Polarography

About: Polarography is a research topic. Over the lifetime, 4772 publications have been published within this topic receiving 75478 citations.

Binding of Copper(II) to Pectins by Electrochemical Methods

Abstract: The interaction between Cu(II) and pectin extracted from citrus fruit was studied in KNO3 0.10 mol dm−3 at 25 °C and pH 5.5, using ion selective electrode potentiometry and voltammetry, namely differential pulse polarography and square-wave voltammetry. Although many independent variables may affect Cu(II)-polymer interactions such as charge density, polymer concentration and copper to polymer concentration ratio, a good fitting was observed for the model with ML and ML2 complex species, when M:L total concentration (mol dm−3) ratio varies from 0.2 to 2.7 and the ligand concentration is in the range (0.2 to 1) g dm−3, i.e., (0.4 to 2)×10−3 mol COO− dm−3. The complex parameters found in these conditions were log βCuL=3.5±0.1 and log βCuL2= 8.0±0.2. For lower total ligand and total metal ion concentrations, used in voltammetry, the interaction Cu(II)-pectin is affected by a cooperative mode (increase of metal ion-ligand affinity) when the total metal ion concentration increases and by an anti-cooperative mode when the total ligand concentration increases, possibly due to different conformations of the polymer.

Electrooxidation of COad Intermediated from Methanol Oxidation on Polycrystalline Pt Electrode

Abstract: The poisonous intermediate of methanol oxidation on a Pt electrode was validated to be CO(ad) by electrochemical method. An approximate treatment to bimolecular elementary reactions on an electrode was advanced and then was applied to the stripping normal pulse voltammetry (NPV) for complex multistep multielectron transfer processes on plane electrodes to study the kinetics of completely irreversible process of CO(ad) oxidation to CO2. The kinetic parameters for this process, such as standard rate constant (k0) and anodic transfer coefficient (alpha) for this irreversible heterogeneous electron-transfer process at electrode/solution interface and apparent diffusion coefficient (D(app)) for charge-transfer process within the monolayer of CO(ad) on electrode surface, were obtained with stripping NPV method. The effect of the approximate treatment on the kinetic parameters was also analyzed.