3. Special cases: refractory materials, volatile elements and ultratraces

3.1 General

The main difficulties encountered in dissolving materials such as the platinum group elements (PGEs) Ru, Rh, Pd, Ir, Pt and Os, whose concentrations are difficult to measure due to their low abundance and the nugget effect sometimes observed in rocks, are of several types:

• some refractory materials are very difficult to dissolve, since the temperature reached is not sufficient to allow them to oxidize;

• certain elements become volatile in the oxidized state, and the risk of losing them becomes significant by definition;

• the use of certain reagents leads to procedural blanks whose level is no longer compatible with the study of certain elements whose concentrations,...