Sodium hydrogen carbonate for industrial use — Determination of iron content — 1,10- Phenanthroline photometric method

The method is applicable to products having a content equal to or greater than 0,1 mg/kg. The principle concists in reduction of the iron(III) by hydroxylammoniumchloride. Formation of a iron(II)-1,10-phennanthroline complex in a buffered solution. Photometric measurement of the coloured complex at a wavelength of about 510 nm.