该方法基于以下事实:非离子加合物和聚乙二醇均溶于氯化钠溶液，但其中一种溶于乙酸乙酯，而另一种则不溶于。因此，可以通过以下方法分离聚乙二醇和加合物:将样品溶解在乙酸乙酯中，并用氯化钠溶液萃取聚乙二醇。用氯仿萃取氯化钠溶液中分离的聚乙二醇，去除溶剂并称量残留物。 蒸发含有加合物的乙酸乙酯溶液并称量残留物。

The method relies on the facts that both non-ionic adducts and polyethylene glycols are soluble in sodium chloride solution, but one is soluble in ethyl acetate whereas the other is not. Separation of the polyethylene glycols and the adducts is, therefore, possible by the following methods: Dissolution of the sample in ethyl acetate and extraction of polyethylene glycols by sodium chloride solution. Extraction of the polyethylene glycols isolated in the sodium chloride solution with chloroform, removal of the solvent and weighing of the residue. Evaporation of the ethyl acetate solution which contains the adducts and weighing of the residue.