In this type of chromatography, a stationary phase contains solid adsorbent while the mobile phase contains the liquid or mixture of compounds. For the chromatographic separations, the adsorbent is placed in vertical glass column and the mixture is flow down through the column in the mobile phase. The gravitational force or external pressure is used to pass the liquid through the column. It gives highly effective results in isolating the desired compounds from a mixture. The adsorbents such as Silica gel and alumina
are commonly used for column chromatography.
These adsorbents are used in different mesh sizes which are selected based on the complexity of the mixture, water content present in it as well as on the molecules of the desired compound. The size of the adsorbent affects the flow of solvent through the column. It means that adsorbent with higher mesh size is used for flash chromatography where solvent flow down the column using positive air pressure, while the adsorbent with lower mesh size is suitable for gravity chromatography where gravity helps the solvent to flow down the column.