“Click Chemistry” in the Preparation of Porous Polymer-Based Particulate Stationary Phases for μ-HPLC Separation of Peptides and Proteins

With the use of the copper(I)-catalyzed (3 + 2) azide-alkyne cycloaddition, an element of "click chemistry," stationary phases carrying long alkyl chains or soybean trypsin inhibitor have been prepared for use in HPLC separations in the reversed-phase and affinity modes, respectively. The ligands were attached via a triazole ring to size monodisperse porous beads containing either alkyne or azide pendant functionalities. Alkyne-containing beads prepared by direct copolymerization of propargyl acrylate with ethylene dimethacrylate were allowed to react with azidooctadecane to give a reversed-phase sorbent. Azide-functionalized beads were prepared by chemical modification of glycidyl methacrylate particles. Subsequent reaction with a terminal aliphatic alkyne produced a reversed-phase sorbent similar to that obtained from the alkyne beads. Soybean trypsin inhibitor was functionalized with N-(4-pentynoyloxy)succinimide to carry alkyne groups and then allowed to react with the azide-containing beads to produce an affinity sorbent for trypsin. The performance of these stationary phases was demonstrated with the HPLC separations of a variety of peptides and proteins.