Glass Membrane Electrode

 

Glass Membrane Electrode

A glass membrane electrode is a type of selective ion electrode. This is made up of a glass membrane which allows only a specific ion to pass through it.

An example of a Glass membrane electrode is pH measurement. In the pH electrode, it allows only H⁺ ions to pass through it. This is used to detect the pH of different materials.

These electrodes are formed by doping molten SiO₂ with different chemicals, The H⁺ from the solution gets exchanged with Li in the glass. Thus, different glass composition helps us to measure Na⁺, Ag⁺, K⁺, and NH_4.

On immersing the glass electrode, in a solution a hydrated gel layer formed causing swelling of the membrane. 

The ion exchange process takes place in a glass membrane and generates a phase boundary potential.

E_gl  =    E^o_gl   + 0.0591    log₁₀ (Mⁿ)

(Mⁿ)  = concentration of ion of interest in the solution.