Method for isolation of non-esterified fatty acids and several other classes of plasma lipids by column chromatography on silica gel.

A method is described for isolation from human plasma of non-esterified fatty acids, cholesteryl esters, triglycerides, cholesterol and diglycerides, monoglycerides, and some phospholipids by extraction and silica gel column chromatography. All of these lipid classes except diglycerides and cholesterol were separated cleanly in seven elution steps. Diglycerides and cholesterol were isolated together. Recovery of model compounds which represent the most significant classes of plasma lipids during the column chromatographic step was nearly complete. The overall recovery of added heptadecanoic acid from plasma specimens was 81% after both sample isolation steps. The overall recovery of added synthetic pentadecanoic acid and heptadecanoic acid ester lipid homologues from plasma was 80-91% after both sample preparation steps. About 6 h are required for extraction and isolation in duplicate of these lipid classes from twenty plasma specimens. Alternatively, non-esterified fatty acids can be isolated from twenty plasma specimens in duplicate within 4 h by a variation of the full procedure.