HPLC of platinum metals and gold based on their bromo complexes

Pt-II,Pt-IV, Pd-II, and Au-III can be separated and quantitated by HPLC in the form of ion-associates of their bromo complexes with the cetyltrimethylammonium (CTMA) cation, using the acetonitrile-water 60 : 40 system containing 0.002 mol l(-1) CTMA and 0.05 mol l(-1) NaBr (pH 3) as the mobile phase and detection at 240 nm. In such circumstances the detection limits for the injection of 20 mu l sample are 6.7, 0.4, 0.9, and 4.3 ng for Pt-II, Pt-IV, Pd-II, and Au-III, respectively. Excess Fe3+, Al3+, Mg2+, Ca2+, NO3-, SO42-, and Cl- does not interfere. On-Line preconcentration of the Pt-II,Pt-IV bromo complexes on Separon SGX RPS is recommended.