Ion-selective electrode in which the
ion-selective membrane is a crystalline material prepared from either a single compound or homogeneous mixture of compounds.
Example: A pressed membrane of \(\ce{Ag2S}\) used in an ISE for measurement of activities of silver ions or sulfide ions.
Source:
PAC, 2020, 92, 641. 'Terminology of Electrochemical Methods of Analysis (IUPAC Recommendations 2019)' on page 662 (https://doi.org/10.1515/pac-2018-0109)