Showing papers on "Polarography published in 1987"
TL;DR: Copper(II) appears to form stronger surface complexes with the high affinity ligands of the bacterial surface than with the functional groups of hydrous oxides, which indicates that metal ions bind first to the highest affinity surface ligands and subsequently to those of lesser activity.
92 citations
TL;DR: An analytical equation for stationary currentpotential curves at microdisk electrodes was derived by the Wiener-Hopf method when the electrode reaction is quasi-reversible and totally irreversible as mentioned in this paper.
70 citations
TL;DR: The interpretation of anodic stripping voltammetric (ASV) peaks for measuring the complexation reactions of metal ions with aquatic fulvic and humic compounds is difficult due to the simultaneous influence of several different phenomena, in particular the heterogeneous nature of fulvic compounds, the fact that the ligand is not in excess compared with the metal ion during the stripping step, the slow diffusion of the complexes compared with free metal ions, and the adsorption of Fulvic compounds on the electrode as mentioned in this paper.
68 citations
TL;DR: In this article, the theoretical treatment of square wave anodic stripping voltammetry at a mercury film electrode is presented, using the step method, showing that the dlfferentlal current voltammograms are symmetrical and the peak potentlal, E, shlfts to more negaflve potentials.
Abstract: The theoretical treatment of square wave anodic stripping voltammetry at a mercury film electrode Is presented. Numerlcal calculations, using the step method, show that the dlfferentlal current voltammograms are symmetrical and the peak potentlal, E,, shlfts to more negaflve potentials (anEd8 log A = 59.2 mV) with decreasing film thickness parameter A = / / ( D R ~ ) " * . For A 3 to 99 mV for A < 0.3.
59 citations
01 Jan 1987
TL;DR: Heterogeneous Potentiometric Enzyme Immunoassay for Antigens and Haptens with Iodide Selective Electrode and use of Immunochemical Separation and Electrochemical Detection in Flow Injection Analysis of Lactic Dehydrogenase.
Abstract: On the Direct Immunochemical Potentiometric Signal.- Selective Antibody Responsive Membrane Electrodes.- Electroimmunoassay of PGE2: An Antibody-Sensitive Electrode Based Competive Protein-Binding Assay.- Immuno-Potentiometric Sensors with Antigen Coated Membrane.- The Opsonized Electrode.- Homogeneous Voltammetric Immunoassay of Haptens.- Immunoassay by Differential Pulse Polarography and Anodic Stripping Voltammetry.- Separation-Free (Homogeneous) Amperometric Immunoassay Using an Apoenzyme as the Label.- Digoxin Homogeneous Enzyme Immunoassay with Amperometric Detection.- Antibody to an Enzyme as the Modulator in Separation-Free Enzyme Immunoassays with Electrochemical Sensor.- Immunochemical Determination of Creatine Kinase Isoenzyme-MB.- Immunosensor Based on Labeled Liposome Entrapped-Enzymes.- Measurement of Complement Fixation with Ion Selective Membrane Electrodes.- Antibody-Antigen Precipitin Reaction Monitoring with an Ion Selective Electrode.- Enzyme-Linked Immunoassay with a Fluoride Ion Selective Electrode.- Heterogeneous Potentiometric Enzyme Immunoassay for Antigens and Haptens with Iodide Selective Electrode.- Enzyme Immunoassay using the Ammonia Gas-Sensing Electrode.- Homogeneous and Heterogeneous Enzyme Immunoassays Monitored with Carbon Dioxide Sensing Membrane Electrode.- Enzyme-Linked Immunosorbent Assays Using Oxygen-Sensing Electrode.- Bioaffinity Electrochemical Sensor with Preformed Metastable Ligand-Receptor Complex.- Electric Pulse Accelerated Immunoassay.- Heterogeneous Enzyme Immunoassay with Amperometric Detection.- Enzyme Immunoassay in Flow Systems with Electrochemical and Other Detectors.- Use of Immunochemical Separation and Electrochemical Detection in Flow Injection Analysis of Lactic Dehydrogenase.- Rapid Subpicomole Enzyme Immunoassay by Flow Injection with Amperometric Detection.- Contributors.
49 citations
TL;DR: In this article, the authors investigated the stability and composition of the metal-Triton X complexes by changing the length of the oxyethylene chain of the TritonX, taking into account the ion-dipolar bond formation between metal ions and the polyoxyethylene chains.
49 citations
TL;DR: A reduction mechanism for the nitrofuran derivatives is suggested, in which the importance of the homogeneous chemical reactions associated with the electron-transfer steps is examined.
Abstract: In pyridine-formic acid buffer and tetramethylammonium chloride solution of pH 4.5 at a dropping mercury or a glassy carbon electrode, nitrofurazone, furazolidone and nitrofurantion are reduced in a single six-electron wave, while chloramphenicol and other structurally related nitro derivatives are reduced in only one four-electron wave, the nitro group being reduced to the amine or to the hydroxylamine, respectively. The electrochemical behaviour of these compounds depends mainly on the nature and position of the substituents. Reduction to the primary amine occurs when the substituents possess available π electrons to conjugate with the nitro group of the aromatic ring, which determines the transformation of the hydroxylamine into the amine via formation of a highly reducible intermediate imine or a quinonoid structure. In contrast, if the formation of the intermediate imine is made impossible by an adverse effect of the substituent, the hydroxylamine does not undergo further reduction.Cyclic voltammograms were recorded at different pH values and at different scan rates in order to identify certain relatively unstable species. The effect of pH on the diffusion-limited current and on the E½ values of the polarographic waves was also studied and the results obtained were compared with those obtained by cyclic voltammetry.On this basis, and according to the polarographic and cyclic voltammetric data, a reduction mechanism for the nitrofuran derivatives is suggested, in which the importance of the homogeneous chemical reactions associated with the electron-transfer steps is examined.
46 citations
TL;DR: Benzyliminodiacetic acid, pyridine 2,6-dicarboxylic acid and Pb and Cd complexes were studied by normal pulse polarography, in a low concentration range as mentioned in this paper.
45 citations
30 citations
TL;DR: The electrochemical behavior of midazolam [7-chloro-5-(o-fluorophenyl)-3H-(2′- methyllimidazo) [1,5-a]-benzodiazepine was studied by polarography and cyclic voltammetry as discussed by the authors.
29 citations
Book•
24 Sep 1987
TL;DR: In this paper, a qualitative and quantitative analysis of Metallic Cations Electrodes other than DME Solvent/pH for organic analysis complexation in Inorganic Analysis Sampled DC Polarography AC Polarography Pulse Polarographic Methods Stripping Voltammetry The Analyst and Polarography: Criteria for Choice of Polarographic Mode Interference and Matrix Effects
Abstract: Classical DC Polarography: Circuitry Cell Design The Dropping Mercury Electrode (DME) Solution Conditions Theory and Form of Current/Potential Relationship Qualitative and Quantitative Analysis of Metallic Cations Electrodes other than DME Solvent/pH for Organic Analysis Complexation in Inorganic Analysis Sampled DC Polarography AC Polarography Pulse Polarographic Methods Stripping Voltammetry The Analyst and Polarography: Criteria for Choice of Polarographic Mode Interference and Matrix Effects.
TL;DR: In this paper, the electrochemical behavior of dacarbazine was investigated by Tast and differential pulse polarography (d.p.) at the dropping mercury electrode, by cyclic and differential pulses voltammetry at the hanging mercury drop electrode and by anodic voltammetric at the glassy carbon electrode.
TL;DR: In this paper, the electrochemical reaction Cd 2+ + 2 e − = CD(Hg) was studied in dimethylsulfoxide containing tetraethylammonium perchlorate as a supporting electrolyte, using dc polarography, ac admittance measurements, cyclic voltammetry with convolution and chronoamperometry.
TL;DR: The interference of Cl- with the cathodic stripping signals is only evident at concentrations of Cl– four orders of magnitude higher than the concentration of the drug and uric acid was found not to interfere at up to equal concentrations of 5-fluorouracil.
Abstract: An investigation has been carried out into the anodic differential-pulse polarographic and cathodic stripping voltammetric behaviour of the anticancer drug 5-fluorouracil at mercury indicator electrodes. The anodic peak, corresponding to the formation of a mercury salt, has been used for the determination of the drug in formulations with a relative standard deviation of 0.5%. The cathodic stripping voltammetric behaviour of this mercury salt can be used to monitor 10–7–10–8M concentrations of 5-fluorouracil in a borax-HClO4 buffer, pH 7.8. The interference of Cl– with the cathodic stripping signals is only evident at concentrations of Cl– four orders of magnitude higher than the concentration of the drug and uric acid was found not to interfere at up to equal concentrations of 5-fluorouracil. The cathodic stripping method has been applied to the determination of 5-fluorouracil in human serum.
TL;DR: In this paper, the reduction of several dialkylpyrrolidinium cations and tetramethylammonium at mercury cathodes was investigated, and the data obtained from polarography and from cyclic voltammetry at mercury film cathodes showed that the process involves fast one-electron transfer per R4N+ and results in the generation of solid ordered films.
TL;DR: A. K. Jordan (USA), K. C. Izutsu (Japan), and K. Tóth (Hungary) as discussed by the authors have been elected to the board.
Abstract: Chairman: J. Jordan (USA); Secretary: K. Izutsu (Japan); Titular Members: A. K. Covington (UK); J. Juillard (France); R. C. Kapoor (India); E. Pungor (Hungary); Associate Members: W. Davison (UK); R. A.. Durst (USA); M. Gross (France); K. M. Kadish (USA); R. Kalvoda (Czechoslovakia); H. Kao (China); Y. Marcus (Israel); T. Mussini (Italy); H. W. Nurnberg (FRG); M. Senda (Japan); N. Tanaka (Japan); K. Tóth (Hungary); National Representatives: D. D. Perrin (Australia); B. Gilbert (Belgium); W. C. Purdy (Canada); A. A. Vlek (Czechoslovakia); H. Monien (FRG); M. L'Her (France); Gy. Farsang (Hungary); H. C. Gaur (India); W. F. Smyth (Ireland); E. Grushka (Israel); S. R. Cavallari (Italy); W. Frankvoort (Netherlands); Z. Galus (Poland); G. Johansson (Sweden); J. Buffle (Switzerland); H. Thompson (UK); J. G. Osteryoung (USA); I. Piljac (Yugoslavia).
TL;DR: In this paper, a voltammetric method for the determination of 3-mercapto-D-2-methylpropanoyl-L-proline, a hypotensive drug whose pharmaceutical name is Captopril (CPT), in the concentration range from 9.0×10 −10 M to 3-10 −6 M, is described.
TL;DR: In this article, the mechanism of cathodic reduction of ethyl-, butyl-, and decyl iodide at mercury and carbon electrodes in acetonitrile solutions was investigated using reverse pulse polarography (RPP) and other voltammetric techniques together with coulometry.
TL;DR: In this paper, the electrochemical behavior of bilirubin on a mercury electrode in aqueous solution at physiological pH was investigated by differential pulse polarography, and two polarographic peaks at about − 1.30 and −1.42V versus s.c.
TL;DR: The mechanism of the electrode reaction of the Eu(III−EDTA/Eu(II)-EDTA system in the mixed solvents used was compared with that of non-complexed solvated europium ions in these media.
TL;DR: In this paper, the rate constants of the electrode reaction V(III)+e− → V(II) in water+acetone mixtures were determined using polarographic and square wave polarographic measurements, respectively.
TL;DR: In this paper, a new method for the measurement of the concentration of humic substances (HS) in seawater is described, based on differential cathodic sweep voltammetry.
Abstract: A new method for the measurement of the concentration of humic substances (HS) in seawater is described. The peak obtained by differential cathodic sweep voltammetry after HS adsorption in the presence of traces of molybdenum(VI) can be used for quantitative determination. Measurements using various electrochemical techniques (ACP, CV, ADPV, DPP) would indicate that the film adsorbed onto the electrode is the result of the adsorption of the organic substance in a first step followed in a subsequent step by the formation of a surface complex (Mo(VI)-HS)ads rather than the direct adsorption of the dissolved complex. The electrochemical mechanism corresponds to a one-electron reduction of the adsorbed (Mo(VI)-HS)ads complex to the corresponding (Mo(V)-HS)ads complex.
TL;DR: Direct current polarography and cyclic voltammetry were used to study tamoxiphene, clomiphene (CM), and chlorotrianisene (ChT) as discussed by the authors, and the dependence of the limiting currents and half-wave potentials on the pH of solution, temperature, mercury head, ionic strength and surface tension of the solution were studied.
TL;DR: In this paper, the current-potential curves of an EE mechanism in Normal Pulse Polarography have been derived rigorously for the cases where (a) both steps are reversible, (b) one is reversible and the other irreversible, and (c) both are well separated.
TL;DR: In this paper, l'adsorption du bipyridyle-4,4', a partir de solutions salines aqueuses, sur une electrode de mercure.
Abstract: Etudes de l'adsorption du bipyridyle-4,4', a partir de solutions salines aqueuses, sur une electrode de mercure. Donnees, aussi, sur sa reduction
TL;DR: In this paper, a reliable differential pulse polarographic method is described for the determination of cyanuric acid (1,3,5-triazine-2,4,6-triol) in pool water.
TL;DR: In this article, the half-wave potentials of reversible polarographic or voltammetric waves were determined by performing a log plot analysis on experimental current data using planar electrodes.
TL;DR: In this article, anion-chromatography with polarographic detection was examined for separation of alkaline mixtures of inorganic sulfur compounds and polysulfide (S 2− x ) was concluded to undergo dissociation to S 2− and S°.