Rapid characterization of fatty alcohol ethoxylates by non‐aqueous capillary electrophoresis

Abstract

Fatty alcohol ethoxylates (FAE) (a mixture of nonionic surfactants) have been characterized using NACE with UV detection. Phenyl polyurethane derivatives of these compounds were previously obtained by reaction with phenyl isocyanate. The derivatization reaction only requires microwave irradiation for 30 s (600 W). Phenyl polyurethanes were separated and characterized using a BGE containing a mixture of ammonium nitrate (15 mM), acetic acid (1.5%) and 9:1 v/v methanol/ACN. After optimization of the instrumental conditions for the separation, phenyl polyurethane compounds (formed from the corresponding FAE) with ethylene oxide numbers (EON) of 6 (certified standard and industrial samples), 7 and 10 (both as industrial samples), and 5.5 (microemulsion phase) were successfully separated and characterized. The properties of these FAE nonionic surfactants are very important in the petroleum industry, which requires characterization of the quality of the purchased materials as well as the final products in the microemulsion-oil-water stream process. This analytical objective has been achieved by the proposed NACE methods, allowing FAE to be distinguished from 5.5 to 10 EON with errors below 4%, and shows advantages against to HPLC methods.

Capillary Electrophoresis

“…Fatty alcohol ethoxylates (FAE) are a category of nonionic surfactants that are important in a microemulsion oil−water stream process in the petroleum industry. Arias et al report a new separation strategy using NACE to successfully separate FAE with ethylene oxide numbers ranging from 5.5 to 10 . FAE were derivatized with phenyl isocyanate to be detected with UV−vis.…”

Determination of Dodecanol and Short‐Chained Ethoxylated Dodecanols by LC–MS/MS (with Electrospray Ionization) After Their Derivatization (with Phenyl Isocyanate)

“…Separation of ethoxylated surfactants has been performed using capillary Electronic supplementary material The online version of this article (doi:10.1007/s11743-017-2015-z) contains supplementary material, which is available to authorized users. gel electrophoresis (CGE), capillary zone electrophoresis (CZE) [12,13], micellar electrokinetic chromatography (MEKC) [1], non-aqueous capillary electrophoresis (NACE) [14] and capillary electrochromatography (CEC) [1].…”

Analytical characterization of PEG polymers by MEKC

“…The oligomers have identical charge, but increasing mass. For this reason, the separations can be achieved according to the molecular size because the charge‐to‐mass ratio dominates the separation 25. CGE and CZE have been used for the oligomeric separation of PEGs with molecular mass of up to 5000 16, 26.…”