ISO 731-6:1977

Formic acid for industrial use — Methods of test — Part 6: Determination of iron content — 2,2'- Bipyridyl photometric method ISO 731-6:1977

Publication date:   Mar 1, 1977

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.