What are the main phases of Column Chromatography?

There are two main phases of chromatography – the stationary phase and the mobile phase.

Stationary Phase
An adsorbent or immobile surface inside the column acts as the stationary phase. Agarose beads act as the stationary phase in column chromatography. The highly porous surface of the agarose beads allows the analyte and solvent to migrate through the pores.

Mobile Phase
The mobile phase consists of a mixture of analyte and solvent that moves through the column. The action of this mixture running through the column is considered the mobile phase. As it passes through the column, the individual components of the analyte interact differently with the immobile surface in the column. Each component spends more or less time interacting with the stationary phase depending on its polarity. This results in the components of the analyte to begin separating and continue moving slowly toward the end of the column at different speeds. 

Depending on of their polarity they spend more or less time interacting with the stationary phase and are thus retarded to a greater or lesser extent. This leads to the separation of the different components present in the sample. Each sample component elutes from the stationary phase at a specific time, its retention time. As the components pass through the detector their signal is recorded and plotted in the form of a chromatogram.