Electrochemical acidity functions

2009 ◽  
Vol 74 (11-12) ◽  
pp. 1635-1646 ◽  
Author(s):  
Jiří Janata ◽  
Petr Zuman
Keyword(s):  
Mercury Electrode ◽  
Standard Potential ◽  
Liquid Junction ◽  
Experimental Realization ◽  
Dropping Mercury Electrode ◽  
Potentiometric Measurements ◽  
Reference Potential ◽  
Acidity Functions ◽  
Aqueous Standard

Experimental realization of a reference potential for potentiometric measurements in non-ideal media is discussed. A liquid junction-free reference potential is realized at a dropping mercury electrode, using the standard potential of the metallocene redox couple. This approach is particularly suitable for determination of acidity functions that are seamlessly anchored to aqueous standard buffers.

Determination of platinum in biological material by differential pulse polarography: Analysis in urine, plasma and tissue following sample combustion

1983 ◽  
Vol 48 (10) ◽  
pp. 2903-2908 ◽  
Author(s):  
Viktor Vrabec ◽  
Oldřich Vrána ◽  
Vladimír Kleinwächter
Keyword(s):  
Biological Material ◽  
Biological Fluid ◽  
Mercury Electrode ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Linear Calibration ◽  
Catalytic Current ◽  
Pulse Polarography ◽  
Dropping Mercury Electrode

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.

Polarographic and voltammetric determination of N,N’-dinitrosopiperazine

1991 ◽  
Vol 56 (7) ◽  
pp. 1434-1445 ◽  
Author(s):  
Jiří Barek ◽  
Ivana Švagrová ◽  
Jiří Zima
Keyword(s):  
Mercury Electrode ◽  
Linear Sweep Voltammetry ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Polarographic Reduction ◽  
Concentration Region ◽  
Pulse Polarography ◽  
Chemical Efficiency ◽  
Dropping Mercury Electrode

Polarographic reduction of the genotoxic N,N’-dinitrosopiperazine was studied and its mechanism was suggested. Optimum conditions were established for the determination of this substance by tast polarography over the concentration region of 1 . 10-3 to 1 . 10-6 mol l-1 and by differential pulse polarography on the conventional dropping mercury electrode or by fast scan differential pulse voltammetry and linear sweep voltammetry on a hanging mercury drop electrode over the concentration region of 1 . 10-3 to 1 . 10-7 mol l-1. Attempts at increasing further the sensitivity via adsorptive accumulation of the analyte on the surface of the hanging mercury drop failed. The methods are applicable to the testing of the chemical efficiency of destruction of the title chemical carcinogen based on its oxidation with potassium permanganate in acid solution.

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.

Polarographic and Voltammetric Determination of Trace Amounts of 3-Nitrofluoranthene

2006 ◽  
Vol 71 (11-12) ◽  
pp. 1571-1587 ◽  
Author(s):  
Karel Čížek ◽  
Jiří Barek ◽  
Jiří Zima
Keyword(s):  
River Water ◽  
Solid Phase ◽  
Mercury Electrode ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Pulse Polarography ◽  
Dropping Mercury Electrode ◽  
Separation And Preconcentration

The polarographic behavior of 3-nitrofluoranthene was investigated by DC tast polarography (DCTP) and differential pulse polarography (DPP), both at a dropping mercury electrode, differential pulse voltammetry (DPV) and adsorptive stripping voltammetry (AdSV), both at a hanging mercury drop electrode. Optimum conditions have been found for its determination by the given methods in the concentration ranges of 1 × 10-6-1 × 10-4 mol l-1 (DCTP), 1 × 10-7-1 × 10-4 mol l-1 (DPP), 1 × 10-8-1 × 10-6 mol l-1 (DPV) and 1 × 10-9-1 × 10-7 mol l-1 (AdSV), respectively. Practical applicability of these techniques was demonstrated on the determination of 3-nitrofluoranthene in drinking and river water after its preliminary separation and preconcentration using liquid-liquid and solid phase extraction with the limits of determination 4 × 10-10 mol l-1 (drinking water) and 2 × 10-9 mol l-1 (river water).

A NOTE ON THE POLAROGRAPHIC ANALYSIS OF HYDROGEN PEROXIDE

1948 ◽  
Vol 26b (12) ◽  
pp. 767-772
Author(s):  
Paul A. Giguère ◽  
J. B. Jaillet
Keyword(s):  
Hydrogen Peroxide ◽  
Mercury Electrode ◽  
Limiting Current ◽  
Diffusion Current ◽  
Polarographic Analysis ◽  
Dropping Mercury Electrode ◽  
Strychnine Sulphate

The determination of hydrogen peroxide at concentrations higher than those normally covered in polarography was studied with various electrodes. The diffusion current was found to increase linearly with the peroxide concentration up to 0.15% with the dropping mercury electrode and up to nearly 1% with a fixed platinum microelectrode. Under these conditions the limiting current was about 10 times greater than that usually observed. Although the solutions were supersaturated with oxygen, traces of strychnine sulphate were sufficient to suppress all maxima.

Polarographic determination of oxygen content and capacity in a single blood sample

1965 ◽  
Vol 20 (4) ◽  
pp. 774-778 ◽  
Author(s):  
Domenic A. Maio ◽  
James R. Neville
Keyword(s):  
Blood Sample ◽  
Oxygen Content ◽  
Rapid Determination ◽  
Mercury Electrode ◽  
Potassium Ferricyanide ◽  
Separate Determination ◽  
Polarographic Method ◽  
Dropping Mercury Electrode ◽  
Single Blood Sample

A polarographic method was described in an earlier report which permits the accurate, rapid determination of oxygen content in small samples of blood. As with the Van Slyke technic, total oxygen capacity was formerly estimated by a separate determination of the oxygen content after complete saturation with oxygen of another portion of the blood sample. Further experience with the polarographic method has revealed the feasibility of estimating both content and capacity in a single blood sample. The capacity estimate is made possible by the polarographic observation of the quantity of potassium ferricyanide required to convert ferrohemoglobin to ferrihemoglobin. The measurement of oxygen content is performed, as previously described, by the polarographically determined increase in physically dissolved oxygen caused by the release of bound oxygen. By this means, one avoids sampling and random errors inherent in the use of two separate determinations. The method requires only a brief time for performance and ordinary technical proficiency. It is also simple in application. polarographic dropping mercury electrode; oxygen tension; digitonin; potassium ferricyanide; ferrohemoglobin; ferrihemoglobin Submitted on June 24, 1964

Polarographic and voltammetric determination of genotoxic nitro derivatives of quinoline using mercury electrodes

2011 ◽  
Vol 76 (12) ◽  
pp. 1991-2004 ◽  
Author(s):  
Vlastimil Vyskočil ◽  
Ivan Jiránek ◽  
Aleš Daňhel ◽  
Jiří Zima ◽  
Jiří Barek ◽  
...  
Keyword(s):  
Differential Pulse Voltammetry ◽  
River Water ◽  
Mercury Electrode ◽  
Differential Pulse ◽  
Dropping Mercury Electrode ◽  
Separation And Preconcentration ◽  
Nitro Derivatives ◽  
Pulse Voltammetry ◽  
Derivatives Of

Electrochemical behavior of genotoxic nitro derivatives of quinoline, namely 5-nitroquinoline (5-NQ), 6-nitroquinoline (6-NQ) and 8-nitroquinoline (8-NQ), was investigated by DC tast polarography (DCTP) and differential pulse polarography (DPP), both at a classical dropping mercury electrode (DME), and by differential pulse voltammetry (DPV) and adsorptive stripping differential pulse voltammetry (AdSDPV), both at a miniaturized hanging mercury drop minielectrode (HMDmE), in buffered aqueous (for 5-NQ) or aqueous-methanolic (for 6-NQ and 8-NQ) solutions. Optimum conditions were found for the determination of 5-NQ, 6-NQ and 8-NQ by DCTP at DME (with limits of quantification, LQ ≈ 9 × 10–7, 3 × 10–7 and 2 × 10–6 mol l–1, respectively), by DPP at DME (LQ ≈ 1 × 10–8, 9 × 10–8 and 1 × 10–7 mol l–1, respectively), by DPV at HMDmE (LQ ≈ 2 × 10–8, 1 × 10–7 and 1 × 10–7 mol l–1, respectively), and by AdSDPV at HMDmE (LQ ≈ 1 × 10–8 mol l–1 for 8-NQ; an attempt at increasing the sensitivity using AdSDPV at HMDmE was not successful for 5-NQ and 6-NQ). Practical applicability of the developed methods was verified on the direct determination of the studied compounds in model samples of drinking and river water in submicromolar concentrations and on the determination in model samples of drinking and river water using preliminary separation and preconcentration by solid phase extraction (SPE) in nanomolar concentrations.

Etude polarographique de l'antimoine(III) et (V) dans le fluorure d'hydrogène anhydre et dans ses mélanges avec l'eau

1978 ◽  
Vol 56 (5) ◽  
pp. 703-708 ◽  
Author(s):  
Jacques Devynck ◽  
Bernard Tremillon ◽  
Hugues Menard ◽  
Germain Comarmond
Keyword(s):  
Electrochemical Reaction ◽  
Electrochemical Behaviour ◽  
Mercury Electrode ◽  
Analytical Applications ◽  
Dropping Mercury Electrode

The electrochemical behaviour of Sb(III) and Sb(V) in water–HF mixtures (2.5 to 50% HF) and in anhydrous HF is described. A Teflon capillary dropping mercury electrode is proposed for polarographie investigations in these fluorinated media. It is shown, by classical or puise polarography, that Sb(III) can be reduced to Sb(0), as in acidic non-fluorinated media. The electrochemical reaction becomes reversible by addition of Cl−, Br− or I−. Sb(V) is not electroactive in the various HF-media, except when it is introduced as the SbCl5. In this case, the two polarographie waves of Sb(V) disappear with time because of SbF6− formation. Analytical applications to the determination of Sb(III) in water–HF and in anhydrous HF are discussed.

Polarographic determination of selenium in tea leaves using a dropping mercury electrode

1996 ◽  
Vol 56 (2) ◽  
pp. 177-180 ◽  
Author(s):  
Guanghan Lu ◽  
Jianhua Liu ◽  
Yiping Hang ◽  
Fang Wang
Keyword(s):  
Mercury Electrode ◽  
Polarographic Determination ◽  
Tea Leaves ◽  
Dropping Mercury Electrode

Analysis of the Electrode Kinetics of Ni(II) Reduction in Thiocyanate Media on the Dropping Mercury Electrode

2000 ◽  
Vol 65 (3) ◽  
pp. 326-342
Author(s):  
María S. Crespo-Pinilla ◽  
Fernando Mata-Pérez ◽  
Rosa M. Villamañán
Keyword(s):  
Ionic Strength ◽  
Compensation Effect ◽  
Supporting Electrolyte ◽  
Mercury Electrode ◽  
Electrode Kinetics ◽  
Surface Process ◽  
Experimental Conditions ◽  
Dropping Mercury Electrode ◽  
Kinetics Of

A study of two prewaves of the Ni(II)-SCN- system was carried out under the experimental conditions when the influence of electroreduction of SCN- is negligible. Kinetics of Ni(II) reduction in thiocyanate media on the dropping mercury electrode was studied by DC Tast Polarography (DCTP) via determination of Koutecký's parameter χ; the influence of different variables was analyzed. The study of prewaves was performed using various polarographic techniques. Values of χ depend on the SCN- concentration, pH, ionic strength (Ψ-effect) and on the nature of the supporting electrolyte. The number of electrons n, the transfer coefficient α, the stoichiometric number ν, ∆H≠, and ∆S≠ were determined (compensation effect). The first prewave has character of a reaction in the solution, the second prewave is a surface process. Main features of both mechanisms are common: catalytic nature, one-electron step discharge and the rate-determining process between species of opposite charges.

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