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

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.

2004 ◽  
Vol 69 (11) ◽  
pp. 2021-2035 ◽  
Author(s):  
Kumaran Shanmugam ◽  
Jiří Barek ◽  
Jiří Zima

Polarographic and voltammetric behavior of 1,5-dinitronaphthalene was investigated using tast polarography and differential pulse polarography at a classic dropping mercury electrode and differential pulse voltammetry and adsorptive stripping voltammetry at a hanging mercury drop electrode. Optimum conditions have been found for the determination of tested substance in the concentration range 2-10 μmol l-1 in tast polarography, 0.2-1 μmol l-1 in differential pulse polarography at a classic dropping mercury electrode or differential pulse voltammetry at a hanging mercury drop electrode, and 0.02-0.1 μmol l-1 using adsorptive stripping voltammetry. A possible mechanism of the electrochemical reduction of 1,5-dinitronaphthalene at mercury electrodes is discussed.


1993 ◽  
Vol 58 (2) ◽  
pp. 295-309 ◽  
Author(s):  
Jiří Barek ◽  
Dana Dřevínková ◽  
Viktor Mejstřík ◽  
Jiří Zima

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.


1989 ◽  
Vol 54 (6) ◽  
pp. 1538-1548
Author(s):  
Jiří Barek ◽  
Ashutosh Ghosh ◽  
Jiří Zima

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.


1987 ◽  
Vol 52 (1) ◽  
pp. 81-87 ◽  
Author(s):  
Jiří Barek ◽  
Dagmar Civišová

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.


1986 ◽  
Vol 51 (11) ◽  
pp. 2466-2472 ◽  
Author(s):  
Jiří Barek ◽  
Antonín Berka ◽  
Ludmila Dempírová ◽  
Jiří Zima

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.


1997 ◽  
Vol 62 (4) ◽  
pp. 597-608 ◽  
Author(s):  
Jiří Barek ◽  
Pham Tuan Hai ◽  
Viktor Mejstřík ◽  
Josino C. Moreira ◽  
Jiří Zima

The polarographic behaviour of N,N-dimethyl-4-amino-4'-sulfoazobenzene was investigated by tast polarography and differential pulse polarography at a dropping mercury electrode, constant-potential coulometry at a large area mercury electrode and cyclic voltammetry at a hanging mercury drop electrode. Optimum conditions have been found for its determination by tast polarography in the concentration range of 2-100 μmol l-1, differential pulse polarography at a dropping mercury electrode in the concentration range of 0.2-100 μmol l-1 and by differential pulse voltammetry at a hanging mercury drop electrode in the concentration range of 0.02-10 μmol l-1. The sensitivity of the determination can be further improved by adsorptive accumulation of the test substance on the hanging mercury drop electrode. Three-minute accumulation in stirred solution allows determination in the range of 0.2-100 nmol l-1.


1992 ◽  
Vol 57 (6) ◽  
pp. 1230-1236
Author(s):  
Jiří Barek ◽  
Viktor Mejstřík ◽  
Saafa Toubar ◽  
Jiří Zima

A study was made of the polarographic behaviour of 1-(4'-carbamoylphenyl)-3,3-dimethyltriazene and optimum conditions were found for its determination by tast polarography and differential pulse polarography at a static mercury drop electrode and by fast scan differential pulse voltammetry at a hanging mercury drop electrode in the concentration range 1 . 10-4 to 2 . 10-7 mol l-1. A further increase in the sensitivity can be achieved through adsorptive accumulation of the test substance on the surface of a hanging mercury drop, permitting the determination to be extended to the concentration range 1 . 10-7 - 2 . 10-9 mol l-1.


2000 ◽  
Vol 65 (12) ◽  
pp. 1888-1896 ◽  
Author(s):  
Jiří Barek ◽  
Jiří Zima ◽  
Josino C. Moreira ◽  
Alexandr Muck

The polarographic behaviour of 1-nitropyrene was investigated by tast polarography, differential pulse polarography (both with a dropping mercury electrode), differential pulse voltammetry, and adsorptive stripping voltammetry (both with a hanging mercury drop electrode). Optimum conditions have been found for its determination by the given methods in the concentration ranges 2-100, 0.2-100, 0.1-10, and 0.001-0.01 μmol l-1, respectively.


1987 ◽  
Vol 52 (4) ◽  
pp. 867-877
Author(s):  
Jiří Barek ◽  
Barbara Tietzová ◽  
Jiří Zima

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.


1990 ◽  
Vol 55 (12) ◽  
pp. 2904-2913 ◽  
Author(s):  
Jiří Barek ◽  
Jana Kubíčková ◽  
Viktor Mejstřík ◽  
Oldřich Petira ◽  
Jiří Zima

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.


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