ISO 2479:1972

Insoluble substances shall be defined by the conditions described in this document. The object is not to dissolve all the impurities but only those of interest to users. The method is applicable to the analysis, carried out inaqueous medium or in acid medium. The principle consists in solution of the test portion in water, filtration, drying and weighing of the insoluble residue. Dilution of the filtrate to form the main solution for carrying out other determinations.