o-Hydroxyacetophenone thiosemicarbazone as a reagent for the rapid spectrophotometric determination of palladium.

o-Hydroxyacetophenone thiosemicarbazone has been synthesized and employed as a new reagent for the spectrophotometric determination of palladium(II), which forms two complex species with it in aqueous dimethylformamide at pH 6.0, these having 1:1 and 1:2 metal-ligand ratios. The Job and molar-ratio plots have an unusual shape that is due to the stepwise conversion of the 1:1 complex into the 1:2 species. The molar absorptivity at 370 nm is 9 x 10(3) l.mole(-1).cm(-1). Beer's law is obeyed over the range 0.42-10.6 mug/ml palladium.