Question

what type of ion exchange would you select to separate amino acids and what pH conditions would you select ? 2- offer alternative methods from literature?

Answer 1

Anion exchange chromatography.

All appropriately charged proteins will bind the resin. For example, if an anion exchange resin is used at a pH of 7.5, in general, all proteins that have a pI < 7.5 will carry a net negative charge and will bind the positively charged resin. A salt gradient is then used to separate the protein of interest from other bound proteins — proteins will be eluted in an order depending on their net surface charge. Proteins with pI values closer to 7.5 will elute at a lower ionic strength, and proteins with very low pI values will elute at a high salt concentration.