ESIEX-Electrical Swing Ion Exchange a Process Coupling Ion Exchange, Carbonic Acid Elution, and Electrochemical Regeneration
Résumé
A process which can be used for purification of a peptide is presented. This process is called ESIEX: Electrical Swing Ion Exchange. The principle of this process is based on a three steps cyclic mode, which avoids using pH buffers or generating wastes. The experimental set-up consists of an electrodialysis apparatus in which the cells are filled with anion exchange resins. Carbon dioxide dissolved in water is used as "green eluent.'' Peptide is obtained pure. Assuming that equilibria in solution play a major role on the global separation factor compared to affinities for the support, peptides which can be fixed in a step but also eluted in another step should satisfy with a criterion: pK(a1) < pK(A-/A) < pK(a2). The peptide dissociation constant pK(A-/A) must be between the two dissociation constants of carbonic acid, that is, 6.35 and 10.35 (at 298 K).