Ion responsive probe

An ion sensing probe for measuring the ionic characteristics of a liquid solution comprising:

• a tubular outer housing constructed of an epoxy plastic, a first electrode located within said outer housing and extending partially beyond one end of said outer housing, said first electrode including a tubular member constructed of an epoxy plastic and having a generally uniform outside diameter terminating at one end in a necked down portion having a reduced outside diameter, an annular platinum band located about said necked down portion, said platinum band having an installed outside diameter substantially the same as said uniform outside diameter whereby a generally continuous outer surface is provided by said platinum band and the adjacent portion of said tubular member, a first lead wire which is substantially silver connected to said platinum band and extending into said tubular member via an opening in said necked down portion, an insulating tube constructed of an epoxy plastic and located in clearance relationship within said tubular member and extending from substantially said necked down portion to a position outwardly of the opposite end of said tubular member, said first lead wire extending through said insulating tube and outwardly therefrom, the space between said insulating tube and said tubular member being filled with an epoxy plastic at least in the area of said necked down portion to seal the interior of said insulating tube from the solution being measured, a porous junction of polytetrafluoroethylene sealingly located at said one end of said outer housing, said tubular member of said first electrode sealingly located in an opening in said porous junction with said platinum band located beyond said one end of said outer housing, a reference electrode located within said outer housing, said outer housing filled with an electrolyte to at least partially immerse said reference electrode.