Simultaneous determination of iron(II) and iron(III) oxides in geological materials by ion chromatography

Abstract

The determination of iron species in geological materials is important for the geochemical study of the Earth and for petrology. The simultaneous determination of iron(II) and iron(III) oxides in geological materials by means of ion chromatography, with the use of a post-column method, has been investigated. Optimum analytical conditions were achieved and the interference from co-existing ions of copper, nickel, zinc and manganese was evaluated to be less than 3% for Fe³⁺ and less than 2% for Fe²⁺. Geological reference rocks were analysed by the proposed method, and the results were in good agreement with other data. The reproducibility is 3.3% for Fe₂O₃ and 1.4% for FeO. The method was also applied to the analysis of sedimentary rocks that contained large amounts of organic carbon.