Indirect complexometric determination of palladium(II) using sodium nitrite as a selective masking reagent

A selective complexometric method is described for the determination of palladium, sodium nitrite being used as masking reagent. Palladium(II) in a given sample solution is initially cornplexed with an excess of EDTA and the surplus EDTA is titrated with zinc sulfate solution at pH 4.5–5.5 (acetic acid-sodium acetate buffer), using xylenol orange as indicator. An excess of sodium nitrite is then added, the mixture is shaken well and the EDTA released from the Pd-EDTA complex is titrated with a standard zinc sulfate solution. Results are obtained for 2.5–27.5 mg of Pd with relative errors 0.5% and standard deviations 0.05 mg. The interferences of various ions are studied. The method is applied for the determination of palladium(II) in alloys and complexes.