A Small-Molecule Fluorescent Probe for Rapid and Selective Detection of Carbamazepine in Aquatic Environments

Carbamazepine (CBZ), a representative pharmaceutical micropollutant, is frequently found in aquatic systems because of its broad application, strong chemical persistence, and limited elimination during conventional wastewater treatment. In this work, a small-molecule fluorescent probe was designed for the selective recognition of CBZ. The extended π-conjugated plane and heteroatom-containing sites of the probe were designed to match the fused aromatic framework and amide/carbonyl features of CBZ. This molecular-level complementarity may facilitate noncovalent probe-CBZ association and contribute to the observed fluorescence quenching response. Its sensing properties, stability, resistance to interference, biocompatibility, and fluorescence response mechanism were then comprehensively evaluated. The probe showed a CBZ concentration-dependent fluorescence quenching behavior within the range of 0-1000 μg/mL, and the limit of detection was calculated to be 2.351 μg/mL. Stable fluorescence emission was retained under pH 6-9, and the probe also exhibited favorable photostability. Zebrafish embryo experiments showed no obvious influence, indicating low biological toxicity and good environmental compatibility. Mechanistic investigations involving XPS, FTIR, DFT calculations, fluorescence lifetime analysis, Stern-Volmer analysis, and DLS collectively support a noncovalent probe-CBZ association process accompanied by electronic redistribution and changes in the association state. Taken together, the developed probe provides a preliminary fluorescence-based strategy for CBZ analysis in aqueous systems.