Smartphone-Integrated Ratiometric Sensor Based on a Sm(III)-MOF for Dual-Functional Detection of Vitamin B ₂ and Levofloxacin

Vitamin B 2 (VB 2 ) is directly involved in energy metabolism and cellular functions, playing a crucial role in maintaining human health, while residual levofloxacin (LVX) in food and environmental samples poses a potential risk to human health. Therefore, the development of sensors for efficiently detecting both VB 2 and LVX holds significant importance. Herein, a 2D Sm-MOF based on mixed ligands was hydrothermally prepared for ratiometric detection of VB 2 and LVX, {[Sm 2 (2,6-NDS)(3,4-pydc) 2 (H 2 O) 3 ]·2H 2 O} n ( Sm-MOF, where 2,6-NDS 2– = 2,6-naphthalenedisulfonate, 3,4-pydc 2– = 3,4-pyridinedicarboxylate). Due to the inherent emission of VB 2 and LVX, the on–off ratiometric sensing strategy based on Sm-MOF has been established. The Sm-MOF sensor displays favorable selectivity, anti-interference ability, and reusability toward ratiometric sensing of VB 2 and LVX in aqueous solution. Their corresponding detection limits reach 0.43 and 0.34 μM, respectively. Notably, a smartphone-integrated RGB method was explored for visual detection of VB 2 and LVX due to obvious color changes. The developed ratiometric sensing and RGB methods were also successfully utilized to detect VB 2 and LVX in various actual samples with excellent recovery rates from 96.4% to 105.2%. This Sm-MOF sensor offers a reliable strategy for VB 2 and LVX detection in food and environmental safety.