Determination of Cationic Surfactants with Congo Red by Spectrophotometry

A spectrophotometric method is developed for the determination of cationic surfactants based on the formation of ion-aassociate compands of Congo red with cationic surfactants in aqueous solution.The maximum absorption exhibits at 465nm.the colour reaction conditions for CR-CS system isstudied.The result indicates that the colour reaction can be applied to direct spectrophotometric determination of cationic surfactants in aqueous solution.