Desalting Columns
Desalting columns are special kinds of gel filtration (exclusion) chromatography columns used in protein biology or DNA extraction and purification for the fractional purification of proteins, nucleic acids and other macromolecules. Their use offers a more convenient and quicker alternative to dialysis.
Desalting columns are 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 daltons) which 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 over 95%, with column capacities ranging from 5μL to 10mL suitable for applied sample volumes anywhere between 2μL and 4mL.
What types of desalting column are available?
- 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
What are desalting columns used for?
- Removal of salts from protein samples
- Buffer exchange prior to downstream electrophoresis or affinity chromatography
- Removal of unreacted radioactive label
- 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 crosslinking, labelling or derivatisation reagents, cofactors, inhibitors and other contaminants