Spectrophotometric determination of platinum with iodide and pyronine G

A sensitive and selective spectrophotometric procedure for the determination of platinum is described. The method is based on the interaction of Pyronine G with the hexaiodoplatinate(IV) anion to form a pink product that is stable for 24 h when stabilised with gelatin. Platinum concentrations as low as 0.02 p.p.m. can be readily determined. The method is precise and has been applied to the determination of platinum in synthetic alloys and mineral samples and palladium foil.