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Carbon dioxide (CO 2) is the most used supercritical fluid, sometimes modified by co-solvents such as ethanol or methanol. Extraction conditions for supercritical carbon dioxide are above the critical temperature of 31 °C and critical pressure of 74 bar. Addition of modifiers may slightly alter this.
A supercritical fluid (SCF) is a substance at a temperature and pressure above its critical point, where distinct liquid and gas phases do not exist, but below the pressure required to compress it into a solid. [1]
[6] In laboratories, s CO 2 is used as an extraction solvent, for example for determining total recoverable hydrocarbons from soils, sediments, fly-ash, and other media, [7] and determination of polycyclic aromatic hydrocarbons in soil and solid wastes. [8] Supercritical fluid extraction has been used in determining hydrocarbon components in ...
It is called supercritical fluid. The common textbook knowledge that all distinction between liquid and vapor disappears beyond the critical point has been challenged by Fisher and Widom , [ 8 ] who identified a p – T line that separates states with different asymptotic statistical properties ( Fisher–Widom line ).
For example, “a fluid is considered to be ‘supercritical’ when its temperature and pressure exceed the temperature and pressure at the critical point”. In the studies of supercritical extraction, however, “supercritical fluid” is applied for a narrow temperature region of 1-1.2 T c {\displaystyle T_{c}} or T c {\displaystyle T_{c ...
Supercritical fluid chromatography (SFC) [1] is a form of normal phase chromatography that uses a supercritical fluid such as carbon dioxide as the mobile phase. [ 2 ] [ 3 ] It is used for the analysis and purification of low to moderate molecular weight , thermally labile molecules and can also be used for the separation of chiral compounds.
The Chemistry Development Kit (CDK) is computer software, a library in the programming language Java, for chemoinformatics and bioinformatics. [4] [5] It is available for Windows, Linux, Unix, and macOS. It is free and open-source software distributed under the GNU Lesser General Public License (LGPL) 2.0.
The extraction cell is filled with the solid sample to be examined and placed in a temperature-controllable oven. After adding the solvent, the cell is heated at constant pressure (adjustable between 0.3 and 20 MPa) up to a maximum temperature of 200°C and kept at constant conditions for a while so that equilibrium can be established.