SILVER/SILVER HALIDE REFERENCE ELECTRODE, ITS FORMATION AND ION-SELECTIVE ELECTRODE

PROBLEM TO BE SOLVED: To avoid mixture of heavy metal elements into a silver halide layer and correctly determine the activity of specific ions in a sample by using an oxidizing agent which does not influence silver halide generated. SOLUTION: A silver halide layer is formed by oxidizing a surface of a silver layer with a peroxide in the presence of a halide. At this time, if the used peroxide is, for example, hydrogen peroxide, the silver layer can be uniformly oxidized because the hydrogen peroxide foams severely during the reaction. Moreover, heavy metal elements originated from the oxidizing agent are prevented from being included in the silver halide because the hydrogen peroxide is dissolved to oxygen and water. The ion-selective electrode with an ion selectivity applied to the silver/halide silver reference electrode shows superior electrical responsivity.