One-step simple method for the determination of palladium using 3-acetyl2-thiohydantoin as a releasing agent

Abstract

A simple, rapid and accurate complexometric method for the determination of palladium(II) is proposed, based on the selective masking property of 3-acetyl-2-thiohydantoin (ATH) towards palladium(II). In the presence of diverse metal ions, palladium(II) is complexed with excess of EDTA and the surplus EDTA is back titrated with standard lead nitrate solution at pH 5-6 (acetic acid - sodium acetate buffer) using xylenol orange as indicator. An excess of a 0.5% solution of ATH is then added to displace EDTA from Pd(II) - EDTA complex. The released EDTA is titrated with the same standard lead nitrate solution as before. Reproducible and accurate results are obtained in the concentration range 0.35-11.00 mg of palladium with relative error of ±0.46% and coefficient of variation not exceeding 0.36%. The effects of diverse ions are studied. The method is used for the determination of palladium in alloys, hydrogenation catalyst and complexes with a fair degree of accuracy.