A general term which refers to a continuous layer, usually consisting of a semi-permeable
material, with controlled permeability
covering a structure, such as carbon or an inert
metal, or separating two electrolyte solutions. This latter case is the most general
form of an ion-selective electrode
. The membrane
separates the internal components of the ion-selective electrode from the test solution.
of an ion-selective electrode is responsible for the EMF response and selectivity
of the entire electrode. Comment: Membranes of sensor electrodes are thought to be
practically homogeneous, but an actual membrane
may contain inhomogeneous regions, often at surfaces, and connected with materials
and preparation methods used. Inhomogeneous regions include low dielectric polymer
regions with few charge sites and regions with high local site densities. Surface
regions of plasticized liquid membranes often are low in sites and high in plasticizer
or exuded impurities.
PAC, 1994, 66, 2527
(Recommendations for nomenclature of ionselective electrodes (IUPAC Recommendations
on page 2531
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by
A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997).
XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic,
J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. https://doi.org/10.1351/goldbook