Dual-emission 3D supramolecular framework hydrogel beads: highly selective detection of antibiotics and mechanism research

Abstract

Ratiometric fluorescent probes based on coordination polymers (CPs) have been widely applied in optical applications. Therefore, it is very important to develop a dual-emitting gel material based on coordination polymers for specific recognition of molecules. Cu-atda (H₂atda = 3,3′-(4-amino-1,2,4-triazol-3,5-diyl) dibenzoic acid) is synthesized with a porous structure and a large number of amino sites exposed on the surface, which can be regarded as a carrier for fluorescent molecules and well disperse in the SA hydrogel network. A dual-emission Eu³⁺ functionalized CP hydrogel bead (9A/Cu-atda@Eu³⁺/SA, 9A = 9-anthraldehyde and SA = sodium alginate) is successfully prepared, which presents ratiometric fluorescence detection of flumequine with a low detection limit (48 nM) and high selectivity. Furthermore, it also displays an excellent fluorescence quenching effect on nitrofuran antibiotics, exhibiting a dual functional performance. In addition, the fluorescence response mechanisms of flumequine and nitrofuran antibiotics are discussed in depth. As a portable material, visualization 9A/Cu-atda@Eu³⁺/SA beads provide an extensive and convenient application prospect for real-time monitoring of antibiotics in the water environment.