A Reference Electrode with Free-Diffusion Liquid Junction for Electrochemical Measurements under Changing Pressure Conditions.

A reference electrode for electrochemical measurements under changing pressure conditions is presented. The electrode of the Ag,AgCl|KCl type incorporates a mechanical pressure equalizing system to achieve independence from ambient pressure. An open liquid junction in connection with a controlled electrolyte outflow ensures accurate in situ measurements over periods of up to 10 days. Abrupt pressure changes (0.1 MPa s(-1)) effected short-time, reversible peak potential changes of less than 1.3 mV. The system was successfully used to monitor gastric pH in diving animals. The advantages of the new design are high tolerance to pressure changes, small size, no memory effects, low susceptibility to junction contaminations, and a long operating life, even under repeatedly changing pressure conditions.