Hi, has anyone much expereince in parting fire assay prills which contain substantial amounts of ruthenium? I have had recent issues in determination of Au, Pt and Pd following a lead fire assay. The prill contains ruthenium which hinders the dissolution of the the prill with parting strength nitric acid. My typical ratio of Ag to precious metal is between 6 and 20 and even at the latter sometimes the silver does not dissolve fully resulting in cupelling again with more silver. Any advice would be much appreciated.