Magnetic MON@COF composites for efficient detection of NSAIDs from water

The presence of residual non-steroidal anti-inflammatory drugs (NSAIDs) in environmental water bodies has garnered increasing concern. In this study, two magnetic microporous organic networks (MONs) were synthesized by integrating them with imine-linked covalent organic frameworks (COFs), resulting in two novel magnetic MON@COF composites (MMON-Br@COF and MMON-I@COF) for the detection of NSAIDs in aquatic environments. The adsorption performance of these composites toward five commonly used NSAIDs was evaluated using high-performance liquid chromatography (HPLC). The results indicated that the adsorption process followed pseudo-second-order kinetics and the Freundlich isotherm model. Notably, MMON-Br@COF exhibited an adsorption capacity of up to 461.60 mg g^-1 for diclofenac sodium (DS). The adsorption mechanism involved π-π stacking, hydrogen bonding, and electrostatic interactions. The synergistic effect between the MON and COF components contributed to the efficient capture of NSAIDs. Thermodynamic analysis confirmed the spontaneous nature of the adsorption process. A new method for detecting NSAIDs by MSPE-HPLC was established based on MMON-Br@COF. In complex aqueous matrices, the method achieved a recovery rate exceeding 87.12 %, a low detection limit (0.045-0.110 μg l^-1), and excellent linearity (0.10-500 μg l^-1). This study presented a promising approach for the effective adsorption, detection, and removal of NSAIDs in water environments.