Hydrogel Coating with Temperature Response Retention Behavior and Its Application in Selective Separation of Liquid Chromatography

Abstract

We reporte the double-layer hydrogel-coated mesoporous silica material as a new stationary phase for liquid chromatography. The method of combining physical coating and chemical coating was to apply hydrogel coating on the surface of silica, and finally, a new type of liquid chromatography stationary phase with in situ coating of the functional hydrogel on silica was obtained. This hydrogel-functionalized liquid chromatography stationary phase also exhibits a certain temperature responsiveness. Experimental results show that this temperature response is mainly due to changes in the hydrogen bonding between the stationary phase and the analyte at different temperatures in the column oven, which leads to changes in retention behavior. The hydrogel-coated mesoporous silica microspheres showed excellent selectivity for many polar analytes. An excellent column efficiency was obtained (139 000 plates/m for terephthalic acid) after optimization of chromatographic conditions. In addition to rapid separation of some analytes, this new hydrogel stationary phase also has certain superiority in chromatographic performance compared with other new excellent liquid chromatography stationary phases functioned by three-dimensional cross-linking systems. The important thing is that this strategy is relatively easy to prepare a new stationary phase with different properties.

Click Chemistry for the Preparation of β-Cyclodextrin Grafting Uniform Spherical Covalent Organic Framework Materials for Chiral Separation

“…In addition, the van't Hoff equation was used to measure the enthalpy change (ΔH) and entropy change (ΔS) for the transfer of solutes from the mobile phase to the stationary phase. 43 First, the van't Hoff plots (see Figure 5) of alkylbenzenes and 1-phenylpropionic acid possessed a good linear relation, which proved that the separation mechanism did not change significantly during the temperature change. Then, a more positive ΔS and a more negative ΔH thermodynamically contribute to the transfer of the solute from the mobile phase to the stationary phase, resulting in the stronger retention of solute in the stationary phase.…”

“…Figures S5B,S6B show that the retention time of the analytes on the COF-modified column shortened gradually with rising column temperature, indicating the exothermic process under separation. In addition, the van’t Hoff equation was used to measure the enthalpy change (Δ H ) and entropy change (Δ S ) for the transfer of solutes from the mobile phase to the stationary phase . First, the van’t Hoff plots (see Figure ) of alkylbenzenes and 1-phenylpropionic acid possessed a good linear relation, which proved that the separation mechanism did not change significantly during the temperature change.…”

ZIF-8 Assisted Polyacrylamide Functionalized Silica Core-Shell Stationary Phase for Hydrophilic Interaction Liquid Chromatography

“…Furthermore, it was reported that the stationary phase showed good separation performance for polar compounds, including nucleosides and nucleic acid bases with high column efficiency and good stability. In addition, hydrophilic polymer coated silica has been extensively studied, such as polyvinyl alcohol (PVA) [6] and hydrogel [7] modified silica. Yang's group [8] prepared a PVA-coated silica stationary phase for hydrophilic interaction liquid chromatography by thermal immobilization, and it exhibited excellent separation of polar compounds.…”

“…Yang's group [8] prepared a PVA-coated silica stationary phase for hydrophilic interaction liquid chromatography by thermal immobilization, and it exhibited excellent separation of polar compounds. Furthermore, our group [7] prepared a double-layer hydrogel-functionalized silica material as stationary phase by combining physical coating and chemical coating for liquid chromatography. Interestingly, since the hydrogen bond between the stationary phase and the analyte changes at different temperatures in the column oven, the retention behavior changes, which indicated that the obtained new stationary phase showed characteristics of temperature response.…”

Preparation of spherical silica hydroxyl‐functionalized covalent organic polymer composites for mixed‐mode liquid chromatography

“…Compared with single-mode stationary phases, the mixed-mode stationary phases that possess multiple chromatographic ligands have attracted substantial attention owing to their superior selectivity and separation efficiency for complex mixtures of analytes [6][7][8]. Great efforts have been made in designing and fabricating advanced mixed-mode stationary phases [9][10][11][12]. In the last decade, many porous materials, such as metal-organic frameworks (MOFs) and covalent organic frameworks (COFs), have been praised as promising column-packing materials for chromatographic separation thanks to their distinctive structures and fascinating properties [13][14][15][16][17][18].…”