SPECTROPHOTOMETRIC AND DERIVATIVE SPECTROPHOTOMETRIC DETERMINATION OFPALLADIUM(II) USING PYRIDOPYRIDAZINE DITHIONE IN THE PRESENCE OF NONIONIC SURFACTANT

Pyridopyridazine dithione (PPD) was synthesized as a new sensitive and selective reagent for spectrophotometric and derivative spectrophotom etric determination of palladium(II). In aqueous and micellar medium, PPD forms 1:4 complexes having molar absorptivities of 4.68 x 10(4) an d 5.74 x 10(4) l mol(-1) cm(-1) at 570 and 615 nm, respectively. Beer' s law was obeyed up to 2.2 and 2.5 mu g ml(-1) with detection limits o f 0.2 and 0.1 mu g ml(-1). The relative standard deviations for 1.23 m u g ml(-1) were 2.6 and 1.3%, in the absence and presence of Triton X- 100. In fourth-derivative mode, the regression equation, linear range, detection limit and RSD for 0.075 mu g ml(-1) were D-4 = 4.3C + 1.5 x 10(-3) 0.013 - 0.23 mu g ml(-1), 3.7 ng ml(-1) and 0.78%, respectivel y. The ionization constants of the reagent and stability constants of the complexes were evaluated. The method is free from interference by most common metal ions and anions. The method was applied for determin ation of palladium in activated charcoal.