m-Benzene disulfonic acid (BDS) as a superior accompanying acid for routine silicate rock analysis

We recommend that m-benzene disulfonic acid (BDS) be used with hydrofluoric acid during the dissolution of silicate rocks and minerals for purposes of routine analysis of RO and R₂O groups and trace elements. This recommendation is based on several properties that make it superior to the alternative acids. These properties include: (1) a relatively high boiling point (resulting in more effective removal of HF and silica); (2) the high solubility of virtually all salts of BDS; (3) the non-complexing characteristics of BDS salts; (4) the thermal stability of BDS (resulting in very slight degassing at elevated temperatures, thus reducing splattering); and (5) the safety of BDS compared with highly oxidizing acids such as perchloric.