Anodic stripping tin titration: a method for the voltammetric determination of platinum at trace levels

We propose here a novel voltammetric method for the determination of platinum at trace levels. The method is based on the interference that platinum generates on the anodic stripping signal of tin acidic solutions: in appropriate conditions platinum uses the intermediate formation of tin(II) ions, taking place during the tin cathodic reduction, to reduce itself and to form mixed Pt(II)-Sn(II) chloro-complexes. From the analysis of the anodic stripping plots obtained after subsequent additions of tin in a Pt-containing solution, it is possible to quantify accurately and precisely the Pt concentration from 3 ppb to more than 10 ppm. This novel method is validated for the analysis of Pt in heterogeneous catalysts, but in principle could be extended to other matrixes.