An Application of a Porous Charcoal Junction to a Reference Electrode in Acidic and Alkaline Solutions

Charcoal is used as a salt bridge at the end of the Ag/AgCl reference electrode in acid and alkaline solutions. The impedance and the phase shift of the Ag/AgCl wire with the use of the charcoal junction are stable in all solutions, while those with the use of the glass frit show instability in the strong acid and alkaline solutions. Electrochemical impedance spectroscopic results on type 304 stainless steel surfaces are successfully obtained using the reference electrode with the charcoal junction, while the glass frit in strong acid and alkaline solutions shows inconsistency on the steel surfaces.