988 ◽  
Vol 53 (1) ◽  
pp. 19-33 ◽  
Author(s):  
Jiří Barek ◽  
Jana Balsiene ◽  
Antonín Berka ◽  
Ivana Hauserová ◽  
Jiří Zima
Keyword(s):  
Detection Limit ◽  
Differential Pulse Voltammetry ◽  
Differential Pulse ◽  
Linear Potential ◽  
Polarographic Reduction ◽  
Hanging Mercury Drop Electrode ◽  
Mercury Drop Electrode ◽  
Pulse Voltammetry ◽  
Layer Chromatography

The polarographic reduction of the title azo dye was studied, a mechanism was suggested and optimal conditions were determined for analytical utilization of this process. A detection limit of 3 . 10-7 mol 1-1 was obtained using fast scan differential pulse voltammetry and 0.7 . 10-7 mol 1-1 using linear potential scan voltammetry at a hanging mercury drop electrode. The detection limit can be decreased by adsorptive accumulation of the determined substance on the surface of the hanging mercury drop electrode, to 1 . 10-8 mol 1-1 for fast scan differential pulse voltammetry and 0.6 . 10-8 mol 1-1 for linear scan voltammetry. The selectivity of the determination can be improved by preliminary separation by extraction or thin-layer chromatography.

The polarographic and voltammetric determination of semitrypane blue

1989 ◽  
Vol 54 (6) ◽  
pp. 1538-1548
Author(s):  
Jiří Barek ◽  
Ashutosh Ghosh ◽  
Jiří Zima
Keyword(s):  
Differential Pulse Voltammetry ◽  
Mercury Electrode ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Polarographic Reduction ◽  
Hanging Mercury Drop Electrode ◽  
Mercury Drop Electrode ◽  
Dropping Mercury Electrode ◽  
Pulse Voltammetry

The polarographic reduction of the azodye semitrypane blue has been studied, a mechanism has been proposed and optimal conditions have been found for the determination of this substance by TAST polarography (to 2.10-6 mol l-1) and differential pulse polarography (to 1.10-7 mol l-1) at a classical dropping mercury electrode and by fast scan differential pulse voltammetry (to 1.10-8 mol l-1) and linear scan voltammetry (to 1.10-8 mol l-1) at a hanging mercury drop electrode. The detection limit was decreased to 1.10-9 mol l-1 for fast scan differential pulse voltammetry and 1.10-10 mol l-1 for linear scan voltammetry by using adsorptive accumulation of the determined substance at the hanging mercury drop electrode.

The determination of 4-substituted derivatives of N-nitroso-N-methyl aniline by fast scan differential pulse voltammetry at a hanging mercury drop electrode

1991 ◽  
Vol 56 (12) ◽  
pp. 2815-2826 ◽  
Author(s):  
Jiří Barek ◽  
Viktor Mejstřík ◽  
Ivana Švagrová ◽  
Jiří Zima
Keyword(s):  
Differential Pulse Voltammetry ◽  
Differential Pulse ◽  
Test Sample ◽  
Nitroso Compounds ◽  
Hanging Mercury Drop Electrode ◽  
Mercury Drop Electrode ◽  
Pulse Voltammetry ◽  
Layer Chromatography ◽  
Derivatives Of

Optimum conditions were found for the determination of N-nitroso-N-methyl aniline and its derivatives substituted in the 4 position by -CH3, -OCH3, -Cl, -CN, -OH or -NO2 groups by fast scan differential pulse voltammetry at a hanging mercury drop electrode in the concentration range 1 10-5-2 10-7 mol l-1. It was demonstrated that these techniques are useful for the analysis of a mixture of the test substances either directly or after separation by thin-layer chromatography and that false positive results can be eliminated by UV irradiation of the test sample. An attempt to further increase the sensitivity by adsorptive accumulation of the test substances on the surface of the hanging mercury drop electrode was not successful as the test N-nitroso compounds are practically not adsorbed on this electrode.

The polarographic and voltammetric determination of 2,6-dichloro-4-nitro-2'-acetylamino-4'-diethylaminoazobenzene

1990 ◽  
Vol 55 (2) ◽  
pp. 379-390 ◽  
Author(s):  
Jiří Barek ◽  
Dagmar Civišová ◽  
Ashutosh Ghosh ◽  
Jiří Zima
Keyword(s):  
Detection Limit ◽  
Differential Pulse Voltammetry ◽  
Mercury Electrode ◽  
Differential Pulse ◽  
Test Substance ◽  
Polarographic Reduction ◽  
Hanging Mercury Drop Electrode ◽  
Mercury Drop Electrode ◽  
Dropping Mercury Electrode ◽  
Pulse Voltammetry

The polarographic reduction of the title azo dye has been studied, a mechanism has been proposed and optimal conditions have been found for its analytical use. The detection limit using a classical dropping mercury electrode was 2 . 10-7 mol l-1 for TAST polarography and 1 . 10-8 mol l-1 for differential pulse polarography. Using a hanging mercury drop electrode, the detection limit was 9 . 10-9 mol l-1 for fast scan differential pulse voltammetry and 1 . 10-8 mol l-1 for linear scan voltammetry. Adsorption accumulation of the test substance on the surface of the hanging mercury drop electrode led to a further decrease in the detection limit to 1 . 10-9 mol l-1 for fast scan differential pulse voltammetry and 7 . 10-10 mol l-1 for linear scan voltammetry.

Polarographic and voltammetric determination of 6-mercaptopurine and 6-thioguanine

1986 ◽  
Vol 51 (11) ◽  
pp. 2466-2472 ◽  
Author(s):  
Jiří Barek ◽  
Antonín Berka ◽  
Ludmila Dempírová ◽  
Jiří Zima
Keyword(s):  
Detection Limit ◽  
Differential Pulse Voltammetry ◽  
Detection Limits ◽  
Differential Pulse ◽  
Voltammetric Determination ◽  
Differential Pulse Polarography ◽  
Hanging Mercury Drop Electrode ◽  
Pulse Polarography ◽  
Pulse Voltammetry

Conditions were found for the determination of 6-mercaptopurine (I) and 6-thioguanine (II) by TAST polarography, differential pulse polarography and fast-scan differential pulse voltammetry at a hanging mercury drop electrode. The detection limits were 10-6, 8 . 10-8, and 6 . 10-8 mol l-1, respectively. A further lowering of the detection limit to 2 . 10-8 mol l-1 was attained by preliminary accumulation of the determined substances at the surface of a hanging mercury drop.

The voltammetric determination of 4-nitrobiphenyl

1991 ◽  
Vol 56 (3) ◽  
pp. 595-601 ◽  
Author(s):  
Jiří Barek ◽  
Gulamustafa Malik ◽  
Jiří Zima
Keyword(s):  
Differential Pulse Voltammetry ◽  
Differential Pulse ◽  
Voltammetric Determination ◽  
Hanging Mercury Drop Electrode ◽  
Optimum Conditions ◽  
Mercury Drop Electrode ◽  
Working Electrode ◽  
Pulse Voltammetry ◽  
Unstirred Solution

Optimum conditions were found for the determination of 4-nitrobiphenyl by fast scan differential pulse voltammetry at a hanging mercury drop electrode in the concentration range 1 . 10-5 to 2 . 10-7 mol l-1. A further increase in sensitivity was attained by adsorptive accumulation of this substance on the surface of the working electrode, permitting determination in the concentration range (2 – 10) . 10-8 mol l-1 with one minute accumulation of the substance in unstirred solution or (2 – 10) . 10-9 mol l-1 with three-minute accumulation in stirred solution. Linear scan voltammetry can be used to determine 4-nitrobiphenyl in the concentration range (2 – 10) . 10-9 mol l-1 with five-minute accumulation in stirred solution, with the advantage of a smoother baseline and smaller interference from substances that yield only tensametric peaks.

The Polarographic and Voltammetric Determination of 1-(3'-Carbamoylphenyl)-3,3-dimethyltriazene

1992 ◽  
Vol 57 (11) ◽  
pp. 2263-2271
Author(s):  
Jiří Barek ◽  
Jana Kubíčková ◽  
Viktor Mejstřík ◽  
Jiří Zima
Keyword(s):  
Differential Pulse Voltammetry ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Test Substance ◽  
Polarographic Reduction ◽  
Hanging Mercury Drop Electrode ◽  
Optimal Conditions ◽  
Pulse Polarography ◽  
Pulse Voltammetry

A study was made of the polarographic reduction of the title triazene, a mechanism was proposed for this process and optimal conditions were found for its analytical application using tast polarography in the range 1 . 10-4 - 2 . 10-6 mol l-1, differential pulse polarography in the range 1 . 10-4 - 2 . 10-7 mol l-1 and fast scan differential pulse voltammetry at a hanging mercury drop electrode in the range 1 . 10-4 - 2 . 10-7 mol l-1. The sensitivity of the latter technique was increased through adsorptive accumulation of the test substance on the surface of the working electrode, permitting determination in the concentration range 1 . 10-7 - 2 . 10-9 mol l-1.

Polarographic and Voltammetric Determination of 1-(2'-Nitrophenyl)-3,3-dimethyltriazene

1993 ◽  
Vol 58 (9) ◽  
pp. 2021-2038 ◽  
Author(s):  
Jiří Barek ◽  
Dana Dřevínková ◽  
Jiří Zima
Keyword(s):  
Differential Pulse Voltammetry ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Hanging Mercury Drop Electrode ◽  
Optimum Conditions ◽  
Concentration Region ◽  
Mercury Drop Electrode ◽  
Pulse Polarography ◽  
Pulse Voltammetry

The polarographic behaviour of 1-(2'-nitrophenyl)-3,3-dimethyltriazene in mixed aqueous-methanolic solvent was investigated by tast polarography, differential pulse polarography, and fast scan differential pulse voltammetry at a hanging mercury drop electrode. A mechanism is suggested for the reduction of the compound investigated. The optimum conditions were found for the determination of this analyte by tast polarography over the concentration region of 100 to 2 μmol l-1 and by differential pulse polarography or fast scan differential pulse voltammetry at a hanging mercury drop electrode over the region of 100 to 0.2 μmol l-1. Additional sensitivity increase in the last-mentioned technique was achieved by adsorptive accumulation of analyte on the hanging mercury drop surface, owing to which the concentration region was depressed to 0.1 - 0.02 μmol l-1.

The polarographic and voltammetric determination of trypane blue

1988 ◽  
Vol 53 (5) ◽  
pp. 921-928
Author(s):  
Jiří Barek ◽  
Janina Balsiene ◽  
Barbara Tietzová ◽  
Jiří Zima
Keyword(s):  
Detection Limit ◽  
Mercury Electrode ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Hanging Mercury Drop Electrode ◽  
Mercury Drop Electrode ◽  
Pulse Polarography ◽  
Dropping Mercury Electrode ◽  
Pulse Voltammetry

The reduction of mutagenic bisazodye trypane blue has been studied at a mercury electrode, a mechanism has been proposed and optimal conditions found for its analytical application. The use of a dropping mercury electrode with a renewable surface yielded a detection limit of 8 . 10-7 mol l-1 for TAST polarography, and 8 . 10-8 mol l-1 for differential pulse polarography; the use of a hanging mercury drop electrode with an unrenewed surface during the measurement yielded detection limit of 6 . 10-8 mol l-1 for fast scan differential pulse voltammetry and 4 . 10-8 mol l-1 for linear scan voltammetry. Preliminary adsorptive accumulation of the determined substance on the surface of the hanging mercury drop electrode led to a decrease in the detection limit to 5 . 10-9 mol l-1 for linear scan voltammetry.

The polarographic and voltammetric determination of 1-phenyl-5-hydroxy-3-carbamoylpyrazol-4-azo-(4'-ethoxycarbonylbenzene)

1987 ◽  
Vol 52 (1) ◽  
pp. 81-87 ◽  
Author(s):  
Jiří Barek ◽  
Dagmar Civišová
Keyword(s):  
Detection Limit ◽  
Differential Pulse Voltammetry ◽  
Mercury Electrode ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Polarographic Reduction ◽  
Pulse Polarography ◽  
Dropping Mercury Electrode ◽  
Pulse Voltammetry

The polarographic reduction of the title azodye has been studied, a mechanism has been proposed for this process and conditions have been found for the determination of this substance by TAST polarography, with a detection limit of 7 . 10-7 mol l-1, differential pulse polarography at a dropping mercury electrode with a detection limit of 3.5 . 10-7 mol l-1, fast scan differential pulse voltammetry at a static mercury drop electrode with a detection limit of 6.9 . 10-9 mol l-1 and voltammetry with linearly increasing voltage at a hanging mercury drop with a detection limit of 1.6 . 10-9 mol l-1.

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