chapter  12
22 Pages

High Temperature Gas–Liquid Chromatographic Profiling of Plasma Lipids: A Student Exercise

The analysis of blood lipids constitutes an important adjunct to clinical diagnosis of hypercholesterolemia and hypertriglyceridemia, which are believed to be important risk factors for heart disease and stroke.1 Various chemical and enzymatic methods have been utilized in the determination of plasma lipids, some of which have been automated and are currently widely applied.2 The development of direct gas-liquid chromatography (GLC) analysis of total lipid extracts of plasma or serum is based on a successful chromatography of the individual components of the plasma total lipid mixture.3 Due to the advantageous distribution of the molecular weights and functional groups of the neutral lipid moieties, the plasma lipids are especially well suited for programmed temperature resolution on nonpolar GLC columns. For optimum resolution and recovery, the lipid extracts of whole plasma or individual lipoprotein classes are subjected to dephosphorylation and trimethylsilylation (TMS) prior to GLC. Specifically, the GLC resolution provides a quantitative estimate of plasma cholesterol, triacylglycerols and phospholipids, along with the degree of unsaturation of the major fatty acid moieties. This approach to the quantitative GLC analysis of plasma lipids, which was originally proposed over 30 years ago,4 has been extensively utilized in plasma lipid analyses in health and disease, and the results have been reviewed.5