Core–Shell Metal–Organic Frameworks as the Stationary Phase for Hydrophilic Interaction Liquid Chromatography

Abstract

A strategy based on in situ growth of a metal–organic framework composite material was proposed by introducing a sodium dodecyl benzenesulfonate (SDBS) group to increase the electrostatic interaction between the MOF ligand and silica. In this work, mesoporous silica spheres were first functionalized with a zirconium­(IV)-based metal–organic framework material (MOF-808), which produced a core–shell particle (MOF-808@silica) as a hydrophilic interaction liquid chromatography (HILIC) stationary phase. The obtained material improves and enhances the selectivity and stability of the stationary phase in traditional MOF-based HILIC. A series of methods such as elemental analysis, scanning electron microscopy, Fourier-transform infrared spectroscopy, and Brunauer–Emmett–Teller were used to confirm that MOF-808 was successfully modified onto silica. The relative standard deviation (RSD) of the retention time for stability with 120 h of continuous elution was found to range from 0.2% to 0.6%, and the RSD of the repeatability for 10 replicates of continuous elution was found to range from 0.1% to 0.3%. Furthermore, the column batch-to-batch reproducibility of the retention time was reproducible with an RSD of less than 2.2% depending on the analyte. The composite materials were found to be superior to most reported MOF-based stationary phases in terms of separation performance for various polar compounds, preparative reproducibility, and chromatographic stability. In short, MOF-808@silica composite material expands and improves the use of MOF materials as stationary phases in hydrophilic chromatography, revealing a method to prepare a MOF@silica composite that shows good performance when used for chromatographic analysis.

Recent trends on the implementation of reticular materials in column‐centered separations

“…In situ growth of MOFs on silica particles has been carried out through the immobilization of sodium dodecyl benzenesulfonate, increasing the electrostatic interaction between the selected MOF precursors and the silica substrate [ 34 ]. Using this approach, MOF‐808 (Zr(IV)‐trimesic acid) was grown on mesoporous silica obtaining a stationary phase for hydrophilic interaction LC.…”

Hybrid Porous Crystalline Materials from Metal Organic Frameworks and Covalent Organic Frameworks

“…In Situ Interfacial Growth: In the past decades, seeded in situ growth has emerged as a powerful means to fabricate MOF-based composites by hybridizing MOFs with various functional materials, including polymers, [38] metal nanoparticles, [108] carbon nanotubes, [109] quantum dots, [110] and silica spheres. [111] This approach has been employed as a general strategy for the construction of MOF/COF hybrids. The first example was demonstrated by Zhang and coworkers in 2018.…”

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

“…In addition, Li's group [13] designed UiO-67 modified silica core-shell materials as stationary phase for liquid chromatography and the prepared UiO-67@SiO 2 column showed outstanding selectivity for separation of hydrophilic compounds, such as thioureas. Furthermore, our group prepared MOF-808@silica [14] core-shell materials by in situ growth MOF on silica surface with the help of sodium dodecyl benzenesulfonate. It was demonstrated that the obtained materials can be used as stationary phase for hydrophilic interaction liquid chromatography and showed excellent separation performance in terms of alkaloids and nucleosides.…”