Résumé
Principle: Aqueous extraction of a test portion, followed by the evaporation and drying at 102 +/-2 degrees centigrade, and sulfating and ashing of the residue at 800 degrees centigrade, to yield the water-soluble inorganic matter. Treatment of the residue with hydrochloric acid, and titration with standard volumetric disodium ethylenedinitrilotetraacetate solution.