Desalting Columns

Disposable or reusable gel filtration chromatography columns for use in protein biology or DNA extraction and purification, for the fractional purification of proteins, nucleic acids, and other macromolecules from low molecular-weight buffer salts and reagents.

Desalting columns are special kinds of gel filtration (exclusion) chromatography columns suitable for the fractional purification of proteins, nucleic acids, and other macromolecules. Their use offers a more convenient and quicker alternative to dialysis.

Desalting columns may be disposable or reusable plastic or glass columns prepacked with beads of a suitable media, typically polysaccharide (Sephadex), or porous polyacrylamide that are more resistant to enzymatic degradation. The beads have defined molecular weight cut-off (MWCO) exclusion points (typically around 6000 Da) that trap, retain, and slow down the elution of small molecules below the MWCO, but exclude and therefore do not impede the more rapid elution of larger macromolecules such as proteins.

Desalting columns can achieve high sample recovery yields of >95%, with column capacities ranging from 5 μL to 10 mL that are suitable for applied sample volumes anywhere between 2 μL and 4 mL.

Types of Desalting Columns
• Columns designed for simple gravity flow
• Spin columns designed especially for centrifugation
• Pressure-compatible columns designed for use with suitable pumps or with integrated preparative LC systems

How Are Desalting Columns Used?
• Removal of salts from protein samples
• Buffer exchange prior to downstream electrophoresis or affinity chromatography
• Removal of unreacted radioactive labels
• Removing phenol or free nucleotides from nucleic acid preparations
• Removing of primers or dyes from PCR or sequencing reactions
• Removal of other low molecular weight compounds such as cross-linking, labelling or derivatization reagents, cofactors, inhibitors, or other contaminants