Glass Electrode
An ion-selective electrode whose thin glass membrane develops a potential proportional to the pH of the solution.
Formula / equation
E = constant − 0.0592 pH
Unit
V
In depth
Hydrogen ions exchange with sodium ions in the hydrated gel layer on the glass surface, creating a membrane potential that follows the Nernst equation. The electrode must be calibrated against standard buffers and kept hydrated, and it drifts at very high pH because of alkaline error.
Examples in the real world
The sensing element of every laboratory pH meter, combined with a reference electrode in one body.