Determination of palladium(II) with picramine-epsilon

We found a reaction of palladium(II) with picramine-epsilon to give a colored complex with an absorption maximum at 556 nm and a molar absorption coefficient of (2.01 ± 0.02) × 10⁴. Conditions of spectrophotometric reaction were selected for determining palladium(II) in nitric acid solutions or solutions containing aqua regia without the conversion of initial complexes into other forms. A rapid procedure was developed for the direct spectrophotometric determination of palladium(II) in concentrations down to 0.5 mg/L in various process solutions (including those containing nitric acid and aqua regia) within 15 min.