You are right about the loss of Os as due to formation of volatile OsO4. Ascorbic acid or cysteine added to a digestion vessel with nitric acid will only get the ascorbic acid and cysteine digested as well.
I agree with what Robert Thomas said about checking the Inorganic Ventures web site regarding the use of alkaline nitrate fusion without HCl or KCl to prepare samples for Os or Ru analysis. However, in the Inorganic Ventures discussion, APDC (Ammonium pyrrolidinedithiocarbamate) is suggested. One must be aware that the longer APDC is in strong base, and the higher the temperature, the more APDC is decomposed as well, so experience plays a strong part in successful analysis.
Tiene razón que la pérdida de Os está debido a la formación de OSO4 volátiles. La adición de ácido ascórbico o de cisteína a un vessel de la digestión por ácido nítrico resultirá solamente en el ácido ascórbico y la cisteína también digerido.
R. Steven Pappas, Ph.D.
Team Lead, Tobacco Inorganics Group
Centers for Disease Control & Prevention
4770 Buford Highway, NE
M.S. F44, Building 110
Atlanta, GA 30341-3717, USA
From: PLASMACHEM-L: Analytical Chem.(ICP's, DCP's, MIP's). <[log in to unmask]> On Behalf Of Paqui Polonio
Sent: Monday, May 14, 2018 9:52 AM
To: [log in to unmask]
Subject: Osmium stability analyses
We are analyzing some samples of pharmaceutical industry. We are having bad recoveries in the analysis of osmium. After searching the possible problem, we have reach the conclusion that when we digest the sample the osmium reacts in the oxidizing media giving OsO4(g). In the literature are given some possible solutions to this problem. Stabilizing the osmium with a solution of ascorbic acid or cysteine.
Does anyone use this to stabilize osmium? Wich concentration of ascorbic acir or cysteine should we use?
Do you know any other possible solution to this problem?
Thank you in advance.