ISO 6122:1978

A test portion is dispersed in a sodium sulphate solution, and mixture of butan-l-ol and acetons is added to precipitate sodium sulphate decahydrate and part of sodium chloride. A mixture of alkane sulphonates (mono + di), which may be contiminated by a little sodium chloride is obtained by filtration. The solvent is evaporated so that the small quantities of paraffins are eliminated. The alkane sulphonates content is determined gravimetrically and any sodium chloride present is determined potentiometrically.