Preparation of an Ion-Exchange Chromatographic Support by A “Grafting From” Strategy Based on Atom Transfer Radical Polymerization

Abstract

A new "grafting from" strategy based on surface-initiated atom transfer radical polymerization (ATRP) was first used for the preparation of a polymer-based ion-exchange support for HPLC. The most important property of the proposed method is to be applicable for the synthesis of any type of ion exchanger in both the strong and the weak forms. Monodisperse, porous poly(glycidyl methacrylate-co-ethylene dimethacrylate), poly(GMA-co-EDM) particles 5.8 mum in size were synthesized by "modified seeded polymerization". Poly(dihydroxypropyl methacrylate-co-ethylene dimethacrylate), poly(DHPM-co-EDM) particles were then obtained by the acidic hydrolysis of poly(GMA-co-EDM) particles. The ATRP initiator, 3-(2-bromoisobutyramido)propyl(triethoxy)silane was covalently attached onto poly(DHPM-co-EDM) particles via the reaction between triethoxysilane and diol groups. In the next stage, the selected monomer carrying strong cation exchanger groups, 3-sulfopropyl methacrylate (SPM), was polymerized on the initiator-immobilized particles via surface-initiated ATRP. The degree of polymerization of SPM (i.e., length of polyionic ligand) on the particles was precisely controlled by adjusting ATRP conditions. Poly(SPM)-grafted poly(DHPM-co-EDM) particles obtained with different ATRP formulations were tried as chromatographic packing in the separation of proteins by ion-exchange chromatography. The proteins were successfully separated with higher column yields with respect to the previously proposed materials. The plate heights between 100 and 150 mum were achieved with the column packed with the particles carrying the shortest poly(SPM) chains. The plate height showed no significant increase with increasing flow rate in the range of 0.5-16 cm/min.

A New Stationary Phase Prepared from Ground Silica Monolith Particles by Reversible Addition-Fragmentation Chain Transfer Polymerization

“…[11][12][14][15] It is interesting to note that an initiator was attached to organic monolith particles instead of silica, and a polymer layer with ion exchange capability was added by ATRP in a specific study. 17 The details of principles and applications of ATRP are referred to some review articles. [18][19] Briefly, a catalytic mixture of cuprous/cupric halides and an amine base is used to activate polymerization on the silica surface with a halogen-containing initiator.…”

A cation‐exchange material for protein separations based on grafting of thiol‐terminated sulfopropyl methacrylate telomers onto hydrophilized monodisperse divinylbenzene particles

“…Comparative studies of commercial ion exchange sorbents show the vast number of materials available [1]. The introduction of ion-exchange functionality can be accomplished by a number of different strategies such as coating procedures [2], and "grafting from" [3,4] and "grafting to" alternatives [5] including the use of ring-opening methathesis polymerization [6]. Modifications of surface groups with various low molecular weight reagents have also been reported including the reaction of surface hydroxyl groups with sodium hydrogen sulfite [7] or phosphoryl chloride [8], and FriedelCraft acylation to produce sulfoacylated divinylbenzene (DVB) particles [9].…”

Ion‐exchanger synthesis using reversible addition‐fragmentation chain transfer polymerization

“…Several multistage polymerization protocols, "Activated Swelling Method", "Staged Shape Template Polymerization", and "Modified Seeded Polymerization" were proposed for the synthesis of monodisperse-porous particles in the micron size range [1 -5]. Most of the ionexchanger supports were obtained by surface modification protocols using activation agents or free radical polymerization techniques for linking of polyionic ligands to the particles [5]. A group of new ion exchangers for the separation of biopolymers was proposed in which the ionic groups were exclusively located on linear polymer chains grafted onto the support surface [6].…”