What is ion exchange chromatography? Ion-exchange chromatography (IEC) is an important analytical technique that is frequently utilized for the separation and determination of ions and…
Ion-exchange chromatography (IEC) is an important analytical technique that is frequently utilized for the separation and determination of ions and polar molecules on the basis of their affinity towards the ion exchanger.
Here, Stationary phase = A resin; Mobile phase = An eluent
Ion exchange chromatography along with the ion partition/interaction and ion-exclusion chromatography is an important component of ion chromatography.
Ion exchange chromatography is applicable for various charged molecules such as large proteins, amino acids, and small nucleotides.
The principle of separation is based on the reversible exchange of ions between the ions present in the sample and those available in the ion exchange resin. Mainly, ion exchange separations take place in a column covered with an ion exchanger.
Based on the charge on the ion-exchange ligands, Ion exchange chromatography is divided into two major types:
Anion exchange chromatography utilizes a positively charged ion exchange resin that has an affinity towards overall negative surface charge molecules.
In cation exchange chromatography, a negatively charged ion exchange resin is utilized that has an affinity towards molecules with overall positive surface charges.
Cation vs anion exchange chromatography:
|Cation exchange chromatography, as well as Anion exchange chromatography, can be employed for both preparative and analytical purposes. They also can segregate a large number of molecules from amino acids and nucleotides to large proteins.||Cation exchange chromatography is mainly used for proteins that possess a net positive charge at a pH below their isoelectric point to be bound. On the other hand, Anion exchange chromatography is used for proteins with a net negative charge at a pH above their isoelectric point to be bound.|
A typical ion exchange column chromatography comprises of:
Figure: A systematic ion exchange chromatography diagram; Image courtesy: uspbpep.com
In ion exchange chromatography, a conductivity detector is regarded as the most common and beneficial detector. Finally, the result received is reserved.