Spectrophotometric determination of palladium by reaction with tin(II) in binary halide mixtures

The coloured complexes produced in the systems Pd(II): Sn(II):X:X', where X and X' are different halide ions, have been studied. In bromide/iodide mixtures, palladium(II) reacts with tin(II) species in acidic ethanol media to form a deep purple complex with maximum absorption at 555 nm. This is the basis of a rapid and sensitive spectrophotometric method for the determination of palladium. The complex is stable in the absence of air, but water interferes and must not be present in amounts more than 15% of the total volume of the ethanolic mixture.