In the analysis of fluoride levels, what property does the Ion Selective Electrode utilize?

The Ion Selective Electrode (ISE) specifically relies on an ion-specific response to measure fluoride levels. This means that the ISE is designed to selectively respond to fluoride ions in a solution while minimizing interference from other ions present. The electrode generates a potential (voltage) that is proportional to the concentration of fluoride ions, based on the Nernst equation. This potential difference is what enables accurate measurement of fluoride levels in drinking water.

In contrast, options like color change and electrical conductivity do not pertain to the functioning of ISEs in fluoride measurement. Colorimetric methods might involve color change to assess concentrations, but this is not how ISEs operate. Similarly, while electrical conductivity can provide information about the overall ionic content of a solution, it does not provide specificity for individual ions like fluoride. Temperature variation does play a role in many chemical processes but is not a principle utilized by ISEs for specific ion detection. Therefore, the ion-specific response is the crucial property that enables the accurate, selective measurement of fluoride concentration in water.