A ratiometric fluorescence sensor based on Eu3+@tetrafluorosuccinic acid functionalized UiO-67: Enhancing the detection performance of ofloxacin through pre-concentration effect

A novel of ratiometric fluorescence sensor Eu 3+ @UiO-67-TFSA with pre-concentration effect was fabricated by PSM. • The prepared Eu 3+ @UiO-67-TFSA exhibited high selectivity and sensitivity toward OFL. • The possible sensing mechanism of Eu 3+ @UiO-67-TFSA for OFL was systematically studied. • The Eu 3+ @UiO-67-TFSA paper sensor with smartphone allowed on-site visual rapid OFL detection. The excessive use of ofloxacin (OFL) has led to its persistent residues in water sources and animal-derived foods, posing a threat to human health. Therefore, it is urgent to develop fluorescent sensing materials capable of detecting ofloxacin in water environments and food matrices. Herein, a novel Eu 3+ @tetrafluorosuccinic acid-functionalized ratiometric fluorescent material Eu 3+ @UiO-67-TFSA was prepared by a two-step post-synthetic modification of UiO-67. In the concentration range of 1–15 μM, the Eu 3+ @UiO-67-TFSA had a limit of detection (LOD) of 0.42 μM for OFL, which was approximately 3.90 times lower than that of the non-fluorinated Eu 3+ @UiO-67-SA (LOD = 1.64 μM). The improved sensing performance could be attributed to the pre-concentration effect provided by the Eu 3+ @UiO-67-TFSA. The possible detection mechanism was systematically elucidated through relevant experiments and density functional theory (DFT) calculation. Moreover, the constructed smartphone-assisted visual sensing platform was successfully applied to detect OFL in actual food samples and real water environment samples. A novel ratiometric fluorescent sensor Eu 3+ @UiO-67-TFSA was synthesized through two-step PSM. The preparation of Eu 3+ @UiO-67-TFSA enabled effective detection of OFL via ratiometic fluorescence signals, with a detection limit as low as 0.42 μM, which was approximately 3.90 times lower than that of the non-fluorinated Eu 3+ @UiO-67-SA. The improved sensing performance could be attributed to the pre-concentration effect provided by the as-obtained Eu 3+ @UiO-67-TFSA. Furthermore, the fluorescent test strips based on Eu 3+ @UiO-67-SA was combined with smartphone to realized on-site, visual and rapid detection of OFL. Download: Download high-res image (286KB) Download: Download full-size image