Abstract: An electrochemical combination electrode assembly having an inner, tubular glass pH electrode body supported within a tubular outer plastic container, a reference electrolyte reservoir defined in an annular space between the container and the glass electrode, and an annular, pressure contact leakage junction defined between an inclined surface and edge on the glass electrode body and plastic container for establishing electrolytic communication between the reference electrolyte and a test solution. Preferably the leakage junction is established at the junction line of an axially tapering exterior surface of the glass electrode body and a circular edge on the plastic container surrounding the tapered surface. The glass electrode is nested in the plastic container until the tapering surface and circular edge engage. The degree of pressure engagement establishes the flow rate through the junction.

Abstract: An electrochemical combination electrode assembly particularly adapted for measuring the pH of body portions of a living subject, such as skin, hair, and the like, and which can be operated in any vertical, inclined or horizontal orientation. The assembly comprises a pH-indicating glass electrode supported within a tubular plastic container and includes a generally flat, pH-sensitive structure at a sensing end of the assembly. Conventional indicating and reference half-cell electrodes are supported in separate reservoirs of the assembly containing internal and reference electrolytes, respectively. The upper ends of the reservoirs are sealed by elastomeric plugs which compensate for differing coefficients of expansion within the assembly and coact with the electrolytes to prevent formation and migration of air bubbles to the sensing end of the assembly.