BS ISO 685:2020,Analysis of soaps — Determination of total alkali content and total fatty matter content.BS ISO 685:2020 pdf free download.
BS ISO 685:2020 specifies a method for the simultaneous determination of the total alkali content and the total fatty matter content of soaps (including liquid soaps), excluding compounded products.
ISO 3819, Laboratory glassware- Beakers;
ISO 8212, Soaps and detergents – Techniques of sampling during manufacture.
Decomposition of the soap by a known volume of standard volumetric mineral acid solution, extraction separation of the liberated fatty matter with light petroleum and determination of the total alkali content by titration of the excess of acid contained in the aqueous phase with a standard volumetric sodium hydroxide solution. After evaporation of the light petroleum from the extract, dissolution of the residue in ethanol and neutralization of the fatty acids with a standard volumetric potassium hydroxide solution. Evaporation of the ethanol and weighing of the soap formed to determine the total fatty matter content.