A novel electrooxidation vapor generation technique for the direct analysis of trace Os in ore/water samples

All electrolytic vapor generation technologies are based on cathodic reduction, but this paper focuses on how to use anodic oxidation to realize the gaseous transformation of noble metal Os. Supported by RuO2-based dimensionally stable anode (DSA), we found that the conversion from trivalent/tetravalent Os to the OsO4 can be carried out continuously and stably, even at the mu g L-1 level. Interestingly, there was a negative correlation between the conversion of OsO4 and the RuO2 content in the DSA. The decrease of oxygen absorption potential and the increase of current density suggest that the oxidation process of Os belongs to electrocatalytic behavior. The catalytic activity of the material has an obvious influence on the conversion of osmium while the formation of free radical may be crucial for the effective oxidation. Under the optimum conditions, this electrocatalytic synthesis of OsO4 combined with ICP-MS can realize the same effect of oxidation and detection of two osmium species [Os(III) and Os(IV)]. The proposed method exhibits a low limit of detection (5 pg kg- 1), a wide linear range (0.1-100 mu g L-1) and excellent anti-interference performance, which promotes the direct analysis of total Os in real ore samples without separation. Considering the catalytic activity of OsO4 in specific reactions, this green anodic electrosynthesis technology is also expected to provide more possibilities.

Automated summary

This paper focuses on the use of anodic oxidation to achieve the gaseous transformation of noble metal Os. The conversion of Os to OsO4 can be carried out continuously and stably using RuO2-based dimensionally stable anode (DSA). The catalytic activity of the material has a significant impact on the conversion of osmium, and the formation of free radicals may be crucial for effective oxidation. The electrocatalytic synthesis of OsO4 combined with ICP-MS enables the oxidation and detection of Os(III) and Os(IV) species, with low detection limit, wide linear range, and excellent anti-interference performance.