—Non-adsorption method, easy operation, only one buffer solution required. 

Classification and Characteristics of Gel Filtration Chromatography:

—Group Separation (desalination/buffer exchange); The sample volume can reach 30% of the column volume. 

—Fine Separation (aggregate removal, separation of proteins of different molecular weights); Sample volume of 0.5-4%, column bed height is higher than 60cm.

—Good controllability, high selectivity, high load, high recovery, good physical and chemical stability, simple in situ cleaning

Classification and Characteristics of Ion Exchange Media:

—Composed of the base frame and the functional group, the ion exchange medium is divided into cation exchange and anion exchange according to the charge properties of the functional group, and is classified into strong ion exchange group and weak ion exchange group according to its electric strength in the solution.

—The type and density of the ion-exchange group determine the selectivity and load of the medium. The properties of the base frame determine the resolution and mechanical properties of the medium.

(1)Type and Concentration of Salt 
Some ions that form the salt in the buffer have a stabilizing effect on protein conformation, such as SO42-, which can improve the stability of protein structure, decrease the solubility of protein, have a salting out effect on protein, and enhance the hydrophobic effect between protein and ligand. Some ions have an un-stabilizing effect on protein conformation, such as Cl- and Ca2+, which can increase protein solubility, and these ions have a strong elution ability. The properties of salting out and salting in can be used as the basis for choosing the equilibrium and elution conditions of hydrophobic media.  

(2)Temperature
In the process of hydrophobic chromatography, the temperature goes up, there are conformational changes in biomacromolecules, and the hydrophobic effect is enhanced, which helps to improve the separating degree of column chromatography. However, for bioactive substances, high temperature will cause denaturation and deactivation, so hydrophobic chromatography is often conducted under a normal temperature or low temperature. It is suggested that hydrophobic chromatography should be conducted under the condition of constant temperature to avoid the influence of temperature changes on the tomographic results. 

(3)pH
The mobile phase of hydrophobic chromatography is usually a phosphate buffer with a neutral pH value. The interaction between protein and hydrophobic group decreases with the increase of pH, because the charge of acidic group of protein increases gradually with the increase of pH, and the hydrophilicity increases. However, the hydrophobicity of proteins is usually not changed by adjusting the pH of solution in hydrophobic chromatography.

—High efficiency, speediness; High selectivity; High resolution; Over 90% purity can be achieved usually through one-step purification; High recovery rate

Composition of Affinity Medium:

—Base Frame：Inert materials coupled with ligands, such as Bestarose FF, Bestarose HP, etc.
—Connecting Arm：Reduce the steric-hindrance effect, greatly increase the adsorption efficiency of ligands and biomacromolecules to be separated;  
—Ligands：Substances that interact specifically with a target molecule.