Determination of noble metals in ores containing copper, iron and nickel by graphite furnace AAS after tellurium coprecipitation/ion exchange separation

Abstract

A sample was decomposed with aqua regia in a Teflon sealed vessel at 180°C for 5 h. Interferences by coexisting elements were significant in electrothermal AAS. Therefore, coprecipitation method with tellurium was used for separation of Au, Pt, Pd and Rh from the matrices. Small amounts of coexisting elements coprecipitated with tellurium were further eliminated by cation exchange separation. Silver was separated only by the cation exchange separation because of the poor recovery by tellurium coprecipitation. This method was applied to the Canadian certified reference materials, PTC and PTM, and analytical results were in good agreement with the certified values (R.S.D.: 35%).