Detection Enhancement of One Multifunctional Cd-Metal-Organic Framework toward Tetracycline Antibiotics by Simply Mixing Eu3+ in Suspension

It is necessary to find more simple methods to improve the detection selectivity and sensitivity of antibiotics. Herein, we constructed a novel three-dimensional (3D) Cd-MOF LCU-117 assembled from p-terphenyl-4,2,5,4'-tetracarboxylic acid, which showed a special 3D helical structure with carboxylic acid ligands and nitrogen-containing ligands crossing each other vertically. Luminescence measurements indicated that LCU-117 has high selectivity and sensitivity toward Eu3+ through the ratiometric effect. Meanwhile, this complex itself could detect antibiotics oxytetracycline (OTC) through the turn-off mechanism. When Eu3+ was added in suspensions of LCU-117 (noted as Eu3+@LCU-117), the detection toward OTC was enhanced significantly and visually. The sensing mechanism was investigated in detail by various measurements and theoretical calculations. LCU-117 has a good effect on the logic gate, potential fingerprint detection, and mixed-matrix membranes (MMMs). The practical application for monitoring OTC in water samples also provided a satisfactory result.

Automated summary

A novel three-dimensional Cd-MOF LCU-117 was constructed, which exhibited a unique helical structure and had high selectivity and sensitivity towards Eu3+ ions. LCU-117 could detect antibiotic oxytetracycline (OTC) through the turn-off mechanism, and the detection capability was significantly enhanced when Eu3+ was added. LCU-117 showed promising applications in logic gates, potential fingerprint detection, and mixed-matrix membranes (MMMs), and provided satisfactory results in monitoring OTC in water samples.