Particulate poly(glycidyl methacrylate-co-ethylene dimethacrylate) material for protein separation by anion-exchange chromatography

Abstract

New materials with different structures are being developed in order to be used in protein separation by ion exchange chromatography. Materials for beds are becoming of smaller particulate size, at the expense of lower permeability, in order to obtain better peak resolution during separation. On the other hand, polymeric organic monoliths, obtained by “in situ” polymerization, have been synthethized in recent years for similar purposes. In this work, a variety of poly(glycidyl methacrylate-co-ethylene dimethacrylate) resin has been synthetised by “in situ” polymerization, milled and classified in order to verify its behaviour when used at particulate state in protein separation by ion exchange chromatography, even at semipreparative scale, which is not possible to carry out using monoliths. The particulate and classified material was aminofunctionalized with diethylamine and then properly characterized in order to determine its physical properties and evaluate its separation performances once packed in chromatographic columns. The results show that the material obtained presents good permeability and favourable equilibrium isotherms. Kinetics follows the pore diffusion model, giving diffusion coefficients similar to others reported for several commercial materials. The axial dispersion coefficients obtained at different flow rate allow to forecast a reasonably good behavior in the anion exchange chromatographic fractionation of proteins, as it was proved with egg white proteins at laboratory and semipreparative scale.