Spectrophotometric studies on the platinum(IV)-prochlorperazine bismethanesulfonate complex

We have studied the formation of a platinum complex and developed a simple, rapid and sensitive spectrophotometric method for the determination of platinum in solution. The method is based on the complexation reaction of the chromogen, prochlorperazine bismethane-sulfonate (PCPMS), with platinum(IV) in phosphoric acid medium which forms a reddish brown 1 1 complex with an absorption maximum around 528 nm. The reaction is fast in the presence of copper(II) and goes to completion within 1 min. Beer's law is obeyed over the concentration range 0.3–7.2 g/ml of platinum(IV) with an optimal range of 1.2–6.6 g/ml. The molar absorptivity is 2.65 × 10⁴1 mol^–1 cm^–1 and the Sandell's sensitivity is 7.8 ng cm^–2. The stability constant, logK, of the complex is 4.96±0.1 at 25 ° C. The effects of time, temperature, concentrations of acids, PCPMS and copper(II), and the interference by various ions are investigated. The method has been successfully applied to the determination of platinum content in alloys and minerals.