Separation and identification of triglycerides, cholesteryl esters, cholesterol, 7-dehydrocholesterol, dolichol,...

A simple isocratic high performance liquid chromatography (HPLC) system is described that allows separation and identification of cholesteryl esters, triglycerides, ubiquinone, alpha-tocopherol, dolichol, cholesterol, 7-dehydrocholesterol, and retinol. This consisted of a normal phase cyanopropyl column with 0.1% isopropanol in heptane as the solvent. The effluent was monitored with an LKB model 2140 diode array detector which enabled the lipids to be identified by their characteristic absorption spectra. This system was applied to a sample of dog liver in which cholesteryl esters, retinyl esters, triglycerides, ubiquinone, dolichol, cholesterol, and retinol were identified. Retinyl esters and vitamin D esters were identified by their similarity in absorption spectra to retinol and vitamin D. A system to transfer and store the chromatograms on the VAX PDP-11 or an optical disc is also described.