gel filtration 1

Gel Filtration
Biomolecules are purified using chromatography techniques that separate them according to differences in their specific properties, as shown:
Property Technique
Size Gel filtration (GF),also called size exclusion
Charge Ion exchange chromatography (IEX)
Hydrophobicity Hydrophobic interaction chromatography (HIC)
Reversed phase chromatography (RPC)
Biorecognition Affinity chromatography (AC)
(ligand specificity)
Gel Hydrophobic Ion exchange Affinity Reversed
Filtration interaction phase

gel filtration has played a key role in the purification of enzymes, polysaccharides, nucleic acids, proteins and other biological macromolecules. Gel filtration is the simplest and mildest of all the chromatography techniques and separates molecules on the basis of differences in size.
Separation by Gel Filtration:
Gel filtration medium is packed into a column to form a packed bed. The medium is a porous matrix in the form of spherical particles that have been chosen for their chemical and physical stability, and inertness (lack of reactivity and adsorptive properties). The packed bed is equilibrated with buffer which fills the pores of the matrix and the space in between the particles. The liquid inside the pores is sometimes referred to as the stationary phase and this liquid is in equilibrium with the liquid outside the particles, referred to as the mobile phase. It should be noted that samples are eluted isocratically, i.e. there is no need to use different buffers during the separation. However, a wash step using the running buffer is usually included at the end of a separation to facilitate the removal of any molecules that may have been retained on the column and to prepare the column for anew run.