Electrochemical cell

Claim 1

A cell for electrochemical analysis of a constituent in a sample comprising: an electrically nonconductive body having an electrolytic reservoir therein, said electrolytic reservoir containing an electrolyte; a pair of spaced electrodes, a first of said electrodes being positioned within said reservoir in contact with the electrolyte filling said reservoir; an opening defined in said body to provide a passageway between said reservoir and the exterior of said body; means closing said opening including a porous material in contact with the electrolyte in the reservoir and providing a path for electrolyte diffusion therethrough; said porous material comprising the sole path for transfer of electrolyte from the reservoir to the exterior of the body; means mounting a second of said electrodes on the exterior of the reservoir within the perimeter of said opening adjacent said porous material and being electrically coupled with the first electrode through electrolyte carried through the porous material; a thin, flexible polymeric membrane permeable to both said constituent and said electrolyte overlying said porous material and said second electrode; and cover means overlying said membrane and providing an opening through which the constituent contacts the membrane, the interchange of the constituent and the electrolyte thereby being restricted by said porous material.