Use of Transition Metal Forms in Separation of Lipid Components

Abstract

Fatty acids (FAs) play an important role in physiological functions. Hence, separation and isolation of FAs is of great industrial importance. Studies presented here were conducted with the intention of developing scalable and cheaper means of separating different forms of lipid constituents. In the first study, aqueous solutions of metallic salt(s) were brought in contact with mixtures of saturated (C16:0) and unsaturated (C16:1) fatty acid methyl esters (FAMEs). In the second study, select FA forms were used. The goal here was to investigate whether metal ions in their solvent state form strong enough complexes with either the saturated or unsaturated forms of FAMEs or FAs to selectively pull the ensembles out from a mixture. Results showed that although the FAME forms did not show a significant selectivity toward separation, saturated FA forms preferentially bound to select metal ions allowing separation of these from a mixture.

The third study involved elucidating the effect of Zn^(2+) concentration on the separation behavior of mixtures of saturated and unsaturated FAs (in methanol). Results showed that a concentration of 30 mg/ml of ZnSO_(4) could decrease the concentration of C16:0 FAs in the solution by 58%. IR spectra of the precipitate obtained in the second study supported the fact that the precipitate obtained is due to a complex between zinc ion and the carboxylate group of the C16:0 FA. Computational chemistry calculations indicate that the that specific complex formation with the saturated FA may be due to structural differences between C16:0 FA and C16:1 FA and their respective metal carboxylates.