ISO 6490-1:1985 Preview
Animal feeding stuffs -- Determination of calcium content -- Part 1: Titrimetric method
This standard was last reviewed and confirmed in 2016. Therefore this version remains current.
The method is applicable to products having contents greater than 1 g/kg. It consists in ashing of a test portion, treatment of the ash with hydrochloric acid and precipitation of the calcium as calcium oxalate, dissolution of the precipitation in sulfuric acid and titration with standard volumetric potassium permanganate solution of the oxalic acid formed.