Identification and estimation of LAS in waters and effluents

The detergent industry of the United States has replaced alkylbenzene sulfonate (ABS) derived from tetrapropylene by linear alkylate sulfonate (LAS) in its formulations in an effort to eliminate waste surfactants from the nation's pollution load. The effectiveness of this move will be assessed by the monitoring of sewage treatment plant effluents and receiving waters by numerous agencies during the next several years. Most of the analytical methods available respond to a whole range of surfactants and are not specific for LAS. This deficiency can be avoided by use of the desulfonation-gas chromatography technique, which gives unequivocal proof of the presence or absence of LAS and is readily applicable at the range of interest in the neighborhood of one part per million. Examples are given of examination of various samples for presence and semiquantitative estimation of LAS. A simple procedure is described for prepurification and separation of anionic surfactants from other components of the sample. Presented at the AOCS Meeting, Cincinnati, October 1965.