Development of a Reliable Method for the Spectrophotometric Determination of Palladium(II) with o-Methoxyphenyl Thiourea: Separation of Palladium from Associated Metal Ions

A simple and sensitive method is described for the solvent extraction and spectrophotometric  determination of palladium(II) using low concentrations of o-methoxyphenyl thiourea (OMePT). Trace concentrations of palladium(II) were quantitatively extracted when equilibrated withOMePTin chloroformat 1.0 mol  L–1hydrochloric acid media for 10 s. The absorbance of a yellow coloured palladium(II)-OMePT complex was measured at 325 nm. The palladium(II)-OMePT complex was stable for more than 72 h. The composition of extracting species was 1:1, determined by mole ratio, Job’s continuous variation method and it was confirmed by a log–log plot. Beer’s law was obeyed up to 15.0 μg mL –1 . The molar absorptivity and Sandell’s sensitivity were 3.38 × 103 L mol –1 cm –1 and 0.031 μg cm –2 , respectively. The method was free from a large number of interferences from cations and anions. The method was applied for separation of palladium(II) from multi-component mixtures and synthetic mixtures corresponding to alloy. KEYWORDS : Solvent extraction, spectrophotometric determination, o-methoxyphenyl thiourea, palladium.