*3.6.5 Partition chromatography*

It is a kind of chromatography method to separate components by using different partition coefficients between stationary phase and mobile phase, which are immiscible liquids. Partition chromatography could be divided into normal phase chromatography and reverse phase chromatography. The polarity of stationary phase is stronger than that of mobile phase in normal phase partition chromatography, which is mainly used to separate polar and moderately polar molecular compounds. Carriers commonly used in normal phase distribution chromatography include silica gel, diatomite, cellulose powder, etc. Silica gel with water content of more than 17% can be used as a carrier for partition chromatography because of its loss of adsorption. It is the most widely used carrier for partition chromatography. In reverse phase partition chromatography, the polarity of mobile phase is stronger than that of stationary phase. The commonly used stationary phase is octadecylsilylated silica (ODS). The mobile phase is usually methanol-water or acetonitrilewater system, which is mainly used for the separation of nonpolar and moderately polar molecular compounds.
