EXTENDED USE OF SOLVENT VENTING INJECTION TECHNIQUES FOR LARGE SAMPLE VOLUMES AND COUPLED CAPILLARY COLUMNS IN SFC

The solvent venting injection technique has been tested for 1-mu-L injections of lipids in open tubular column SFC. No sample loss during solvent venting was experienced with a 7-m precolumn at elevated temperatures. The solvent venting technique has also been combined with gas purging to concentrate the sample on-line with SFC. Injections totalling 10-50-mu-L of sample have been performed. The solvent venting technique with minor modifications in the instrumentation was utilized for group separations of triglycerides. Different techniques for solute focusing were tested. The best peak shape was obtained by a combination of phase ratio and low temperature focusing.