Solid-contact ion-selective electrodes (SC ISEs) find increasing application in analytical practice. Owing to several important properties such as convenience of operation and transportation and the absence of internal solution, which requires periodical regeneration, these electrodes are gradually replacing ion-selective film electrodes with liquid internal solution in ionometric analysis. Usually, ion-sensitive membranes of both types of electrodes are prepared similarly. They differ in some electrode properties such as selectivity, functioning limits, time of response, and potential stability. A study was conducted to determine whether electrodes with liquid filling and similar ISEs with a solid current lead actually differ in the concentration intervals of their functioning. (from Journal translation)