Showing papers on "Polarography published in 1984"
TL;DR: In this article, the authors indique les procedes pour la mesure et le report des potentiels d'electrode dans des solvants non aqueux, vis-a-vis de ces systemes redox de reference.
Abstract: On montre que les couples redox ferrocene/ion ferricenium, [ferrocene: bis(η-cyclopentadienyl) fer(II)] et bis(biphenyl) chrome(I)/bis(biphenyl)-chrome(o) peuvent etre utilises comme systemes redox de reference. On indique les procedes pour la mesure et le report des potentiels d'electrode dans des solvants non aqueux, vis-a-vis de ces systemes redox de reference. Donnees numeriques obtenues dans 22 solvants organiques
1,168 citations
TL;DR: In this paper, the authors compared the electrode potentials of ferrocene/ferricenium ion and bis(biphenyl)chromium(O)/bis(biphippyl) chromium(I) ion for different solvents obtained by polarography and cyclic voltammetry.
137 citations
TL;DR: In this paper, a reduction current is obtained when an aqueous solution of copper and catechol is subjected to differential-pulse cathodic stripping voltammetry (d.p.c.a.s.).
125 citations
TL;DR: In this paper, the transfer of tetramethylammonium (TMA+) ion across the interface between LiCl aqueous solution and a 0.1 mol dm−3 tetrabutyammonium tetraphenylborate nitrobenzene solution was investigated by means of phase-selective a.c. polarography.
Abstract: The transfer of tetramethylammonium (TMA+) ion across the interface between a 0.1 mol dm−3 LiCl aqueous solution and a 0.1 mol dm−3 tetrabutylammonium tetraphenylborate nitrobenzene solution was investigated by means of phase-selective a.c. polarography. In recording the a.c. polarographic current a two-electrode cell system was used and the ohmic drop due to solution resistance in the cell was compensated for by positive feedback. The ion-transfer admittance vs. potential curves were determined in the a.c. frequency range between 10 and 100 Hz and the kinetic parameters of the TMA+-ion transfer across the water/nitrobenzene interface were determined.
96 citations
TL;DR: In this paper, the reduction current of adsorbed complex ions of vanadium is measured by differential pulse cathodic stripping voltammetry, preceded by a period of collection of a few minutes.
Abstract: Polarographic measurements showed that Catechol complexes of vanadium(V) adsorb onto the hanging mercury drop electrode. This property forms the basis of a sensitive eiectrochemical technique by which dissolved vanadium in seawater can be determined directly. The reduction current of adsorbed complex ions of vanadium is measured by differential pulse cathodic stripping voltammetry, preceded by a period of collection of a few minutes. The peak potential Is at --0.7 V. Optimal experimental parameters were found to be a catechol concentration of 2 X IO-* M, a collection potential of -0.1 V, and a soiutlon pH of 6.9. The limit of detection is 0.3 nM vanadium after a 2-min collection with a stirred soiutlon, which is decreased further to 0.1 nM after a 15-min collection.
92 citations
TL;DR: In this paper, the distribution of 1,10-phenanthroline and its derivatives between aqueous and 1,2-dichloroethane phases was investigated by investigating the faradaic ion transfer across a liquid-liquid interface using current scan polarography at the ascending water electrode, as well as by programmed current chronopotentiometry.
73 citations
TL;DR: In this article, the authors developed an equation for the pulse polarogram influenced by the reversible linear adsorption of a reactant of a reversible redox reaction on a stationary, planar electrode.
50 citations
TL;DR: Etude du mecanisme de transfert des ions Cd 2+, Zn 2+, Co 2+ et Ni 2+ a partir d'une phase aqueuse vers une solution de phenanthroline-1,10 (phen) dans du dichloroethane (DCE), par polarographie, en presence d'un electrode a eau ascendante as mentioned in this paper.
Abstract: Etude du mecanisme de transfert des ions Cd 2+ , Zn 2+ , Co 2+ et Ni 2+ a partir d'une phase aqueuse vers une solution de phenanthroline-1,10 (phen) dans du dichloroethane (DCE), par polarographie, en presence d'une electrode a eau ascendante
48 citations
TL;DR: In this article, the effect of adsorbates on the electrode kinetics of Eu3+/Eu2+ cannot be explained in terms of the inner-layer permittivity.
Abstract: Adsorption effects of ureas and thioureas on electrode kinetics were studied by using the electrode reactions of Zn2+/Zn(Hg) and Eu3+/Eu2+. The standard rate constant for Zn2+/Zn(Hg) is controlled by the inner-layer permittivity. The effect of this permittivity has been explained in terms of the solvent reorganization energy. The effect of the adsorbates on the electrode kinetics of Eu3+/Eu2+ cannot be explained in terms of the inner-layer permittivity. These two results suggest different locations for the formation of the activated complex: Inside the adsorption layer for Zn2+ and just outside layer for Eu3+.
38 citations
TL;DR: In this paper, the mechanism of electrodeposition of CdS on Hg and Pt electrodes has been studied in dimethylsulphoxide solutions by performing cyclic voltammetry at stationary electrodes and pulse polarography at dropping Hg electrodes in solutions containing both Cd(II) ions and elemental sulphur.
34 citations
TL;DR: Differential pulse polarography (d.p) was employed to study the interaction of copper(II) ions and carboxylic polysaccharides (pectate, P; algal alginate, AA; bacterial alginates, BA; gul(uronate)-rich oligomers, G; man(nuronate-rich oligomer, M), alternating man-gul oligomers and polyacrylate, PAA) in 0.05 M NaClO 4 aqueous solution as mentioned in this paper.
TL;DR: In this paper, the authors investigated the possible influcence of the adsorption induced capactive current on the total pulse polarographic current response, assuming that the electrode surface area is constant.
TL;DR: In this article, the basic analytical theory for NPP limiting currents affected by reactant adsorption is extended to the case of a spherical electrode and explicit expressions for the current are derived for the two limiting cases of a linear adaption isotherm and full coverage before pulse application respectively.
TL;DR: Conditional stability constants and complexation capacities of complexes between fulvic acid and lead, cadmium and copper have been determined by ion selective electrodes, dialysis and differential pulse anodic stripping voltammetry.
TL;DR: A simple polarographic assay for platinum determination in cis-dichlorodiammineplatinum(II)-DNA complexes is described, which makes it possible to determine the free (unbound) drug in the presence of DNA or platinum-DNA complex without a separation of free drug and macromolecular components of the solution to be analyzed.
TL;DR: Etude de la reduction de complexes η 5 -cyclopentadienyl-fer coordines a des cyclophanes a l'aide de la voltammetrie cyclique, polarographie, coulometrie et chronoamperometrie.
TL;DR: Etude par voltammetrie cyclique et polarographie as mentioned in this paper, voltamme disque tournant et polargraphie, mécanisme de reaction.
Abstract: Etude par voltammetrie cyclique, voltammetrie disque tournant et polarographie. Mecanisme de reaction
TL;DR: The electrochemical reduction of a number of 5-sulphadrug substituted-1,3-dimethylbarbituric acids has been studied by linear and cyclic sweep voltammetry, polarography and coulometric studies as discussed by the authors.
TL;DR: In this article, the reversibility of the oxidation process of p-aminophenol on a mercury electrode in buffered aqueous solutions was studied and differential capacity curves were recorded and the number of electrons was determined by chronoamperometry.
TL;DR: In this paper, it was shown that 0.2 M sodium fluoride solution is a superior medium for trace level determinations, and that the sensitivity in this medium is 0.64 nA (nmol l −1) −1 Cr(VI) at the 10-8M level.
Abstract: The polarographic determination of Cr(VI) is usually performed in a sodium hydroxide, ammonium tartrate or ammonium acetate supporting electrolyte. This study suggests that 0.2 M sodium fluoride solution is a superior medium for trace level determinations. With differential-pulse polarography, the sensitivity in this medium is 0.64 nA (nmol l–1)–1 Cr(VI) at the 10–8M level, and the detection limit is 1.6 × 10–8M Cr(VI). With 1 × 10–7M Cr(VI), 10-fold excesses of Fe(III), Cl– and NO3– do not change the current by more than 4%; Cu(II) causes an 8% decrease. The presence of Fe(III), Cu(II) and Cl– causes significant error with ammonium acetate and ammonium tartrate electrolytes.
TL;DR: In this paper, the authors used differential pulse polarography (DPP) for the determination of nivalenol (3α, 4β, 7α, 15-tetrahydroxy-12,13-epoxytrichotec-9-en-8-one).
TL;DR: In this paper, the electrochemical reduction mechanism of isophthalonitrile (1,3-benzenedicarbonitrile) has been investigated by cyclic voltammetry and polarography.
TL;DR: A method for the determination of chromium(VI) in water and waste water is described in this article, where chromium interference cations are separated by co-precipitation with aluminium from the phosphate-buffered solution.
TL;DR: Potentiometry and differential pulse polarography were used to determine stability constants of cadmium complexes with alanine, serine, valine and glutamic acid at 20 and 25±0.1°C in 0.70 M sodium perchlorate to simulate the ionic strength of seawater as discussed by the authors.
TL;DR: Under optimum conditions the wave-height is proportional to the concentration of zirconium in the range from 0 to 0.4 mug ml, and the serious interference from titanium(IV) can be effectively eliminated by solvent extraction with 3% tri-n-octylamine from lN sulphuric acid and stripping with 0.1 M perchloric acid-lM hydrochloric Acid-2M nitric acid mixture.
TL;DR: In this article, the results of reactions redox et d'echange des complexes de Hg avec des dithiocarbamates, Hg(RR'dtc) 2 dans du dichloroethane; (R=alkyl R' =alkyl ou aryl and dtc=dithiocalarbamate) ou HgL avec L=RR'd tc soit L=derive d'heterocycle azote=dtc
Abstract: Resultats d'etudes des reactions redox et d'echange des complexes de Hg avec des dithiocarbamates, Hg(RR'dtc) 2 dans du dichloroethane; (R=alkyl R'=alkyl ou aryl et dtc=dithiocarbamate) ou HgL avec L=RR'dtc soit L=derive d'heterocycle azote=dtc
TL;DR: In this paper, the reduction of the title complexes was studied by cyclic voltammetry in aqueous media, and the copper(I) dipeptide complexes were found to be short-lived and undergo transformations eventually generating Cu 0 at the mercury electrode.
TL;DR: The theory of the kinetic response in dc polarography and in normal pulse polarography for a system in which a chemical reaction is coupled to a charge-transfer reaction was developed in this paper.
TL;DR: In this paper, a method was proposed for the calculation of the rate constant of the intermediate chemical stage of an ECE mechanism, taking as a basis the study of the i −t curves obtained by dc polarography.