Abstract / scope
Conversion of the iron in a test portion to iron(III) sulphate by evaporation to dryness in the presence of sulphuric acid. Dissolution in nitrid acid, reduction of the trivalent iron in the solution thus obtained by hydroxylammonium chloride. Photometric measurement of the coloured complex iron(II)-2,2' -dipyridyl. Applicable to products having Fe contents in the range 0,1 to 2 mg/kg.