Polyurethane foams as sorbents for noble metals. Selective pre-concentration of small amounts of platinum from hydrochloric acid containing tin(II) chloride followed by flame atomic absorption analysis

Abstract

Small amounts of platinum may be selectively and quantitatively collected by means of polyether-type polyurethane foams from dilute (1.0–3.5 M) HCl in the presence of tin(II) chloride. The presence of Ni, Cu, Fe, Mn, Co, Zn, Ru, Ir and Rh and up to 0.1 M SO₄^2–, ClO₄^– and NO₃^– does not significantly interfere. Only Rh is co-extracted with Pt. The loaded foams are readily dissolved in HNO₃-HCl for analysis by flame atomic absorption spectrometry. Up to 95% of the sorbed platinum may be eluted from the foam using hot (70 °C) 5–10%V/V HCl in ethanol.