Abstract
Synthetic cannabinoids (SCs) represent the most rapidly proliferating class of new psychoactive substances, and their detection in urban wastewater is critical for drug situation monitoring. However, the low concentrations and complex matrix of wastewater pose significant challenges for sample pretreatment. Herein, three magnetic covalent organic framework composites (Fe₃O₄@COFs-1 to -3) with different functional groups were prepared
via
in situ growth of COF shells on Fe₃O₄ nanospheres. Systematic characterization revealed that Fe₃O₄@COFs-1 (chlorine-functionalized) exhibited the highest BET surface area (1194 m²/g), excellent crystallinity, superior thermal stability, and favorable hydrophilicity (water contact angle ~60°). Adsorption evaluation using nine SCs as targets and nine common drugs as controls demonstrated that Fe₃O₄@COFs-1 possessed the best comprehensive adsorption performance and selectivity. Under optimized conditions (methanol as binding solvent, pH=8, 40 min adsorption, 0.1% formic acid in acetonitrile as eluent, 30 min elution), the maximum adsorption capacity for 5F-CUMYL-PINACA reached 18.11 μg/mg, with an average of 16.45 μg/mg across nine SCs. The material retained over 65% adsorption efficiency after 5 reuse cycles. Coupled with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), the established method showed good linearity (1–150 μg/L, r² > 0.99), low detection limit (0.5 μg/L), and satisfactory precision (RSD < 15.6%). This work provides an efficient and convenient approach for the enrichment and determination of SCs in urban wastewater.