Polarographic Studies on Selenite Ions in Aqueous Hypophosphorous Acid Solutions

1996 ◽  
Vol 61 (7) ◽  
pp. 992-998 ◽  
Author(s):  
Salah A. El-Shatoury
Keyword(s):  
Acid Concentration ◽  
Differential Pulse ◽  
Analytical Determination ◽  
Acid Solutions ◽  
Hypophosphorous Acid ◽  
Pulse Technique ◽  
Polarographic Behaviour

The polarographic behaviour and determination of Se(IV) in hypophosphorous acid solutions of concentrations varying from 0.05 mol l-1 to 4.0 mol l-1 at 25 ± 0.1 °C were investigated. It was shown that the reduction of 5 . 10-4 mol l-1 Se(IV) at the DME takes place in two waves independent on the acid concentration. The reduction waves correspond to the transfer of 6 electrons. A mechanism of the reduction at the DME has been suggested. A method for the analytical determination of Se(IV) species in 0.1 mol l-1 and 0.05 mol l-1 hypophosphorous acid in absence and in presence of 3 . 10-6 mol l-1 Cd(II) and Zn(II) was developed using a differential pulse technique.

Polarographic Determination of 6-β-D-Glucopyranosyloxy-7-hydroxycoumarin

1996 ◽  
Vol 61 (3) ◽  
pp. 333-341
Author(s):  
Jiří Barek ◽  
Roman Hrnčíř ◽  
Josino C. Moreira ◽  
Jiří Zima
Keyword(s):  
Natural Compound ◽  
Mercury Electrode ◽  
Direct Determination ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Whitening Agent ◽  
Polarographic Behaviour ◽  
Pulse Polarography ◽  
Dropping Mercury Electrode

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.

The application of DPASV to the determination of the low temperature solubility of lead sulphate in sulphuric acid solutions

1979 ◽  
Vol 57 (9) ◽  
pp. 974-981 ◽  
Author(s):  
Eugene M. L. Valeriote ◽  
Lloyd D. Gallop ◽  
Pedro J. Aragon
Keyword(s):  
Sulphuric Acid ◽  
Pure Water ◽  
Differential Pulse ◽  
Lead Ion ◽  
Acid Solutions ◽  
Lead Acid Battery ◽  
Emf Measurements ◽  
Lead Sulphate ◽  
Standard Enthalpy Of Solution

Measurements of the solubility of lead sulphate in 35% by weight sulphuric acid, pure water, and at two intermediate acid concentrations have been made over the temperature range 25 °C to −50 °C using differential pulse anodic stripping voltammetry.Values of the standard enthalpy of solution, derived from the data and from that of other workers, have been found to be higher than those obtained from emf measurements. The extent of lead sulphate ion pairing is analyzed at 25 °C and discussed. The slowness of equilibration of acid solutions supersaturated with lead sulphate was judged of importance in deciding the relevance of the use of thermodynamically calculated lead ion concentrations with respect to lead acid battery mechanisms.

The Polarographic and Voltammetric Determination of 1(4'-Carbamoylphenyl)-3,3-dimethyltriazene

1992 ◽  
Vol 57 (6) ◽  
pp. 1230-1236
Author(s):  
Jiří Barek ◽  
Viktor Mejstřík ◽  
Saafa Toubar ◽  
Jiří Zima
Keyword(s):  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Test Substance ◽  
Hanging Mercury Drop Electrode ◽  
Optimum Conditions ◽  
Mercury Drop Electrode ◽  
Polarographic Behaviour ◽  
Pulse Polarography ◽  
Pulse Voltammetry

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.

Polarographic Determination of 7-Diethylamino-4-methylcoumarin

1995 ◽  
Vol 60 (5) ◽  
pp. 802-812
Author(s):  
Jiří Barek ◽  
Roman Hrnčíř ◽  
Josino C. Moreira
Keyword(s):  
Mercury Electrode ◽  
Differential Pulse ◽  
Polarographic Determination ◽  
Differential Pulse Polarography ◽  
Whitening Agent ◽  
Polarographic Behaviour ◽  
Pulse Polarography ◽  
Dropping Mercury Electrode ◽  
Technical Products

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.

Voltammetric determination of trace amounts of aluminium

1989 ◽  
Vol 54 (2) ◽  
pp. 370-374 ◽  
Author(s):  
Věra Stará ◽  
Miloslav Kopanica
Keyword(s):  
Linear Dependence ◽  
Differential Pulse ◽  
Hanging Mercury Drop Electrode ◽  
Pulse Technique ◽  
Aluminium Concentration ◽  
Lead And Cadmium ◽  
Effect Of Copper ◽  
Alizarin Violet ◽  
Copper Lead

Aluminium is determined voltammetrically in the form of the aluminium complex with Acid Alizarin Violet N in an acetate buffer of pH 5.2 using a hanging mercury drop electrode and the d.c. or differential pulse technique. A linear dependence between the peak current and the aluminium concentration was obtained in the range from 2.10-8 to 5.10-6 mol l-1. The interfering effect of copper, lead and cadmium is eliminated by the auxiliary complex forming reagent-glycine.

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