ISO 3122:1976

Boric acid, boric oxide, disodium tetraborates, sodium perborates and crude borates for industrial use — Determination of iron content — 2,2'- Bipyridyl photometric method ISO 3122:1976

Publication date:   Apr 1, 1976

Scope

Preliminary reduction of the iron(III) by hydroxylammonium chloride, if required, suppression of the interference of tin by oxalic acid. Formation of the coloured iron(III)-2,2'-dipyridyl complex in a buffered medium. Photometric measurement of the coloured complex at a wavelength of about 522 nm.