DETERMINATION OF SURFACTANT SODIUM LAURYL ETHER SULFATE BY ION-PAIRING CHROMATOGRAPHY WITH SUPPRESSED CONDUCTIVITY DETECTION

A method for the determination of the anionic Steel CS-330 surfactant is described. CS-330 is a complex mixture of oligomers due to the Vari ous sizes of fatty alcohols and the number of moles of the ethoxylatio n. The main component of CS-330 is sodium lauryl ether sulfate (SLES). Since a SLES molecule has a hydrophilic sulfate head and a hydrophobi c alkyl ethoxyl tail, it is very difficult to separate these molecules with conventional reverse phase chromatography or ion exchange chroma tography. This work uses ion pairing chromatography with suppressed co nductivity detection. The separation of oligomers in CS-330 is achieve d. SLES does not have UV-absorbing chromophores, therefore an optical detector is not very sensitive. Suppressed conductivity detection tech nique significantly increases sensitivity and a quantitation limit of 56.60 ppm is achieved.