FATTY-ACID COMPOSITION OF GLYCEROPHOSPHOLIPIDS IN 7 TISSUES OF COD (GADUS-MORHUA), DETERMINED BY COMBINED HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY AND GAS-CHROMATOGRAPHY

A method for the separation from fish tissues of the four main glycerophospholipid classes, phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol and phosphatidylserine, using adsorption high-performance liquid chromatography with ultraviolet detection and consecutive gas chromatographic analysis, based on one injection for their fatty acid compositions, is described. Fatty acid 19:0 was used as an internal standard for the calculation of the relative concentrations of the phospholipids. The patterns of fatty acid distribution within each of the phospholipids from seven cod organs had some general similarities. Phosphatidylcholine had the highest levels of 16:0 and 18:2 n - 6, and the ratio of 20:5 to 22:6 varied between 0.5 and 0.9. Phosphatidylethanolamine had the highest total polyunsaturated fatty acids, (n - 3) polyunsaturated fatty acids, and 22:6 n - 3, and the ratio of 20:5 to 22:6 varied between 0.2 and 0.5. Phosphatidylinositol showed the highest level of 18:0 and 20:4 n - 6 and had the lowest ratio of (n - 3) to (n - 6). Phosphatidylserine had the highest ratio of (n - 3) to (n - 6) and the lowest ratio of 20:5 to 22:6, A generally low level (less than 1.5%) of the long-chain monoene, 22:1, was found in the phospholipids in all tissues.