Highly Selective Procedure for Trace Analysis of Platinum(IV) in Its Allied Materials

Abstract

4-Phenylthiosemicarbazide (HPTS) was investigated as a new collector for the flotation of platinum(IV). The metal ion forms a (1:2) pale green complex with HPTS in the aqueous solution. An intense clear green layer was formed, after flotation, by adding oleic acid (HOL) surfactant. The composition of the float is 1:2 (Pt:HPTS). A highly selective and sensitive spectrophotometric procedure was proposed for the determination of microamounts of Pt(IV) as its floated complex. The flotation-determination method was achieved in the pH range 3-7. Beer′s law was obeyed up to 6× 10^-5mol l^-1(11.7ppm). The interferences from various foreign ions were avoided by adding excess HPTS. The molar absorptivities of Pt-HPTS and Pt-HPTS-HOL systems are 2×10³ and 4.7×10³l mol-1 cm-1 at 660 and 690nm, respectively. The formation constants of the species formed in the presence and absence of HOL are calculated. The method was successfully applied to the determination of Pt(IV) in its allied materials. A mechanism of flotation is suggested.