Phenylalanine functionalized zwitterionic monolith for hydrophobic interaction electrochromatography

Abstract

A novel phenylalanine (Phe) functionalized zwitterionic monolith for hydrophobic electrochromatography was prepared by a two-step procedure involving the synthesis of glycidyl methacrylate based polymer monolith and subsequent on-column chemical modification with Phe via ring-opening reaction of epoxides. Benefitting from the hydrophobicity of both methacrylate-based matrix and aromatic group of Phe, this monolith could exhibit good hydrophobic interaction for the separation. Typical RP chromatographic behavior was observed toward various solutes. The well-controlled cathodic or anodic EOF of the prepared column could be facilely switched by altering the pH values of running buffers. The separation mechanism of this Phe functionalized zwitterionic monolith is discussed in detail. Two mixed-mode mechanisms of RP/cation exchange and RP/anion exchange could be further realized on the same monolith in different pH condition of the mobile phase. Versatile separation capabilities of neutral, basic, and acidic analytes have been successfully achieved in this zwitterionic monolith by CEC method.

Quinine‐modified polymer monolithic column with reversed‐phase /strong anion‐exchange mixed‐mode for pressurized capillary electrochromatography

“…Higher ACN content in the mobile phase is advantageous for SAX interaction. The ion‐exchange elution for gallic acid was weakened and caused a slight increase of log k′ , which was similar to that reported previously . Additionally, a higher ACN content in the mobile phase could also suppress π–π stacking interaction.…”

“…To expand the preparation of MMCs, post‐polymerization modification as a versatile access to the functionalization of monolithic columns, has been developed and used intensively . With the ring‐opening reaction of glycidyl methacrylate (GMA), various amine compounds such as phenylalanine, cystamine and epinephrine have been chemically decorated on GMA‐based monoliths and applied to chromatographic separation with mixed‐mode mechanisms including RP and weak anion–exchange (WAX) interactions . Based on the special aliphatic amine like triethylamine, cationic ammonium groups were formed via the nucleophilic reaction of tertiary amine with GMA, and the resultant positively charged monoliths were further used for strong anion–exchange (SAX) separations .…”

Epinephrine‐modified methacrylate monolithic column with fumed silica nanoparticle for pressurized capillary electrochromatography

“…Within the two main types of monolithic materials, polymer‐based monoliths have several advantages compared to silica‐based ones and that includes: a simpler and faster preparation, versatile choices of surface modification and stability in a wider pH range. Among a variety of organic polymer‐based monoliths, poly(GMA‐EDMA) monoliths, with a straightforward and efficient derivatization at the epoxy group, is the most common one. Different functionalities at the epoxy‐groups of GMA‐based monoliths, such as amino acids , quinine and a variety of chiral reagents , have been reported to provide monoliths with different chromatographic properties.…”

Ionic liquid-based zwitterionic organic polymer monolithic column for capillary hydrophilic interaction chromatography

“…13 Several methacrylate-based monolithic columns have been prepared for hydrophilic interaction liquid chromatography separation. 16,17 The applicability of ionic liquid-based organic polymer monoliths in HILIC separation has been rarely explored. 16,17 The applicability of ionic liquid-based organic polymer monoliths in HILIC separation has been rarely explored.…”