Selective complexometric determination of palladium(II) using DL-methionine as a selective masking agent

Abstract

A selective complexo-titrimetric method is described for the determination of palladium, DL-methionine being used as a masking agent. Palladium present in a given sample solution is first complexed with a known excess of EDTA and the surplus EDTA is titrated against zinc sulfate solution at pH 5.0–5.5 (acetic acid–sodium acetate buffer) using Xylenol Orange as indicator. A known excess of DL-methionine solution (1%) is then added, the mixture is shaken well and EDTA released from the Pd–EDTA complex is titrated against standard zinc sulfate solution. Reproducible and accurate results are obtained for 2.5–22 mg of Pd with relative errors <±0.6% and standard deviations <0.06 mg. The interferences of various ions were studied. The method was applied to the determination of palladium(II) in its alloy compositions.