Lamellar Homogeneous COF Film Loaded on Ultrathin PDMS for Simultaneous and Exceptional Solid Phase Microextraction of Antibiotics

Green solid phase microextraction (SPME) is a promising technique for effectively enriching high-profile and trace antibiotics, while its limited extraction phase volume and adsorbent load restrict the extraction efficiency. It remains a challenge to develop a rationally designed device with a high proportion of adsorbents for increased performance. Herein, using 3,8-diamino-6-phenylphenanthridine (DPP) and 1,3,5-triformylphloroglucinol (TP) as monomers, a β-ketoenamine-linked covalent organic framework membrane (TPDPP) was fabricated via interface assembly. TPDPP was further loaded on ultrathin polydimethylsiloxane (PDMS) using solvent evaporation, resulting in a high proportion of TPDPP functional components in the hybrid membrane (TPDPP@PDMS). This approach was highly feasible for the batch preparation of TPDPP@PDMS with a lamellar homogeneous structure and controllable layers. These TPDPP@PDMS membranes demonstrated outstanding enrichment performance for common antibiotics, particularly sulfonamide antibiotics, with extraction efficiencies 7.73–12.7 times higher than those of TPDPP fibers and 3.91–93.9 times higher than those of commercial fibers. The TPDPP@PDMS membranes reproducibly performed simultaneous SPME in a variety of environmental water samples, simplifying the pretreatment process and saving time. By integration of the membranes with liquid chromatography–tandem mass spectrometry, an ultrasensitive method was established to achieve parallel extraction and highly efficient antibiotic quantification, demonstrating great potential for environmental pollutant monitoring.