Simple method for spectrophotometric determination of cationic surfactants without liquid–liquid extraction Original Research Article

A simple method for the spectrophotometric determination of cationic surfactants was studied. The ion associate of tetradecyl-dimethylbenzylammonium chloride (Zephiramine) and tetrabromophenolphthalein ethyl ester (TBPE) were adsorbed onto the walls of a PTFE vessel by vigorous shaking. After discarding the resulting solution, the ion associate was dissolved in methyl cellosolve and its absorbance was measured at 605 nm. The molar absorptivity for Zephiramine was 7.88×104 l mol−1 cm−1.