Method Development for the Separation of Phospholipids by Subcritical Fluid Chromatography

Super/subcritical Fluid Chromatography (SFC) has been used successfully for the analysis of a variety of compounds including foods, polymers, and pharmaceuticals. 1-7 Supercritical carbon dioxide exhibits solvating power comparable to hexane and has been primarily utilized as a fluid for the separation of relatively non-polar compounds. 8 For this reason, many SFC methods have been developed as substitutes for normal-phase HPLC methods. Commonly used normal-phase HPLC mobile phases consist generally of chlorinated solvents such as chloroform and methylene chloride. Traces of water in these mobile phases cause retention times to fluctuate in the normal-phase mode. These solvents also present an environmental hazard, which can be eliminated in part by using a mobile phase of carbon dioxide which may or may not have been modified with a small percentage of organic solvent. Additionally, the quantity of solvent required and the high disposal costs commonly encountered with many normal-phase HPLC solvents may be dramatically reduced by employing carbon dioxide based mobile phases.