INDIRECT COMPLEXOMETRIC DETERMINATION OF PALLADIUM(II) USING SODIUM-NITRITE AS A SELECTIVE MASKING REAGENT

A selective complexometric method is described for the determination o f palladium, sodium nitrite being used as masking reagent. Palladium(I I) in a given sample solution is initially complexed with an excess of EDTA and the surplus EDTA is titrated with zinc sulfate solution at p H 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 2.5-2 7.5 mg of Pd with relative errors less than or equal to 0.5% and stand ard deviations less than or equal to 0.05 mg. The interferences of var ious ions are studied. The method is applied for the determination of palladium(II) in alloys and complexes.