在乙二醇存在下蒸发试样，并通过卡尔·费歇尔法和直接电测法测定残留物的含水量。该方法适用于含水量等于或大于50 mg/kg的产品。对于水含量大于1000 mg/kg的情况，最好根据ISO 4276用无水甲醇稀释蒸发残渣，并滴定稀释溶液的等分部分。

A test portion is evaporated in the presence of ethanediol and the water content of the residue is determined by the Karl Fischer method with direct electrometric measurement. The method is applicable to products having water contents equal to or greater than 50 mg/kg. For water contents greater than 1000 mg/kg it is preferable to dilute the evaporation residue with anhydrous methanol in accordance with ISO 4276 and titrate an aliquot portion of the diluted solution.