HPLC Analysis of Nonionic Sufactants. V. Ethoxylated Fatty Acids

Abstract

High performance liquid chromatography technique was used in order to achieve separation and identification of product composition of nonionic surfactants of ethoxylated fatty acids. Lichrosorb SI-60 (10μm) column, under gradient elution of mixture of isopropanol, methanol and n-hexane (50°C) and UV detector at 220 nm, were used for best separation of ethylene oxide (EO) adducts of fatty acids consisting of up to 20 EO units. No derivatization of the compounds was needed. An improved baseline, in spite of gradient elution, was achieved by adding negligible amounts of anthracene to the eluents. Brominated ethoxylated fatty acids resulting from addition of bromine to the double bond of the hydrophobic chain were also separated without a need for change in elution conditions or derivatization.