The effect of organic matter on the determination of iron(II) in soils and rocks

Abstract

In the determination of iron(II) in silicates, iron(III) is reduced by organic matter when the sample is dissolved in hydrofluoric acid.

Acidic reagents, such as aqueous aluminium chloride solution, that have been proposed for extracting labile iron(II) from waterlogged soils, suffer from the additional defect of causing partial dissolution of iron(II) sulphide, with the consequent risk that yet more iron(III) may be reduced by the liberated hydrogen sulphide.