PURPOSE: To obtain a long life ion sensor generating no delamination of an ion responsive film, in forming the ion responsive film to the inner peripheral surface of the through-hole provided to an insulating board, by providing polyvinyl chloride (PVC) resin plates provided with through-holes to both sides of the insulating board.
CONSTITUTION: A through-hole 12 is provided to an insulating board 11 comprising an epoxy resin disc and a Ag-layer 13 is formed to a part of the inner peripheral surface of said through-hole 12 while a AgCl-layer 14 is formed to the surface layer 13 by an electrolytic process and an ion responsive film 16 is formed so as to cover the layer 14 and the inner peripheral surface of the insulating board 11. In this case, recessed parts are formed to both sides of the insulating board 11 around the through-hole 12 and polyvinyl chloride resin rings 15, 15 having through-holes are inlaid with the recessed parts while the responsive film 16 consisting of ion selective substances, a plasticizer and a PVC resin is formed so as to cover the surfaces of the rings 15, the surface of the insulating board 11 and the layer 14. By this method, K+, Na+ and Cl--selective electrodes 31, 32, 33 are formed and received in a case along with a similarily fabricated reference electrode 34 through an insulating material. By this method, a small long life flow communication type sensor capable of simultaneously measuring ions in serum is obtained.
SUGANO KENICHI
KOYAMA MASAO
TAKIGUCHI TOSHIO
