High pressure liquid chromatography of alpha olefin sulfonates

Alpha olefin sulfonates (AOS) are a complex mixture of the posi-tional isomers of hydroxyalkane sulfonates, alkene sulfonates, and disulfonates. This paper describes a qualitative method for separat-ing these various components by reverse-phase high pressure liquid chromatography. The column utilized was a DuPont Zorbax TMS (4.6 mm × 25 cm) with a water/methanol (25:75, v/v) mobile phase containing sodium nitrate at a concentration of 0.4M. The hydroxyalkane sulfonate and alkene sulfonate peaks were identified using laboratory prepared standards. The disulfonate peaks were located using controlled sulfonation conditions. More work needs to be done to separate an overlap of C₁₆ 3-hydroxyalkane sulfonate and C₁₄ 2-alkene sulfonate in 1416 AOS. However, if studies are based on single carbon number AOS samples, the overlap of these peaks can be avoided. This method can be utilized as a qualitative tool for the comparison of sulfonation runs, the identification of AOS within a detergent, or the identfication of the olefin type used for sulfonation.