Ionic liquid-functionalized covalent organic frameworks on the surface of silica for online solid-phase extraction

Area of Science:

• Materials Science
• Analytical Chemistry
• Separation Science

Background:

• Covalent organic frameworks (COFs) offer tunable properties for advanced material applications.
• Ionic liquid functionalization can enhance the selectivity and efficiency of extraction materials.
• Developing sensitive analytical methods for environmental contaminants like estrogens is crucial.

Purpose of the Study:

• To synthesize and characterize ionic liquid-grafted COFs on porous silica.
• To investigate the extraction mechanisms of various organic compounds using these novel materials.
• To establish a sensitive online analytical method for estrogen detection.

Main Methods:

• Synthesis of COF on porous silica using specific monomers.
• Grafting of ionic liquids onto the COF via click reaction.
• Construction of online solid-phase extraction-liquid chromatography systems.
• Investigation of extraction mechanisms including π-π, hydrogen-bond, and electrostatic interactions.

Main Results:

• The ionic liquid-functionalized COF demonstrated effective extraction of polycyclic aromatic hydrocarbons, bisphenols, diphenylalkanes, and benzoic acids.
• The developed online analytical method achieved a low detection limit (0.005 μg L⁻¹), wide linear range (0.017-10.0 μg L⁻¹), and high enrichment ratio (3635).
• Successful application to the detection of estrogens in actual samples with recoveries ranging from 70% to 129%.

Conclusions:

• Ionic liquid-functionalized COFs are promising sorbent materials for solid-phase extraction.
• The developed online SPE-LC method provides a sensitive and efficient approach for estrogen analysis.
• This technology has significant potential for environmental monitoring and sample analysis.