Preparation and evaluation of a polymer-based sulfobetaine zwitterionic stationary phase.

We describe a polymer-based sulfobetaine zwitterionic stationary phase for hydrophilic interaction liquid chromatography (HILIC). It was prepared by grafting acrylamide-type sulfobetaine monomer instead of common methacrylate-type sulfobetaine onto hydrolysed poly (glycidyl methacrylate-divinylbenzene) (GMA-DVB) microspheres via pendant double bonds of DVB. The phase has been characterized by elemental analysis, scanning electron micrograph and N2 adsorption-desorption experiment. It shows wider pH tolerance range (from 2 to 12) and excellent separation ability towards common strong polar analytes such as nucleosides and nucleic bases, water-soluble vitamins, amino acids, inorganic anions and cations. Notably, it exhibits negligible baseline noise level (~0.15 pA) under typical HILIC mobile phase. Excellent selectivity in separation of α- and β-anomers of reducing sugars and lactose/lactulose has also been observed.

Liu X ，Jiang Y ，Zhang F ，Li Z ，Yang B ... -  《-》

Synthesis and evaluation of sulfobetaine zwitterionic polymer bonded stationary phase.

Zwitterionic polymer stationary phases have attracted increasing attention in hydrophilic interaction chromatography (HILIC). In this work, a zwitterionic sulfobetaine functionalized polyacrylamide stationary phase (named TENS) based on porous silica particles was prepared via controlled surface initiated reversible addition-fragmentation transfer (RAFT) polymerization. Instead of traditional methacrylate type sulfobetaine monomer, acrylamide type sulfobetaine monomer, which has higher chemical stability and hydrophicility, was employed in this work. The characterization of elemental analysis and solid-state 13C cross polarization/magic-angle-spinning nuclear magnetic resonance indicated the successful preparation of TENS stationary phase. Meanwhile, scanning electron microscope (SEM), nitrogen adsorption experiment and study of size exclusion performance were conducted, revealing that the surface initiated polymerization was well controlled. For better understanding of TENS material under HILIC mode, chromatographic evaluation of TENS material was performed, among which, TENS material exhibited good hydrophilicity and chemical stability. To further study the applicability of TENS material, saccharides which were considered as challenging targets in HILIC, were chosen as tested analytes. Various saccharide samples, including fructooligosaccharide, trisaccharide isomers and ginsenosides, were well separated on TENS material. Moreover, TENS material displayed good selectivity for the enrichment of glycopeptides. These results demonstrated the capability of TENS as a promising material in glycomics and glycoproteomics.

Yu D ，Guo Z ，Shen A ，Yan J ，Dong X ，Jin G ，Long Z ，Liang L ，Liang X ... -  《-》

A polymer-based zwitterionic stationary phase for hydrophilic interaction chromatography.

We describe a novel polymer-based zwitterionic stationary phase for hydrophilic interaction chromatography (HILIC). It is prepared by chemical modification of poly (glycidyl methacrylate-divinylbenzene) (GMA-DVB) by converting epoxide groups of microsphere surface to diol groups via hydrolysis, then clicking cysteine onto the microsphere with pendant double bonds of microsphere surface via "thiol-ene" click chemistry. The phase has been characterized by scanning electron micrograph, elemental analysis and zeta potential measurement. Diol and zwitterionic group (carboxylate and amine group associated with cysteine) onto the surface of GMA-DVB microspheres make them possess good hydrophilicity, as supported by effective separation towards common polar analytes. It shows good stability at alkaline solution (e.g. pH 10) and negligible bleed (e.g. only 1.7-fold blank and ~55-fold lower than a commercial silica-based polar phase tested with the minimal bleed level). Such phase exhibits specific separation selectivity to ionic analytes and simultaneous separation of anions and cations is achieved in the retention order of I- < NO3- < Choline < Br- < Cl- < K+< Na+.

Li S ，Li Z ，Zhang F ，Geng H ，Yang B ... -  《-》

Simultaneous chromatographic separation of the anomers of saccharides on a polymer sulfobetaine zwitterionic stationary phase.

Yang M ，Mei H ，Jiang Y ，Zhang F ，Yu Z ，Yang B ... -  《-》

A lysine and amide functionalized polymer-based polar stationary phase for hydrophilic interaction chromatography.

A novel polymer-based polar stationary phase for hydrophilic interaction chromatography (HILIC) is described. It was obtained by grafting lysine and acrylamide onto poly (glycidyl methacrylate-divinylbenzene) (GMA-DVB) microspheres via ring-opening reaction of epoxy groups and free radical polymerization with pendant double bonds of the microspheres. Multiple types of polar groups including zwitterionic (carboxylate and amine), amide and diol onto the microspheres make them highly hydrophilic. It showed typical HILIC character and good separation performance towards model polar analytes. Negligible bleed level under gradient elution mode (up to 50% fraction of water) was observed. It also exhibited specific separation selectivity to ionic analytes and simultaneous separation of anions and cations could be achieved in ideal electrostatic selectivity elution order, e.g. I-< NO3- <Br- <Cl- or K+< Na+ < Li+.

Yu Z ，Li Z ，Zhang F ，Yang B ... -  《-》