Submitted to: Journal of Chromatography
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/25/1996
Publication Date: N/A
Interpretive Summary: Phospholipids are important natural products found ubiquitously in cell membranes. Distributions of these substances in plants differ among varieties of the oilseeds. Methods are needed to identify components of phospholipids in vegetable oils. Comparative analytical evaluation of various oil samples is required to assess the impact of oilseed varietal differences on the lipid compositions. Analytical methods have been developed for the measurement of derivatives of phosphatidic acid and phosphatidylethanolamine in oil samples. Components in the lipid mixtures were separated by liquid chromatography and determined by spectrophotometric detection. The lipid components were isolated and the fatty acids were characterized by gas chromatography. Individual lipid species were also identified by chromatographic peak matching. The methods can be used in the analysis of complex lipid mixtures in plant oils. The analytical data provide useful information on differences in phospholipid levels affected by genetic modification of oilseeds.
Technical Abstract: Subcomponents of phospholipid (PL) derivatives in two structural series phosphatidic acid (PA) and phosphatidylethanolamine (PE) were separated on octadecylsilica by reversed-phase high-performance liquid chromatography (HPLC)-UV detection. Using a mobile phase of acetonitrile-methanol-water- quaternary ammonium phosphate (QAP), the individual PLs derived from egg PC Cwere resolved into six major subcomponents. The QAP electrolytes served a ion-pair counter-ions or ion-interactants depending on PL structures and on the QAP concentrations. Correlation of logarithmic capacity factors (k') of anionic PLs with the number of carbon atoms in QAP established linear relationships. The Ln k's of compounds in PA- and PE-series containing respective O-H and N-H functionalities were not linearly proportional to the number of carbon atoms in their corresponding O-alkyls and N-methyls. The k' values of negatively-charged PLs increased with increasing QAP concentrations. Conversely, inverse relationships between the QAP concen- trations and k' values of PE-derivative were observed in HPLC with low QAP concentrations. Structural modifications at PL head groups were advantageous for trace PL analyses.