Quasi-reversible Electrode Process Research Articles

Electroanalytical investigations—IV. use of orthogonal collocation for the simulation of quasireversible electrode processes under potential scan conditions

The method of orthogonal collocation is used to discretize the differential equations describing quasireversible electrode processes under conditions of potential scanning. The resulting set of ordinary differential equations is solved to give numerical simulations. The numerical values are compared to literature data. A method for optimization of the dimensionless parameter β is given.

Theoretical analysis of catalytic current—potential curves Part II. First-order regeneration reactions coupled with dimeric product of the electrode reaction

Equations of the polarographic current-potential curves are derived for electrode reactions of the type 2A+ze−ks,α→B coupled by an irreversible chemical regeneration reaction B+Ck→2A+D. Analytical solutions based on a general treatment were derived, including reversible, irreversible and quasi-reversible electrode processes. The kinetic domain over which an irreversible following chemical reaction affects the half-wave potentials is defined.

Theoretical analysis of catalytic current-potential curves: Part II. First-order regeneraration reactions coupled with dimeric product of the electrode reaction

Equations of the polarographic current-potential curves are derived for electrode reactions of the type 2A+ ze − k s,α →B coupled by an irreversible chemical regeneration reaction B+C k →2A+D. Analytical solutions based on a general treatment were derived, including reversible, irreversible and quasi-reversible electrode processes. The kinetic domain over which an irreversible following chemical reaction affects the half-wave potentials is defined.

Influence of amalgam formation in differential pulse polarography

The reversible reduction of Cd(II) in 1 M NaCl has been considered using theory based on digital simulation. Differential pulse peak currents and positions are influenced by amalgam formation coupled with spherical diffusion, and this is considered in relation to the results of previous investigations. Spherical diffusion is not experimentally significant except at short drop times where distortion arising from dc terms are present. For quasi-reversible electrode processes the influence of spherical diffusion and amalgam formation is demonstrated to be considerably more important than for the reversible case.

Theory of a.c. differential pulse polarography − a waveform for simultaneously obtaining d.c., a.c. and pulse polarograms

The theory for the technique of a.c. differential pulse polarography is presented. Since the waveform is a linear combination of d.c. differential pulse polarography and sinusoidal a.c. polarography the possibility of obtaining a wide range of electroanalytical responses at different time domains is considered. Advantages in analytical and kinetic investigations are discussed. Experimental data for reduction of cadmium in 1 M NaCl and zinc in 1 M KCl (pH 3.0) are presented. For the latter system the drop time and temperature dependence reveal anomalous behaviour showing the model of a quasi-reversible electrode process is inadequate.

Theory of a.c. differential pulse polarography — A waveform for simultaneously obtaining d.c., a.c. and pulse polarograms

The theory for the technique of a.c. differential pulse polarography is presented. Since the waveform is a linear combination of d.c. differential pulse polarography and sinusoidal a.c. polarography the possibility of obtaining a wide range of electroanalytical responses at different time domains is considered. Advantages in analytical and kinetic investigations are discussed. Experimental data for reduction of cadmium in 1 M NaCl and zinc in 1 M KCl (pH 3.0) are presented. For the latter system the drop time and temperature dependence reveal anomalous behaviour showing the model of a quasi-reversible electrode process is inadequate.

Numerical evaluation of complex stability constants from polarographic data for quasi-reversible processes

Stability constants of copper(II) butyrate complexes were determined by polarography. Numerical treatment of polarographic data for quasi-reversible electrode processes was developed and yielded good estimates of reversible E 1 2 values. An improved three-electrode polarographic apparatus was constructed based on operational amplifiers.

Logarithmic analysis of two overlapping d.c. polarographic waves IV. Quasireversible electrode processes

Logarithmic analysis of two overlapping d.c. polarographic waves IV. Quasireversible electrode processes

Logarithmic analysis of two overlapping D.C. Polarographic waves: IV. Quasireversible electrode processes

Summary The application of logarithmic analysis of two quasireversible overlapping d.c. polarographic waves is discussed. In this case, only the reversible part of the first quasireversible wave and the irreversible part of the second quasireversible wave can usually be separated from the original experimental logarithmic curve. One of the quasireversible waves can be completely constructed only in the case when the other is relatively small. The logarithmic analysis can also be applied to the anodic-cathodic quasireversible wave and a method for the determination of both transfer coefficients, reversible half-wave potential, and the corresponding rate constant of the electrode reaction is proposed.