KNO3的纯度检测根据usp的方法检测但是发现结果滴定不出来，即根本没有KNO3 。如下为USP方法：Assay— [note—Use water that is carbon dioxide- and ammonia-free.]Cation-exchange column— Transfer strongly acidic styrene-divinylbenzene cation-exchange resin (16- to 50-mesh) to a 2-cm diameter chromatographic column to a depth of about 20 cm.Procedure— Dissolve about 400 mg of Potassium Nitrate, accurately weighed, in 100 mL of water. Pass this solution through the Cation-exchange column at a rate of a.

检漏时，我查的好多都写GC气路的检漏用1：1的异丙[wiki]醇[/wiki]/水我想问下，很多场合都用异丙醇，都不用正丙醇，为什么呢？正丙醇和异丙醇有什么区别？实验室里没有异丙醇，检漏能否用正丙醇代替呢？