Spectrophotometric determination of palladium after extraction with 3-hydroxy-2-methyl-1,4-naphthoquinone 4-oxime into molten naphthalene

Abstract

A sensitive spectrophotometric method has been developed for the determination of palladium after extraction of its 3-hydroxy-2-methyl-1,4-naphthoquinone 4-oxime (HMNQO) complex into molten naphthalene. The optimum pH range for the extraction is 4.0–6.0. The solid naphthalene containing the palladium-HMNQO complex is separated by filtration and dissolved in N,N-dimethylformamide. The absorbance is measured at 485 nm against a reagent blank. Beer's law is obeyed in the concentration range 0.41–6.78 p.p.m. of palladium. The molar absorptivity and Sandell sensitivity are 1.86 × 10⁴ l mol^–1 cm^–1 and 0.0056 µg cm^–2, respectively. The interference of various ions has been studied in detail and conditions have been established for the determination of palladium in synthetic samples, alloys and catalysts.