Sensitivity and Selectivity of Ion-Selective Electrodes Interpreted Using the Nernst-Planck-Poisson Model

: Jasielec JJ, Mousavi Z, Granholm K, Sokolski T, Lewenstam A

Publisher: AMER CHEMICAL SOC

: 2018

: Analytical Chemistry

: ANALYTICAL CHEMISTRY

: ANAL CHEM

: 90

: 15

: 9644

: 9649

: 6

: 0003-2700

DOI: https://doi.org/10.1021/acs.analchem.8b02659

The Nernst-Planck-Poisson model is used for modeling the sensitivity and selectivity of ion-selective electrodes (ISEs) with plastic membranes. Two pivotal parameters characterizing ISE response are in focus: sensitivity and selectivity. An interpretation of sensitivity, which considers the concurrent influence of anions and cations on the ISE slope, is presented. The interpretation of selectivity shows the validity and limits of approaches hitherto taken to measure the true (unbiased) selectivity coefficient. The validity of more idealized interpretations by the diffusion-layer model is conceived.