Abstract: A test means for determining the ionic strength or specific gravity of an aqueous test sample, the test means comprising a weakly acidic or weakly basic polyelectrolyte which is at least partially neutralized, and an indicator means capable of producing a detectable response to ion exchange between the polyelectrolyte and the sample. The test device comprises a carrier matrix incorporated with the test means, and the method for its use comprises contacting an aqueous test sample with the device and observing a detectable response.

Abstract: A disposable biomedical electrode which includes a vaulted dome-like electrolyte-containing chamber or cavity bridged at its open bottom by a highly flexible and conformable microporous membrane, the latter being covered with an adhesively-secured protective film the film being strippable preparatory to adhesively securing the electrode to a body surface. The electrode material and shape are such that the vaulted housing is physically distortable upon downward pressure applied thereto, thereby to force the electrolyte to diffuse through the microporous membrane into positive and low-electrical-resistance contact with the skin surface of a subject.