Efficient determination of average valence of manganese in manganese oxides by reaction headspace gas chromatography

•Efficient quantification of average valence of manganese (Mn) in Mn oxides.•This method is based on the oxidation reaction between Mn oxides and sodium oxalate under the acidic condition.•The CO2 generated from the reaction can be quantitatively analyzed by headspace gas chromatography.•The present method is suitable for the quantification of Mn average valence in Mn oxide related products.

This work investigates a new reaction headspace gas chromatographic (HS-GC) technique for efficient quantifying average valence of manganese (Mn) in manganese oxides. This method is on the basis of the oxidation reaction between manganese oxides and sodium oxalate under the acidic condition. The carbon dioxide (CO2) formed from the oxidation reaction can be quantitatively analyzed by headspace gas chromatography. The data showed that the reaction in the closed headspace vial can be completed in 20 min at 80 °C. The relative standard deviation of this reaction HS-GC method in the precision testing was within 1.08%, the relative differences between the new method and the reference method (titration method) were no more than 5.71%. The new HS-GC method is automated, efficient, and can be a reliable tool for the quantitative analysis of average valence of manganese in the manganese oxide related research and applications.