A novel reversible-responsive ratiometric fluorometry based on an anthracene-based imidazolium ionic liquid and Eu3+-based lanthanide coordination polymers for selective sensing tetracycline in foods and waters.

Detecting tetracyclines' (TC) residues is of great significance for evaluating the food and environmental safety. Herein, we pioneered a reversible-responsive ratiometric fluorometry by integrating the red fluorescence of Eu3+/GMP lanthanide coordination polymers (Eu3+/GMP LCPs) with the blue fluorescence of an anthracene-based imidazolium ionic liquid (ABIIL). In the presence of TC, the fluorescence of ABIIL was quenched by TC via the inner-filter effect and photoinduced electron-transfer process, but that of Eu3+/GMP LCPs was enhanced owing to the antenna effect between Eu3+ and TC. Based on the reversible variations of the fluorescence signals, a fluorescent assay based on ABIIL-Eu3+/GMP LCPs was engineered to detect TC with satisfactory sensitivity and selectivity. A good linearity for TC was acquired from 0 to 50 μM with the detection limit of 3.0 nM and the significant color changes. Therefore, the assay was a promising approach for the visual detection of TC in complex media.