A Safer Approach to Chromium Oxide Digestion


Abstract

Chromium Oxide (Cr2O3) catalysts play an important role in chemical manufacturing; however, it is difficult to oxidize Cr(III) to Cr(VI) in digestion and this presents itself with analytical challenges. Traditionally, this sample type was digested via hotplate with perchloric and sulfuric acids or by fusion. The use of perchloric acid poses safety issues as it is an extremely strong oxidizing agent that can cause an explosion in the presence of organics. Perchloric acid should be avoided if the chemist is unable to obtain the appropriate washdown hood and PPE requirements for its use. Chemists at CEM and Chemours have been working together to develop a digestion method to safely digest this sample type without resorting to perchloric acid, thus significantly improving the workplace safety for the analyst. In this study samples were prepared using a CEM MARS 6 microwave coupled with the iPrep vessel design allowing for total digestion using sulfuric and nitric acids.