The chromatographic properties of a mixed-bed stationary phase combining reversed-phase and strong anion exchange properties

Mixed Ion Exchange Supports as Useful Ion Exchangers for Protein Purification: Purification of Penicillin G Acylase from Escherichia coli

“…They may be produced in one column by mixed-bed, mixed-ligand (two or more different functionalized ligands on the same substrate particle), or mixed-mode packings (two or more types of interaction sites or modes on the same surface-attached moiety). , Several workers have designed systems to simultaneously separate anions and cations using a series arrangement of anion- and cation-exchange columns or mixed beds of cation- and anion-exchange particles . Another approach is to use the oppositely charged sites of zwitterionic ligands, either covalently bound to support particles or dynamically sorbed from the mobile phase onto a C 18 stationary phase. , Much of this work has involved organic ions, for which dispersion as well as Columbic interactions come into play …”

Multifunctional Zwitterion-Exchange Stationary Phase for HPLC

“…Interestingly, the k' of a strong organic acid, p-toluenesulfonic acid, decreased rapidly with increasing the pH value of mobile phase, while that of zwitterion compounds, phenylalanine, leucine and alanine, had a volcano at pH about 4. (1) p-toluenesulfonic acid, (2) benzylamine, (3) aniline, (4) benzoic acid, (5) 1-rkphthylaectic acid, (6) phenvlalanine, (7) aniline.…”

Demonstration of simultaneous anion-exchange and reversed-phase behavior on a strong anion-exchange column

“…And so it was of interest to show that some anion-neutral organic separations could be done in 100% aqueous mobile phases as was done on a strong cation-exchange column [4]. Lastly, while mixed-bed and designer mixed-ligand phases offer the ability to alter the ratio of ion-exchange-to-reversed-phase sites [9,10] most researchers will choose readily available commercial phases, and so we have employed such columns in this report.…”

“…Work employing serial columns [8] or a mixed-bed of reversed-phase and anion-exchange materials [9] has been successful in separating mixtures of anions and uncharged analytes in one run. The reversed-phase and anion-exchange mechanisms were shown to operate independently of each other in the mixed-bed column [9].…”

“…Work employing serial columns [8] or a mixed-bed of reversed-phase and anion-exchange materials [9] has been successful in separating mixtures of anions and uncharged analytes in one run. The reversed-phase and anion-exchange mechanisms were shown to operate independently of each other in the mixed-bed column [9]. Mixed ligand (C 8 and strong anionexchange appendages) [10] and multifunctional phases (different interaction sites on one attached ligand) [11] were also employed for both anions and neutral species.…”