Determination of anionic surfactants by two‐phase titration with tetrabromophenolphthalein ethyl ester as indicator

Abstract

Abstract A method has been developed for the determination of anionic surfactants in aqueous solution. It is based on solvent extraction titration of an ion pair. Zephirmine (tetradecyldimethyl ammonium chloride) is used as a titrant with tetrabromophenolphthalein ethyl ester as an indicator in the presence of chloroform. In the two‐phase titration (chloroform/water), the proposed procedure gives sharp end‐points as the organic phase changes from yellow to blue. The aqueous phase is colorless throughout the titration.