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Mobile phase – the phase that moves in a definite direction. It may be a liquid (LC and capillary electrochromatography, CEC), a gas (GC), or a supercritical fluid (supercritical-fluid chromatography, SFC). The mobile phase consists of the sample being separated/analyzed and the solvent that moves the sample through the column.
The mobile phase is generally a mixture of non-polar organic solvent, while the stationary phase is polar inorganic solvent water. Here, paper is used to support the stationary phase, water. Polar water molecules are held inside the void space of the cellulose network of the paper. The difference between TLC and paper chromatography is that the ...
The sample is deposited on the plate, which is eluted with a solvent or solvent mixture known as the mobile phase (or eluent). [3] This solvent then moves up the plate via capillary action. [4] As with all chromatography, some compounds are more attracted to the mobile phase, while others are more attracted to the stationary phase. [5]
The organic solvent is called also a modifier, since it is added to the aqueous solution in the mobile phase in order to modify the polarity of the mobile phase. Water is the most polar solvent in the reversed phase mobile phase; therefore, lowering the polarity of the mobile phase by adding modifiers enhances its elution strength.
In chromatography, the retardation factor (R) is the fraction of an analyte in the mobile phase of a chromatographic system. [1] In planar chromatography in particular, the retardation factor R F is defined as the ratio of the distance traveled by the center of a spot to the distance traveled by the solvent front. [2]
Gas chromatography is the process of separating compounds in a mixture by injecting a gaseous or liquid sample into a mobile phase, typically called the carrier gas, and passing the gas through a stationary phase. The mobile phase is usually an inert gas or an unreactive gas such as helium, argon, nitrogen or hydrogen. [1] The stationary phase ...
See also Aqueous normal phase chromatography. It is commonly believed that in HILIC, the mobile phase forms a water-rich layer on the surface of the polar stationary phase vs. the water-deficient mobile phase, creating a liquid/liquid extraction system. The analyte is distributed between these two layers.
This is why as the mobile phase, called an eluate, passes out of the column, it typically flows into a detector or is collected by a fraction collector for compositional analysis. Predicting and controlling the order of elution is a key aspect of column chromatographic and column electrophoretic methods.