Ion sensor

An ion sensor having an ion selectivity, which comprises an internal solid electrode of metal/metal salt, comprising of an electroconductive layer of at least one metal and a layer of an insoluble salt of the metal in contact with the electroconductive layer, an ion selective membrane whose supporting membrane comprises a hydrophobic polymer, and an intermediate layer which keeps water molecules, provided between the internal solid electrode and the ion selective membrane, the intermediate layer comprises dried residues of an aqueous solution comprising a mixture of a hydrophilic polymer, an inorganic salt, an inorganic compound having a water-keeping property and an organic compound having a water-keeping property.

An ion sensor having an ion selectivity, which comprises an internal solid electrode of metal/metal salt, comprising an electroconductive layer of at least one metal and a layer of an insoluble salt of the metal in contact with the electroconductive layer, an ion selective membrane whose supporting membrane comprises a hydrophobic polymer, and an intermediate layer which keeps water molecules, provided between the internal solid electrode and the ion selective membrane, the intermediate layer comprises dried residues of an aqueous solution comprising an inorganic compound having a water-keeping property or an organic compound having a water-keeping property, a hydrophilic polymer and an inorganic salt, where the organic compound having a water-keeping property is selected from the group consisting of polymethylene glycol, polyethylene glycol and polypropylene glycol and has a molecular weight of 200 to 600, and the inorganic compound having a water-keeping property is selected from the group consisting of calcium chloride, gold chloride, magnesium perchlorate, magnesium fluoride and vanadium chloride dioxide.

An ion sensor having an ion selectivity, which comprises an internal solid electrode of metal/metal salt, comprising of an electroconductive layer of at least one metal and a layer of an insoluble salt of the metal in contact with the electroconductive layer, an ion selective membrane whose supporting membrane comprises a hydrophobic polymer, and an intermediate layer which keeps water-molecules, provided between the internal solid electrode and the ion selective membrane, the intermediate layer comprises dried residues of an aqueous solution comprising a hydrophilic polymer, an inorganic salt and a polymer of hydrazine derivative represented by the following chemical formula:

• ##STR3## where R and R' are hydrogen atoms, alkyl groups or hydroxyl groups and n>1.

An ion sensor having an ion selectivity, which comprises an internal solid electrode of metal/metal salt, comprising an electroconductive layer of at least one metal and a layer of an insoluble salt of the metal in contact with the electroconductive layer, an ion selective membrane whose supporting membrane comprises a hydrophobic polymer, and an intermediate layer which keeps water molecules, provided between the internal solid electrode and the ion selective membrane, the intermediate layer comprises dried residues of an aqueous solution comprising a chain compound or a cyclic compound having at least one double bond and containing at least one nitrogen atom, and a hydrophilic polymer.