Deciphering the Relationship between the Ordered Pore Structure and Solid-Phase Microextraction Behavior of Covalent Organic Frameworks for Phenols

Abstract

The extraction performance of materials is highly related to their physical structure. However, the range degrees of ordered pore structure of covalent organic frameworks (COFs) on their extraction performance are still puzzling. To look insight into this, a series of COFs with different degrees of ordered pore structures were prepared at room temperature by varying reaction time and their extraction efficiencies toward phenolic compounds were investigated. The experimental results suggested that the COF with short range ordered pore structure exhibited a higher affinity for phenolic compounds along with a larger enrichment factor, while the COF with long range ordered pore structure showed faster extraction kinetics. The interaction mechanism investigation revealed that the density of available sites is responsible for the difference. Taking COF-OMe-0.5 h as solid-phase microextraction fiber coating, a highly efficient and sensitive quantitative analysis method for phenolic compounds was established by combining it with gas chromatograph-mass spectrometer. The established method had high enrichment factors (7192-29440), wide linear ranges (2-10000 ng L-1), and low detection limits (0.23-0.85 ng L-1). This study provides a conceptual guide to construct desirable COFs with controlled pore structures for specific applications.

Keywords: Covalent organic frameworks, Ordered pore structure, Solid phase microextraction, Phenolic compounds