A gradient elution HPLC system was devised for the separation and quantification of natural lipids containing cholesterol ester (Ch-E), triglyceride (TG), free fatty acid (FA) and phospholipid (PL) as the major lipid constituents.
Standard lipid mixtures were chromatographed into individual classes varying in polarity on a silica column with UV detector (210 nm) by gradient elution using hexane : 2-propanol (100 : 0.15) and methanol : 2-propanol : 85% phosphoric acid (100 : 150 : 2.5) as the mobile phases.
Sample sizes of 1050μg fig for neutral lipids (Ch-E, TG and FA) and 200600 μg for polar lipid (PL) were optimum for quantification, and analysis was completed in 40 min.
Lipids extracted from human serum (ca. 0.1 mL) could be separated and accurately quantified by the HPLC system under the same conditions, as could also the standard mixture. Lipid compositions of serum lipids as determined by the present HPLC method agreed with those of enzymic methods used in clinical routine.