Related Experiment Video
Updated: Jun 28, 2026

Introduction to Solid Supported Membrane Based Electrophysiology
Published on: May 11, 2013
Interpretation of selectivity coefficients of solid-state ion-selective electrodes by means of the diffusion-layer
1Institute of Fundamental Problems in Chemistry, The University, Warsaw, Poland.
Abstract:
On the basis of a diffusion-layer model the selectivity coefficients of solid-state electrodes have been interpreted. In the Nernst equation the concentration of the principal ion may be expressed in terms of the diffusion coefficients D(B), D(C) and the equilibrium constant K of the reaction AB + C right harpoon over left harpoon AC + B where AB represents the membrane material and C the interfering ion, in the form of an equation: [B](0)=KD (B)KD (B) + D (C)[B] + KD (C)KD (B) + D (C)[C] where the concentration with subscript "0" denotes the surface concentration directly influencing the electrode potential, and [B] and [C] are bulk concentrations of the species indicated. The differences between various literature data can be explained on the basis of this model.
Related Concept Videos
Potentiometry: Membrane Electrodes
The Electrical Double Layer
Theories of Dissolution: Diffusion Layer Model
This process starts with a thin layer, saturated with the drug, forming at the interface between the solid and liquid. The solute then diffuses from this layer into the main solution. The Noyes-Whitney equation suggests that the rate of dissolution relies on the diffusion...
The Debye–Hückel Theory of Electrolyte Solutions
Processes at Electrodes
Debye–Huckel–Onsager Conductance Equation

