Spectrophotometric determination of palladium after solid-liquid extraction with 1-(2-pyridylazo)-2-naphthol at 90 degrees C

An effective spectrophotometric determination of palladium with 1-(2-pyridylazo)-2-naphthol (PAN) using molten naphthalene as a diluent has been studied. A green complex of palladium with PAN is formed at 90 degrees C. In the range of pH 1.5-7.5, the complex is quantitatively extracted into molten naphthalene. The organic phase is anhydrously dissolved in CHCl3 to be determined spectrophotometrically at 678 nm against the reagent blank. Beer's law is obeyed over the concentration range of 0.5-10 ppm. The molar absorptivity and Sandell's sensitivity are 1.2 x 10(4) 1 mol(-1) cm(-1) and 0.0070 mg cm(-2), respectively. The optimum conditions for determination are obtained. The interferences of various ions are observed in detail. The method has been applied to the determination of palladium in synthetic samples. (C) 1997 Published by Elsevier Science B.V.