Functionalized infinite coordination polymers: A ratiometric fluorescence sensor for tetracycline detection

Sensitivity, reliability, and practicality were crucial indicators for evaluating analytical methods. Therefore, a ratiometric fluorescence sensor based on infinite coordination polymers (ICP) was prepared, exhibiting high selectivity and sensitivity for tetracycline (TC) detection. This sensor took ICP as the matrix; UiO-66-NH₂ was encapsulated into it through simple synthesis, and the resulting composite was designated as UiO@Eu-ICP. This functionalization strategy endowed UiO@Eu-ICP with dual-emission characteristics simultaneously. Throughout the TC detection process, the blue fluorescence (λ_em = 424 nm) of UiO-66-NH₂ within UiO@Eu-ICP was quenched. Concurrently, the β-diketone structure of TC displaced water molecules coordinated to Eu³⁺ via strong coordination, sensitizing UiO@Eu-ICP to emit red fluorescence (λ_em = 617 nm). This ratiometric sensor exhibited self-calibration property and effectively reduced background interference. Consequently, using UiO@Eu-ICP as a sensor enabled highly sensitive detection of TC, with a low detection limit (17.6 nM) and rapid response time (within 10 s), demonstrating great potential for applications in food testing and related fields.