Influence of triton X-100 in a micellar solution and in an emulsion on the polarographic behaviour of cobalt and determination of cobalt in paint driers and varnishes by differential-pulse polarography

The Analyst ◽  
1985 ◽  
Vol 110 (11) ◽  
pp. 1365-1368 ◽  
Author(s):  
José García-Antón ◽  
José L. Guiñón
1996 ◽  
Vol 61 (3) ◽  
pp. 333-341
Author(s):  
Jiří Barek ◽  
Roman Hrnčíř ◽  
Josino C. Moreira ◽  
Jiří Zima

The polarographic behaviour was studied for 6-β-D-glucopyranosyloxy-7-hydroxycoumarin, a natural compound serving as an optical whitening agent. The substance can be quantitated by tast polarography, differential pulse polarography using a conventional dropping mercury electrode, and differential pulse polarography using a static mercury drop electrode over the regions of 20-1 000, 2-1 000, and 0.2-1 000 μmol l-1, respectively. The methods developed for the quantitation of the compound were applied to its direct determination in a raw product.


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.


1995 ◽  
Vol 60 (5) ◽  
pp. 802-812
Author(s):  
Jiří Barek ◽  
Roman Hrnčíř ◽  
Josino C. Moreira

The polarographic behaviour of the title optical whitening agent was studied in aqueous-methanolic solutions. Conditions for its quantitation were found within the concentration regions of 10 to 100 μmol l-1 by tast polarography, 1 to 100 μmol l-1 by differential pulse polarography on the conventional dropping mercury electrode, and 0.1 to 10 μmol l-1 by differential pulse polarography on a static mercury drop electrode. The analytical procedures developed were applied to the determination of the compound in technical products.


1986 ◽  
Vol 51 (1) ◽  
pp. 34-44
Author(s):  
Václav Kočmíd ◽  
Miroslav Podolák ◽  
Jiří Čoupek ◽  
Oskar Andrýsek

The polarographic behaviour of 6,7-dimethylpterin, xanthopterin, 6-pterinaldehyde, neopterin and 6-hydroxymethylpterin was investigated. These compounds are suitably determined by employing differential pulse polarography; some results suggest the possibility of their determination by cathodic stripping voltammetry with adsorptive accumulation. For all compounds, the effect of pH on polarographic reduction was examined. Under optimal conditions, the calibration curve of all compounds under investigation was linear in the range 2 . 10-6 - 1 . 10-7 mol/l and the detection limit was below 1 . 10-7 mol/l.


1994 ◽  
Vol 59 (2) ◽  
pp. 309-321
Author(s):  
Jiří Barek ◽  
Roman Hrnčíř

The polarographic behaviour of the optical whitening agent 7-[4-methyl-5-phenyl-2-(1,2,3-triazolyl)]-3-phenylcoumarin was studied in mixed aqueous-methanolic solutions. Conditions were found for quantitating the substance by tast polarography, differential pulse polarography, differential pulse voltammetry at a hanging mercury drop electrode, and adsorption stripping voltammetry over the concentration regions of 2 - 10, 0.1 - 10, 0.02 - 1 and 0.004 - 1 μmol l-1, respectively. The methods developed were applied to a direct determination of the substance in a technological product.


1992 ◽  
Vol 57 (11) ◽  
pp. 2248-2262 ◽  
Author(s):  
Jiří Barek ◽  
Dana Dřevínková ◽  
Jiří Zima ◽  
Arnold Fogg

A study has been made of the polarographic behaviour of genotoxic 1-[4'-(phenylazo)phenyl]-3,3-dimethyltriazene in mixed water-methanol medium. A mechanism has been proposed for its polarographic reduction and optimal conditions have been found for its determination by tast polarography in the concentration range 1 . 10-4 - 2 . 10-6 mol l-1 and using differential pulse polarography in the concentration range 1 . 10-4 - 2 . 10-7 mol l-1.


1991 ◽  
Vol 56 (10) ◽  
pp. 2073-2081 ◽  
Author(s):  
Jiří Barek ◽  
Safa Toubar ◽  
Jiří Zima

A study was carried out of the polarographic behaviour of the genotoxic substance 1-(2’-carbamoylphenyl)-3,3-dimethyltriazene and optimum conditions were found for its determination by tast polarography or 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 -2 . 10-7 mol 1-1. The sensivity of the determination can be further improved through adsorptive accumulation of the test substance on the surface of the hanging mercury drop electrode; five-minute accumulation in unstirred solution permits determination in the concentration range (2-10 . 10-8 mol 1-1 and two-minute accumulation in stirred solution allows determination in the range (2-10) . 10-9 mol 1-1.


1983 ◽  
Vol 48 (10) ◽  
pp. 2903-2908 ◽  
Author(s):  
Viktor Vrabec ◽  
Oldřich Vrána ◽  
Vladimír Kleinwächter

A method is described for determining total platinum content in urine, blood plasma and tissues of patients or experimental animals receiving cis-dichlorodiamineplatinum(II). The method is based on drying and combustion of the biological material in a muffle furnace. The product of the combustion is dissolved successively in aqua regia, hydrochloric acid and ethylenediamine. The resulting platinum-ethylenediamine complex yields a catalytic current at a dropping mercury electrode allowing to determine platinum by differential pulse polarography. Platinum levels of c. 50-1 000 ng per ml of the biological fluid or per 0.5 g of a tissue can readily be analyzed with a linear calibration.


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