Abstract
A method for the separation and determination of the components of a sulfonate type anionic surfactant mixture including 2-sulfonatofatty acid methyl ester (α-SF) was developed. It is quite difficult to isolate linear alkylbenzenesulfonate (LAS), α-olefin sulfonate (AOS), alkane sulfonate (SAS) and α-SF from mixture of these compounds. However, when converted to their sulfonic acid methyl ester derivatives, separation is possible by high performance liquid chromatography (HPLC). The methyl sulfonate mixture was separated into α-SF, AOS, and (LAS and SAS) by normal phase HPLC, and the content of each was determined from the peak area. The eluents were collected into flasks and subject to reversed phase HPLC analysis of alkyl homologue distribution. The ratio of LAS to SAS was determined by means of NMR spectroscopy. Mixtures of α-SF, LAS, AOS, and SAS with definite composition were analyzed by this method. The results for alkyl homologue distribution agreed well with those for raw materials of fatty acid such as methyl ester, linear alkylbenzene, α-olefin or n-paraffin.
