A new procedure for the wet chemical analysis of the lead—noble metals button

Thiobarbituric acid can be used as a group precipitant for the recovery of Pt, Pd, Rh and Au from the lead perchlorate—perchloric acid solution, obtained after the lead—noble metals button has been parted with perchloric acid. By integration of this procedure with the recovery of Ir, Ru and Os from the parting residue, a scheme is evolved which makes possible the determination of all the platinum metals and gold from a single button. The results of analyses of various platiniferous materials by the proposed lead—wet method and the classical lead-cupellation method are compared.