Fabricating organic molecular cage-based covalent organic framework for efficient adsorption of endocrine disruptive phenolic chemicals.

The effective extraction and sensitive detection of endocrine disruptive phenolic chemicals (EDPCs) in food matrices is of great importance for ensuring human health. This study develops a porous organic cage-based covalent organic framework (Cage-COF) as an advanced adsorptive material for solid-phase extraction (SPE) of EDPCs from milk samples. Interconnected 3D porous structure, large surface area (199 m2 g-1), electron-rich O, N heteroatoms and OH moieties endow Cage-COF with significantly enhanced active adsorption sites, leading to a highly effective affinity towards EDPCs. Theoretical calculation and control experiments clarified the interaction mechanism of pore filling, H bonds and π-π interaction between Cage-COF and EDPCs. A sensitive method for the quantification of four typical EDPCs at trace levels in whole milk and skim milk was established by coupling Cage-COF-based SPE and high performance liquid chromatography tandem mass spectrometry. The limits of detection for the EDPCs were between 0.01 and 0.06 ng mL-1, lower than that of most reported methods. Spiked recovery study gave the satisfactory recovery of 85% -115% and low relative standard deviations of 2.3% -9.0%. The distinguished adsorption performance of cage-based COFs unlocking their considerable untapped application potential in adsorption and separation.