High performance liquid chromatography of fatty acids as naphthacyl derivatives

A procedure for the separation of fatty acids, after their derivatization as fatty acid naphthacyl esters, by reverse-phase high performance liquid chromatography is described. A reproducible resolution (50 min), shorter than former HPLC analyses, of a standard mixture of fatty acid naphthacyl esters (25 fatty acids; C7:0 - C22:6 n - 3), was achieved by a ternary elution gradient of methanol-acetonitrile-water. Compared with gas chromatography, HPLC analysis of fatty acid naphthacyl esters showed similar percentages of molar distribution of long-chain fatty acids (≥14 carbons). The separation was monotered by UV absorbance at 246 nm, which was highly sensitive (the detection limit was about 0.1 ng), did not destroy the fatty acid naphthacyl esters and thus allowed individual recovery for further analysis (specific radioactivity determination or positional isomer identification). This preparative HPLC method provides, therefore, a useful process for the study of fatty acid metabolism in biological systems.