RAPID-DETERMINATION OF ANIONIC SURFACTANTS IN AN AQUEOUS-MEDIUM BY THE ION-ASSOCIATION TITRATION METHOD COUPLED WITH A STREAMING POTENTIAL DETECTOR

An ion-association titration method coupled with a streaming potential detector was developed for the determination of anionic surfactants i n a one-phase aqueous system. The titrant, benzethonium chloride (Hyam ine) ion, was added to an anionic surfactant solution. The potential t hen changed from negative to positive along with an increase in the ad ded titrant. The end point was read from an inflection point of a diff rential curve. The usual samples were titrated within 10 min. Anionic surfactants at concentrations from 10(-5) similar to 10(-3) mol dm(-3) could be determined by the proposed method. standard deviations of va rious anionic surfactants were 0.2 similar to 0.6%. method was applied to the determination of various anionic surfactants and anionic surfa ctants in commercial detergents. The results obtained for practical sa mples were in good agreement with those of the JIS titration method (E pton method).