Adhesive-free fabrication of covalent organic polymer aerogel coatings for solid-phase microextraction of phenolic compounds

Covalent organic polymer (COP) aerogels, with their hierarchical porous architecture enabling rapid mass transfer and exposing abundant accessible binding sites, hold significant potential as advanced extraction materials for sample pretreatment. Although extensive efforts have been devoted to developing COP aerogels, their direct application as solid-phase microextraction (SPME) coating materials remains unexplored.

This study introduces a rapid, straightforward, and adhesive-free method for synthesizing COP aerogel-based SPME coatings. Utilizing capillary tubes as confined growth molds, the COP precursor rapidly gels and firmly adheres to the surface of stainless steel wires, forming a monolithic coating. The coating thickness can be customized by simply employing capillary tubes with different internal diameters. When coupled with gas chromatography-mass spectrometry, a highly sensitive method for phenolic compound analysis was developed. The developed method exhibits a broad linear range (2.0-10000 ng L^-1; R² > 0.9911), low detection limits (0.13-0.58 ng L^-1), and high enrichment factors (4957-22037). Furthermore, the practical applicability was validated through the successful quantification of trace phenolic compounds in grapes, pears and apples, achieving satisfactory recoveries of 89.2-109% with relative standard deviations of 0.35-11.1%.

This study provides a rapid and straightforward approach to synthesizing customizable COP aerogel-based SPME coatings, providing a scale pathway to high-performance extraction media. The established analytical method enables ultrasensitive quantification of trace phenolic contaminants in real fruit matrices, offering a reliable analytical methodology for trace contaminant analysis in food and environmental samples.