Showing papers on "Polarography published in 1977"
TL;DR: In this article, the basic equations for current-electrical potential difference across the interface have been deduced for the cases of ion as well as electron transfer for various base electrolyte systems.
208 citations
TL;DR: In this article, the theoretical aspects of square voltammetry at the dropping mercury electrode are presented, which involves scanning the entire potential range of interest on a single drop of a dme.
Abstract: : The theoretical aspects of square voltammetry at the dropping mercury electrode are presented. The technique involves scanning the entire potential range of interest on a single drop of a dme. Asymmetries in the waveform as well as variations in current measurement parameters are discussed. Indications are that previous uses of the waveform may not have utilized all its capabilities.
150 citations
TL;DR: A polarographic study of the oxidation mechanism of L-ascorbic acid and of the reduction mechanism of dehydro-Lascorbics was carried out in an acid medium as mentioned in this paper.
Abstract: A polarographic study of the oxidation mechanism of L-ascorbic acid and of the reduction mechanism of dehydro-L-ascorbic acid was carried out in an acid medium.For L-ascorbic acid, the oxidation pr...
120 citations
TL;DR: In this paper, a trace analysis using square wave voltammetry at the dme is presented, which is shown to have the same order of sensitivity as differential pulse polarography but is much faster to perform.
Abstract: : Experimental verification of earlier theoretical work for square wave voltammetry at the dropping mercury electrode is given. Experiments using ferric oxalate and cadmium (II) in HC1 confirm excellent agreement with theory. Experimental peak heights and peak widths are found to be within 2% of calculated results. An example of trace analysis using square wave voltammetry at the dme is presented. The technique is shown to have the same order of sensitivity as differential pulse polarography but is much faster to perform. A detection limit for cadmium in 0.1 M HC1 for the system used here was 7 x 10 to the minus 8th power M.
80 citations
TL;DR: The adsorption behavior and reducibility of MetHb, MetMb and cytochrome c were characterized by the concentration and by the drop-time dependence of the decrease in relative capacitance in a.c. polarograms, pulse polarography and macroscale electrolysis as discussed by the authors.
70 citations
TL;DR: In this article, the results of polarographic studies on the Cu(II)-thiourea-2M H2SO4 and equilibria resulting in that system are presented.
65 citations
TL;DR: In this paper, the authors applied simulation techniques to the diagnosis of the ways in which the peak currents and wave shapes of differential pulse polarograms are affected by the adsorption of reactants or products.
64 citations
63 citations
TL;DR: Using AC polarography on a stationary mercury electrode and transferring the electrode covered with an adsorbed protein into another protein solution possessing a greater electrochemical activity, it was established that the exchange of the protein from the first layer does not occur and that the same monolayer of flattened protein develops both at large and small concentrations as discussed by the authors.
63 citations
TL;DR: In this paper, a phase-sensitive polarization (PSP) and oscillographic and pulse polarisation (OPP) was used to study the discharge of coenzymic groups and metals.
58 citations
TL;DR: In this article, an equation was derived which enables the determination of stability constants of complex ions by differential pulse polarography, and values obtained by this method for the cadmium (II) chloride system were in excellent agreement with those determined by potentiometry using a cad mium amalgam electrode.
TL;DR: In this article, the deposition stripping behavior of iodide films at the hanging mercury drop electrode (HMDE) was investigated, and the surface monolayers of Hg. HgI and Hg/sub 2/I/sub 3/2/sub 4/1/2.
Abstract: The deposition-stripping behavior of iodide films at the hanging mercury drop electrode (HMDE) is investigated. Surface monolayers of Hg . HgI and Hg/sub 2/I/sub 2/ are postulated based on the percentage occupancy of the available sites at the surface of the HMDE. Submonolayer films of Hg . HgI, as stripped from the electrode, are used to determine iodine concentrations from 1 to 50 ppb with a standard deviation of 0.3 ppb.
TL;DR: In this paper, the effect of neutral organic surfactants on charge transfer at a fully covered dropping mercury electrode has been investigated by the polarographic technique, and it was shown that the percentage decrease in the charge transfer rate constant caused by the surfactant does not depend upon the adsorptivity.
TL;DR: In this article, the titration of micromolar levels of complexing agents with metal ion titrants, and voltammetric methods to locate the equivalence point, has been evaluated experimentally and theoretically.
TL;DR: Unter Verwendung einer Mikroelektrode, hergestellt aus feinem Pt-Draht in einer Glasrohre, ist es moglich, di?nierte Redoxpotentiale von aromatischen Kohlenwasserstoffen wie z.B. Perylen und 1,2-Bis-[anthranyl-(9)]-athan in den Titellosungsmitteln zu messen.
Abstract: Unter Verwendung einer Mikroelektrode, hergestellt aus feinem Pt-Draht in einer Glasrohre, ist es moglich, di?nierte Redoxpotentiale von aromatischen Kohlenwasserstoffen wie z.B. Perylen und 1,2-Bis-[anthranyl-(9)]-athan in den Titellosungsmitteln zu messen.
TL;DR: Direct-current polarographic studies of the wave characteristics indicate that it is of the catalytic hydrogen type, sensitive to pH changes, temperature, and electrode characteristics, and shown to suffer little interference from other platinum-group metals at 1:1 concentration ratio to Pt.
TL;DR: In contrast to results from aqueous solution, the initial one electron reduction proceeds with a rapid loss of cyanide to give the blue five-coordinate tetracyanonitrosylferrate(I) anion.
Abstract: : The electrochemical reduction of the pentacyanonitrosylferrate(II) anion has been studied in nonaqueous aprotic media by polarography, cyclic voltammetry and coulometry. In contrast to results from aqueous solution, the initial one electron reduction proceeds with a rapid loss of cyanide to give the blue five-coordinate tetracyanonitrosylferrate(I) anion. The tetracyanonitrosylferrate(I( anion undergoes a further quasireversible reduction and an oxidation which is reversible at fast sweep rates.
TL;DR: In this paper, the capacitance curves of inosine, xanthosine and 6-azauridine at pH 7 were determined by means of B reyer's alternating current polarography.
TL;DR: In this paper, the electrochemical properties of the compounds NbnW6−nO19(2+n)− were studied by polarography, controlled potential electrolysis and cyclic voltammetry on the mercury electrode.
TL;DR: The denaturation of the two forms of ferredoxin is studied by polarography in conjunction with UV spectrophotometry and two new peaks at negative potentials before the reduction of the solvent are observed in denaturated proteins.
TL;DR: In this article, a new approach was developed for discriminating at the dropping mercury electrode (DME) between currents controlled by various types of rate processes, including diffusion and chemical kinetics of reactions coupled with electron transfer.
TL;DR: From polarographic and voltammetric measurements using carrier concentrations of the long lived isotope 99Tc, appropriate ranges of electrode potential for electrolytic reduction were determined and reaction conditions were predicted and experimentally confirmed for the electrolytic labelling of tetracycline and EDTA with carrier free 99mTc.
TL;DR: In this article, a 10 μM solution of adenine in pH 4.8 mcilvaine buffer (0.5 M ionic strength) on d.c. polarography, normal pulse polarography and rapid scan-rate cyclic voltammetry was analyzed.
TL;DR: In this paper, an apparatus is described which allows one to measure the polarographic currents of free H atoms produced radiation chemically in an aqueous solution under 50 atm of hydrogen.
Abstract: An apparatus is described which allows one to measure the polarographic currents of free H atoms produced radiation chemically in an aqueous solution under 50 atm of hydrogen. The electrode was a tiny mercury drop. The polarogram of the H-atom contains a weak anodic wave and two cathodic waves. The pH dependence of these waves is described and electrode processes are attributed to the waves.Methyl and ethyl radicals were also produced in solutions under high methane or ethane pressure as well as the 2-hydroxyethyl radical in an ethylene + N2O containing solution. All these radicals have separated anodic and cathodic waves. The anodic wave is shifted towards more negative potentials in alkaline solutions. In acid solution additional cathodic currents were obtained in the potential range between the two main waves. Various electrode reactions of these organic radicals are discussed.
TL;DR: In this paper, it was shown that natural ribonucleic acids, as transfer, ribosomal and viral RNAs yield derivative pulse-polarographic peaks; from their heights and potentials conclusions can be made about their content of ordered structure in solution.
TL;DR: In this paper, a method for the determination of trace amounts of uranium (down to 10 µg l 1 ) in natural waters by differential-pulse polarography of a cyclohexane-trioctylphosphine oxide extract is described.
Abstract: A method is described for the determination of trace amounts of uranium (down to 10 µg l–1) in natural waters by differential-pulse polarography of a cyclohexane-trioctylphosphine oxide extract. Studies on the effect of possible interferences are included.
TL;DR: In this paper, the electrochemical reduction of cyclohex-2-enones was studied by means of cyclic voltammetry, d.c. polarography, coulometry and chemical product analysis.
Abstract: The electrochemical reduction of the cyclohex-2-enones 1a–1e (mercury cathode, CH3CN, Bu4NBF4) was studied by means of cyclic voltammetry, d.c. polarography, coulometry and chemical product analysis. Compounds 1a–1c give a mixture of the hydrodimers 4 and 5via formation of the radical anion 2 by an irreversible one electron transfer, followed by protonation and dimerization of the allylic radical 3. The 6-halocyclohex-2-enones 1d and 1e exhibit two distinct reduction waves. The first corresponds to an irreversible two electron transfer with formation of the halide anion and the enolate anion 6 which gives 1b by protonation. The second wave corresponds to a quasi-reversible one electron transfer to 6 to afford the radical dianion 7 (Scheme 2).