Miniaturized solid-state reference electrode with self-diagnostic function

Abstract

The present invention relates to a reference electrode for a potentiometric electrode system, characterized in that the junction in contact with a sample solution is enlarged and an ion-sensitive membrane containing an ion selective material as a protective membrane for the inner reference solution is employed, which comprises a substrate; a metal layer; an insoluble metal salt layer; an insulating film for insulating the metal layer from an aqueous solution; a hydrogel serving as an inner reference solution; the junction on the hydrogel contacting with a sample solution; the ion-sensitive, protective membrane formed over all surface areas of the hydrogel, except for the junction, to separate the sample solution from the inner reference solution or act as an ion-sensing membrane upon the contamination of the junction, whereby the operational abnormality caused by junction contamination may be easily checked and fast activation may be achieved.

Dependencies are inferred from the claim text.