Supercritical fluid (SF) was discovered 200 years ago, but the use of this fluid as a mobile phase in chromatography
only became popular fifty years ago. The development of the supercritical fluid chromatography (SFC) was progressing
slowly due to technological problems since ten years; the interest for this chromatographic mode has been growing
up as the construction of the SFC instruments is more or less similar with HPLC instruments. The main difference in
SFC is the installation of a back pressure regulator which is implemented to control the pressure above the critical pressure.
SFC is widely used in chiral chromatography where Polysaccharide phases are the most versatile in use. The mobile
phase is mainly composed by CO2 but the polarity can be increased by adding alcohol. The nature of the alcohol can
change drastically the selectivity. The choice of the best tandem stationary phase / mobile phase is difficult to predict.
Hence a full screening with different stationary phases and mobile phase solvents is often mandatory. For the achiral separation,
SFC is more and more used. Achiral SFC can be classified as normal phase mode, it means that stationary phases
are more polar than mobile phase and retention times decrease as polarity of the mobile phase increases. Most popular stationary
phases are silica linked with polar group such as aminopropyl, cyanoprpyl, diol or 2-ethylpyridine. Mobile phase
are generally composed by CO2 and methanol. SFC can be used as a complementary technique for reversed phase HPLC
or sometimes even to replace HPLC.
Keywords: Achiral, chiral, polysaccharide phases, SFC, Supercritical fluid (SF), supercritical fluid chromatography (SFC), HPLC, chiral chromatography, Reversed phase liquid chromatography (RP HPLC), evaporative light scattering detector (ELSD)
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