SEPARATIONS OF MAJOR SOYBEAN PHOSPHOLIPIDS ON BETA-CYCLODEXTRIN-BONDED SILICA

The four major phospholipids (PL) phosphatidylcholine (PC), phosphatid ylethanolamine (PE), phosphatidylinositol (PI), phosphatidic acid (PA) found in soybean oil were separated by normal-phase high-performance liquid chromatography (HPLC) on beta-cyclodextrin-bonded silica (CDS) with UV detection. Adequate base-line separations of the PL components were achieved by isocratic elution with mobile phases containing hexa ne, isopropanol, ethanol and water/tetramethylammonium phosphate (TMAP ). The presence of TMAP in the mobile phases was critical to improve c omponent resolution and enhance peak symmetry. Analyte retention and c omponent separations were dramatically influenced by a small change in mobile phase compositions. Under the HPLC conditions employed, the el ution order appeared to follow Dhe order of increasing PL polarity wit h increasing retention times (PE < PC < PI < PA). The HPLC method was used in the qualitative analyses of selected commercial lecithin sampl es. Potential applicability of the HPLC-W-CDS technique for the quanti tative analysis of several crude oil samples derived from genetically modified soybean oil is demonstrated.