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.