Patent ID: 8206567

Claim:
A reference electrode assembly containing an internal filling solution, comprising: an Ag/AgCl internal electrode formed of a silver rod having a lower tip end of AgCl; and an inner tube which houses, in order from a top side to a bottom side, the internal electrode, a first ceramic member, an inorganic cation exchanger, of a particulate powder of ZrO 2 , for trapping any silver ions leaching from the internal electrode, and a second ceramic member for preventing any diffusion of the silver ions to the internal filling solution which includes chloride, wherein said inner tube is immersed in the internal filling solution and seals directly to a side of the lower tip end of AgCl and to sides of the first ceramic member and second ceramic member while permitting access of the second ceramic member to the internal filling solution, wherein between the internal electrode and the inorganic cation exchanger, said inner tube houses the first ceramic member for inhibiting any leaching of the silver ions from the internal electrode to the inorganic cation exchanger.