Determination of cadmium in the presence of indium by polarography with addition of an electroinactive surfactant

Abstract

Cadmium can be determined in the presence of a large amount of indium when the surfactant, Montanox 80, is added to the bulk solution at pH 2. The indium wave disappears when sufficient Montanox 80 is present, while the cadmium wave is shifted to more negative potentials and becomes more irreversible. Classical, differential pulse and a.c. polarography are compared; all are suitable for routine work. The detection limits are about 10 −6 M cadmium for 5 × 10 −3 M of indium in the presence of 10 −3 M Montanox 80.