Chemical destruction of 4-nitrobiphenyl in laboratory waste and its monitoring by differential pulse polarography and voltammetry and by high-performance liquid chromatography

1986 ◽  
Vol 51 (8) ◽  
pp. 1604-1608 ◽  
Author(s):  
Jiří Barek ◽  
Antonín Berka ◽  
Marion Müller ◽  
Miroslav Procházka ◽  
Jiří Zima

A method for destruction of the carcinogenic 4-nitrobiphenyl in laboratory waste was elaborated based on its reduction with powdered zinc and oxidation of the produced 4-aminobiphenyl with potassium permanganate. The efficiency of the method can be checked by high-performance liquid chromatography, differential pulse polarography, and differential pulse voltammetry.

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.


1992 ◽  
Vol 57 (11) ◽  
pp. 2263-2271
Author(s):  
Jiří Barek ◽  
Jana Kubíčková ◽  
Viktor Mejstřík ◽  
Jiří Zima

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.


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.


1990 ◽  
Vol 55 (11) ◽  
pp. 2636-2647 ◽  
Author(s):  
Jiří Barek ◽  
Helena Kvapilová ◽  
Viktor Mejstřík ◽  
Oldřich Petira ◽  
Jiří Zima

The polarographic reduction of genotoxic 4-aminoazobenzene was studied, a mechanism was proposed and conditions were found for the analytical determination using Tast polarography in the range 1 . 10-4 - 2 . 10-6 mol l-1 and differential pulse polarography in the range 1 . 10-4 - 2 . 10-7 mol l-1. The sensitivity can be further increased by using fast scan differential pulse voltammetry at a hanging mercury drop electrode combined with adsorptive accumulation of the test substance on the surface of the working electrode, permitting the determination to be carried out in the range 1 . 10-7 - 2 . 10-10 mol l-1. The anodic oxidation of 4-aminoazobenzene was also studied at a glassy carbon solid electrode and conditions were found for its analytical utilization in the range 1 . 10-4 - 2 . 10-6 mol l-1 using classical or differential pulse voltammetry at a rotating disk electrode.


1993 ◽  
Vol 58 (9) ◽  
pp. 2021-2038 ◽  
Author(s):  
Jiří Barek ◽  
Dana Dřevínková ◽  
Jiří Zima

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.


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.


1990 ◽  
Vol 55 (6) ◽  
pp. 1508-1517 ◽  
Author(s):  
Jiří Barek ◽  
Dagmar Civišová ◽  
Ashutosh Ghosh ◽  
Jiří Zima

The polarographic reduction of the title azo dye was studied and optimal conditions were found for its analytical utilization in the concentration range 1 . 10-6 - 1 . 10-7 mol l-1 using differential pulse polarography and 1 . 10-6 - 1 . 10-8 mol l-1 using fast scan differential pulse voltammetry or linear scan voltammetry at a hanging mercury drop electrode. When the latter technique is combined with adsorptive accumulation of the studied substance on the surface of the hanging mercury drop, the determination limit can be further decreased to 3 . 10-9 mol l-1.


1986 ◽  
Vol 51 (10) ◽  
pp. 2083-2090 ◽  
Author(s):  
Jiří Barek ◽  
Roman Hrnčíř

Conditions were found for the determination of chemical carcinogen N,N-dimethyl-4-aminoazobenzene by TAST and differential pulse polarography, fast scan differential pulse voltammetry and linear sweep voltammetry at a hanging mercury drop electrode in a mixed aqueous-methanolic medium. The detection limit of the last two methods, approximately 10-8 mol l-1, can be further lowered by preliminary accumulation of the substance to be determined by adsorption at a working electrode. The applicability of these methods to the analysis of biological materials, directly or combined with an extraction, was demonstrated.


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.


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