Embedding sulfonic acid group into covalent organic frameworks for enhancing extraction of endocrine-disrupting...

Bisphenols (BPs) as widely used endocrine-disrupting chemicals can seriously endanger human health. A covalent organic framework (COF) skeleton functionalized with sulfonic acid groups (DT-BD_(0.25)-SO₃H_(0.75)-COF) was designed and constructed through Schiff base reaction. The DT-BD_(0.25)-SO₃H_(0.75)-COF proved to be a brilliant adsorbent, displaying enhanced BPs extraction capability (bisphenol S, bisphenol A, bisphenol F, and bisphenol B). Coupling DT-BD_(0.25)-SO₃H_(0.75)-COF based solid-phase extraction with high performance liquid chromatography-mass spectrometry, we developed a reliable method for sensitive detection of BPs in low-fat milk, skim milk and whole milk samples, realizing excellent analytical performance with low detection limits of 0.06-0.17 ng mL^-1, high spiked recovery of 85.7-104%, and satisfactory relative standard deviation of 3.5-6.4%. This work not only highlights DT-BD_(0.25)-SO₃H_(0.75)-COF as a highly effective adsorbent for effectively enriching BPs, but also introduces a novel strategy for COF functionalization‌, paving the way for broader applications in pollutant monitor and removal.