The principle of chromatography is based on 2 phases: the mobile phase which drives the sample and the stationary phase which allows its purification. The chromatography resins constitute this stationary phase.
There are different types of chromatography depending on the type of resin used. The four main types of chromatography include affinity chromatography, ion exchange chromatography (IEX), hydrophobic interaction chromatography (HIC), and size exclusion chromatography (SEC). Most purification systems require the use of several of these types of chromatographic procedures to achieve the purity required for downstream applications. The choice of the most appropriate chromatographic method (s) and the order of these methods is essential in the optimization of a protein purification method.
|Type of chromatography||Separation principle||Interaction||Elution|
|Affinity||Specific interaction||No competitive ligand||Competitive ligand (specific), breakdown of protein / protein interactions by change of conditions (non-specific)|
|Ion exchange||Net surface charge||Low ionic strength||High ionic strength, increasing (cations) or decreasing (anions) pH|
|Hydrophobic interactions||Hydrophobicity||High ionic strength||Low ionic strength|
|Size exclusion||Hydrodynamic Radius|