Pretreatment of Chromatography Media
In the industrial products of ion exchangers, a small amount of organic oligomers and some inorganic impurities are often contained, which will gradually dissolve and release at the initial stage of use, affecting the quality of the target product. Therefore, industrial grade ion exchangers must be pretreated prior to use.
The general-purpose ion exchange resin is usually treated with acid or alkali, and can be treated with 1~2 mol/L hydrochloric acid and sodium hydroxide solution in an alternate 4~6 times resin bed volume, between acid and alkali treatment. Wash with deionized water until neutral. For macroporous resins, it is also necessary to treat them with an organic solvent such as ethanol or acetone to remove organic residues used in the production process. Pretreatment of the separation medium not only improves its working capacity, but also improves the purity of the separated product. The pretreated resin should eventually be converted to the applicable ionic form during the separation process.
For biochemical-specific ion exchangers, a polysaccharide-based medium is generally stored in 20% ethanol. In order to separate the medium to minimize the change in pH during the separation process, it is necessary to wash with a large amount of deionized water and then equilibrate with a buffer.
The pretreatment of the separation medium can be carried out in a column or in a vessel such as a beaker. When pretreatment is carried out in the column, or when the solution system changes and the operating temperature changes, air bubbles often occur, especially when a column having a smaller inner diameter is used. Once the bubbles appear, they must be removed in time, otherwise the chromatographic process will have a significant impact.