Analysis of sulfur compounds in acid sulfate soils and other recent marine soils

Abstract

Abstract A refined scheme for the semi micro chemical analysis of sulfur fractions in soils is presented. Pyrite is analyzed, as iron, after extraction in HNO3. Non‐pyrite iron is excluded by a pretreatment with HF/H2SO4. Water‐soluble sulfate and jarosite [KFe3(SO4)2(OH)6], the other dominant sulfur fractions in acid sulfate soils, are analyzed turbidimetrically, as sulfate, after successive extractions by EDTA.3Na (water soluble plus exchangeable SO4) and by hot 4 M HCl (jarosite). These methods are simpler, less bulky and more specific than most existing procedures. Introduction of elemental sulfur analysis permits estimation of organic sulfur fraction as well. Sums of individual sulfur fractions agree well with separate total sulfur determinations. The proposed analysis of pyrite permits also distinction of the components Fe2O3, FeO and FeS2 in soils and rocks2.