1991 Volume 7 Issue Supple Pages 241-244
Using a primary mobile phase of supercritical carbon dioxide, the effects of various organic solvents as modifiers are studied. The on-line mixed mobile phase delivery for capillary SFC is served by a system which was modified a Jasco SFC Super-200 by incorporating a double-stage flow splitter. Organosulfur compounds were separated on a capillary column (SB-Phenyl-5, 50μmx10m, 0.25μm film thickness). The mobile phases which various modifiers up to 0.15mL/min were mixed with a constant supercritical carbon dioxide flow (2.0mL/min at pump outlet) were used to separate the test solute mixture. Selective detection of organosulfur compounds has been carried out with a dual-flame photometric detector without interference of organic modifier solvents. Modifier - pressure programming are shown to yield decreased analysis time with increasing modifier concentration. But early eluted compounds (thiophenol and benzo[b]thiophene) were more retained since fluids with modifier were probably not supercritical at an initial SFC condition. Also approximately linear relationships existed between capacity factors (k') and the solubility parameter of organic modifiers.
