Liquid fluid chromatography

Liquid phase chromatography can use a supercritical fluid as an eluent. The solvent evaporates on leaving the column and allows detection by FID. At present, there are few instances in the petroleum industry using the supercritical fluid technique. 

Figure 12.22 SFC-GC analysis of aromatic fraction of a gasoline fuel, (a) SFC trace (b) GC ttace of the aromatic cut. SFC conditions four columns (4.6 mm i.d.) in series (silica, silver-loaded silica, cation-exchange silica, amino-silica) 50 °C 2850 psi CO2 mobile phase at 2.5 niL/min FID detection. GC conditions methyl silicone column (50 m X 0.2 mm i.d.) injector split ratio, 80 1 injector temperature, 250 °C earner gas helium temperature programmed, — 50 °C (8 min) to 320 °C at a rate of 5 °C/min FID detection. Reprinted from Journal of Liquid Chromatography, 5, P. A. Peaden and M. L. Lee, Supercritical fluid chromatography methods and principles , pp. 179-221, 1987, by courtesy of Marcel Dekker Inc.

Henry, M.C. and Yonker, C.R., Supercritical fluid chromatography, pressurized liquid extraction, and supercritical fluid extraction. Anal. Chem., 78, 390, 2006. 

Cortes, H. J., Campbell, R. M., Himes, R. P., and Pfeiffer, C. D., On-line coupled liquid chromatography and capillary supercritical fluid chromatography large-volume injection system for capillary SFC, ]. Microcol. Sep., 4, 239, 1992. 

In supercritical fluid chromatography (SFC) the mobile phase is a supercritical fluid, such as carbon dioxide [15]. A supercritical fluid can be created either by heating a gas above its critical temperature or compressing a liquid above its critical pressure. Generally, an SFC system typically has chromatographic equipment similar to a HPLC, but uses GC columns. Both GC and LC detectors are used, thus allowing analysis of samples that cannot be vaporized for analysis by GC, yet cannot be detected with the usual LC detectors, to be both separated and detected using SFC. SFC is also in other... 

Furthermore, supercritical CO2 does not behave as merely a mixture of liquid and gaseous CO2, but often exhibits an exceptional ability to solvate molecules in a specific way. The removal of caffeine from coffee relies on the chromatographic separation of caffeine and the other organic substances in a coffee bean supercritical fluid chromatography is a growing and exciting branch of chemistry. 

Electrochemical detectors (ECD) gas chromatography, 4 615 liquid chromatography, 4 622 6 387, 449 supercritical fluid chromatography, 4 631... 

Supercritical fluid chromatography employs supercritical fluid instead of gas or liquid to achieve separations. Supercritical fluids generally exist at conditions above atmospheric pressure and at an elevated temperature. As a fluid, the supercritical state generally exhibits properties that are intermediate to the properties of either a gas or a liqiud. Chapter 16 discusses various advantages of SFC over GC and HPLC and also provides some interesting applications. 

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