Has anyone ever heard of a method of Gravimetric Analysis of Pt in an Aqua Regia solution? I have never heard of one. This "method" supposedly involves adding some super secret ingredient to the aqua regia to get it to drop out in a powder. My preferred method of analysis for this type of material would be to run it on an ICP, or an AAS (with a La adjunct), since it is already in an aqueous form. Any thoughts?