Enantioselective high-performance liquid chromatography analysis of oxygenated polyunsaturated fatty acids

Oxygenated polyunsaturated fatty acids (PUFAs)play an outstanding role in the physiological and pathological regulation of several biological processes. These oxygenated metabolites can be produced both enzimatically, yielding almost pure enantiomers, and non-enzymatically. The free radical-mediated non-enzymatic oxidation commonly produces racemic mixtures which are used as biomarkers of oxidative stress and tissue damage. The biological activity of oxygenated PUFAs is often associated with only one enantiomer, making it necessary of availing of lipidomics platforms allowing to disclose the role of single enantiomers in health and disease. Polysaccharide-based chiral stationary phases (CSPs) play a dominating part in this setting. As for the cellulose backbone, 4-methylbenzoate derivatives exhibit very high chiral recognition ability towards this class of compounds. Concerning the phenylcarbamate derivatives of cellulose and amylose, the tris(3,5-dimethylphenylcarbamate) variants show the best enantioresolving ability for a variety of oxygenated PUFAs. Moreover, also the amylose tris(5-chloro-2-methylphenylcarbamate)-based selector produces relevant chromatographic performances. The extreme versatility of those CSPs mostly depends on their compatibility with the most relevant elution modes: normal- and reversed-phase, as well as polar organic/ionic-mode. In this review article, a selection of enantioseparation studies of different oxygenated PUFAs is reported, with both tris(benzoates) and tris(phenylcarbamates) of cellulose and amylose.