Selective Flotation-Spectrophotometric Procedure for the Trace Analysis of Palladium(II) in Different Matrices

摘要

2-Hydroxyimino-3-(2-hydrazonopyridyl)-butane (HHB) was investigated as a new reagent for the flotation of palladium(II). The metal ion forms a 1:1 pale-violet complex with HHB in aqueous solution. An intense clear violet layer was formed, after flotation, by adding an oleic acid (HOL) surfactant. The composition of the float is 1:1 (Pd:HHB). A highly selective and sensitive spectrophotometric procedure was proposed for the determination of microamounts of Pd(II) as its floated complex. The flotation-determination method was achieved in the pH range 2.5 - 7.0. Beer’s law was obeyed up to 6×10-5 mol l-1 (6.3 ppm). Interference from various foreign ions was avoided by adding excess HHB. The molar absorptivities of Pd-HHB and Pd-HHB-HOL systems are 2.5×103 and 2.1×104 l mol-1 cm-1 at 555 nm, each. The formation constants of the species formed in the presence and absence of HOL are 9×105 and 4.6×107 l mol-1, respectively. The method was successfully applied to the analysis of Pd(II) in simulated ores, complexes, and water samples. The separation mechanism is discussed.