Ion Exchange Chromatography

Ion exchange chromatography separates biomolecules like proteins based on their net charge. In anion exchange chromatography, the stationary phase is charged positively. Therefore, negatively charged biomolecules bind to the stationary phase. In cation exchange chromatography, the stationary phase is charged negatively. Thus, positively charged biomolecules bind to the stationary phase.

Ion exchange chromatography is a universal tool that can be applied in many purification processes. For example, in mAb processes, it is used to polish chromatography following the capture step. The most common examples are virus removal, DNA removal,숙주세포 단백질 removal, aggregate removal, and 내독소 removal. For other modalities, ion exchange chromatography is also commonly used as capture step, for example, viruses, VLPs, and pDNA. 

Usually, with increased salt content, the charge of the stationary phase and, therefore, the ability to bind, decreases. Typically, high salt conditions are also used for the elution. Ion exchangers that are considered salt-tolerant can bind, at higher salt concentrations than traditional ion exchangers. Salt-tolerant stationary phases are easier to implement and reduce or eliminate the need for dilution for adjustment steps.

If the pH of the medium is above the isoelectric point of the biomolecule, the biomolecule has a negative net charge. If the pH of the medium is below the isoelectric point of the biomolecule, it has a positive net charge. The pH of the medium is decisive for the binding conditions of the biomolecule to the stationary phase.

싸토리우스 offers ion exchange ligands on membranes, resins, and monoliths. The choice of matrix is dependent on the use case. Resins offer the best performance for smaller molecules, while membranes and monoliths offer the best performance for larger molecules or whenever high flow rates are required. Our experts are happy to assist in selecting the right product.