ISO 2753:1973

Urea for industrial use — Determination of water content — Karl Fischer method

Specifies the manner in which this method is to be applied in a reaction of any water present in urea with a solution of iodine and sulphur dioxide in a mixture of pyridine and methanol (Karl Fischer reagent). This reagent is first standadized by titration with a precisely known mass of water. The end point of the reaction is read by the direct visual or direct electrometric method. The method has also been approved by the IUPAC.