| 摘要 |
PROBLEM TO BE SOLVED: To restrict a mixture of heavy metal elements into a generated silver halide layer and correctly determine a specific ion activity by oxidizing a surface of a silver layer by a chelated iron (III) salt in the presence of a halide. SOLUTION: In order to halogenate a silver layer surface, a nonconductive supporting body coated with silver is dipped in a reaction bath with a chelated iron (III) salt and a halide. A concentration of the iron salt in the reaction bath is preferably in the range of 100-500 mM and more preferably in the range of 150-250 mM. After the dipping, the supporting body is washed with water and dried. A chelating agent used is preferably an amino-carboxylic acid compound such as propanediamine tetraacetic acid(PDTA), ethylenediamine tetraacetic acid(EDTA) or the like. Mixture of heavy metal elements (e.g. iron element) in the silver halide is nearly avoided and effects of interfering ions included in a sample can be eliminated. |
