Separation and spectrophotometric determination of palladium and platinum with dithizone using and iodide medium

Abstract

A method for the separation of palladium and platinum has been developed and the optimum conditions (dithizone and iodide concentration, acidity and shaking time) have been established. Platinum is not extracted from an iodide medium in the presence of sulphite at pH 3–5. The extraction of platinum follows after oxidation of sulphite with iodate and an increase in acidity. Interferences from mercury, gold, silver, copper and bismuth can be avoided by the masking action of the iodide and EDTA. Trace amounts of palladium in the form of a sparingly soluble palladium iodide are separated from the large amounts of platinum by flotation with benzene. The proposed method has been applied to the determination of palladium (7 p.p.m.) in high-purity platinum.