Use of ligand buffers in the determination of the stability constants of metal complexes with ion-selective electrodes.

概要

論文の詳細を見る
The potential response of copper(II), lead and cadmium ion-selective electrodes was studied in ligand buffers which contain a complex ML(M:Cu2+, Pb2+ or Cd2+), a ligand L and an excess of a second metal N. By measuring [M] with the ion-selective electrode, the ratio of the stability constants, KML/KNL was determined. The effects of pH, the second metal ion N and the ratio of [N]/[NL] on the electrode response were studied in detail. The KML/KNL values obtained for EDTA were in good agreement with those calculated from KML and KNL in the literature. The stability constants of N-hydroxyethylenediamine-N, N′, N′-triacetate complexes were determined successfully. These logarithmic values of KNL were found: Pb2+, 15.59; Zn2+, 14.59; Co2+, 14.49; Cd2+, 14.24; Mn2+, 11.41. These results show that the method is very useful for the determination of the stability constants of complexes with metal ions for which suitable ion-selective electrodes are not available.
社団法人日本分析化学会の論文