Supercritical Fluid Chromatography (SFC) is a form of normal phase chromatography that is used for the analysis and purification of low to moderate molecular weight, thermally labile molecules. It can also be used for the separation of chiral compounds. Principles are similar to those of high performance liquid chromatography (HPLC), however SFC typically utilizes carbon dioxide as the mobile phase; therefore the entire chromatographic flow path must be pressurized.
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SFC finds use in industry primarily for separation of chiral molecules, and uses the same columns as standard HPLC systems. SFC is now commonly used for achiral separations and purifications in the pharmaceutical industry.[1]
SFC utilizes carbon dioxide pumps that require that the incoming CO2 and pump heads be kept cold in order to maintain the carbon dioxide in a liquid state where it can be effectively metered at some specified flow rate. The chemist uses software to set mobile phase flow rate, co-solvent composition, and column temperature. In addition, SFC provides an additional control parameter - pressure - by using an automated back pressure regulator. From an operational standpoint, SFC is as simple and robust as HPLC but fraction collection is more convenient because the primary mobile phase evaporates leaving only the analyte and a small volume of polar co-solvent.
Similar to an HPLC system, SFC can use a variety of detection methods including UV/VIS, mass spectrometry, FID (unlike HPLC) and evaporative light scattering.
Any molecule that will dissolve in methanol or a less polar solvent can be analyzed using SFC, including polar solutes.[Ref needed]
The mobile phase is composed of high pressure liquid or supercritical carbon dioxide, however modifiers are added which can be used to change the chromatography, these are typically alcohols like methanol, ethanol or isopropyl. Other solvent such as acetonitrile and chloroform can be used as modifiers. The solvent limitations are system and column based.