Ionic liquid/covalent organic framework/silica composite material: Green synthesis and chromatographic evaluation

Yuanfei Liu; Sunqi Shang; Wanjiao Wei; Yuefei Zhang; Wei Chen; Sheng Tang

doi:10.1016/j.aca.2023.341992

Ionic liquid/covalent organic framework/silica composite material: Green synthesis and chromatographic evaluation

Anal Chim Acta. 2023 Dec 1:1283:341992. doi: 10.1016/j.aca.2023.341992. Epub 2023 Nov 1.

Authors

Yuanfei Liu¹, Sunqi Shang¹, Wanjiao Wei¹, Yuefei Zhang¹, Wei Chen¹, Sheng Tang²

Affiliations

¹ School of Chemistry and Environmental Engineering, Hubei Key Laboratory of Novel Reactor and Green Chemical Technology, Key Laboratory of Green Chemical Process of Ministry of Education, Wuhan Institute of Technology, Wuhan, 430205, China.
² School of Chemistry and Environmental Engineering, Hubei Key Laboratory of Novel Reactor and Green Chemical Technology, Key Laboratory of Green Chemical Process of Ministry of Education, Wuhan Institute of Technology, Wuhan, 430205, China. Electronic address: stang@wit.edu.cn.

PMID: 37977797
DOI: 10.1016/j.aca.2023.341992

Abstract

Background: Due to their large surface area and distinctive adsorption affinity, covalent organic frameworks (COFs) appear to be good candidates as liquid chromatographic separation materials with good application prospect. The development of COF materials in chromatographic science is currently in an exploratory stage. Especially, the practicability of COF@silica composite materials as liquid chromatographic stationary phases needs further exploration. Reasonably integrating a functional component such as ionic liquid (IL) into the COF@silica composite materials may provide customized functionality to achieve the purpose of synthesizing multi-functional COF based stationary phases.

Results: In this study, an IL modified COF bonded silica composite material (IL-COF@SiO₂) was successfully synthesized by using an environmentally friendly deep eutectic solvent as the reaction medium instead of the frequently-used organic solvent. The synthesized IL-COF@SiO₂ composite material combines the excellent separation ability of COF and the excellent mass transfer function of spherical porous silica microsphere, and meanwhile, the introduction of IL endows COF@SiO₂ with preferable separation performance. The slurry-packed IL-COF@SiO₂ liquid chromatographic column could be applied to effectively separate hydrophobic and hydrophilic compounds with preferable separation selectivity and high column efficiency. By investigating the retention behavior and influencing factors, a mixed-mode retention mechanism was found. Multiple interaction forces endow the IL-COF@SiO₂ with a hydrophilic-hydrophobic balance performance, demonstrating a good application prospect as a versatile liquid chromatographic separation material.

Significance: In this study, a new strategy is proposed for greenly synthesizing a novel IL-COF@SiO₂ composite material under mild conditions, which expands the potential application of COF materials in chromatographic science. One particular point to note is that the reaction medium in each step of the preparation process is low toxic and degradable deep eutectic solvent, which conforms to the concept of green chemistry.

Keywords: Covalent organic framework; Deep eutectic solvent; Ionic liquid; Liquid chromatography; Stationary phase.