Solvent extraction and spectrophotometric determination of palladium(II) with 2,2′-bipyridyl 2-pyridylhydrazone (DPPH)

Abstract

The described spectrophotometric determination of palladium involves the extraction of the DPPH-Pd(II) complex from an acidic aqueous solution (0.5–1.5 N HCl) into a chloroform layer. The asorbance of the extracted solution is measured at 585 nm. The molar absorptivity of the complex is 1.9 × 10⁴ l mol^–1 cm^–1 at 585 nm. The effects of pH (2–12), HCl concentration, DPPH concentration and shaking time were studied. The ratio of ligand molecules to metal ions in the coloured complex was found to be 1 : 1. Tolerance amounts for many metals have been determined. Finally, a procedure for the determination of palladium in dental alloys is recommended. The determination is selective, sensitive and accurate.