A bifunctional miniaturized sensor based on dual-luminescent europium metal-organic framework for sensitive ratiometric and visual detection of Sn4+ and amitraz

Developing a multifunctional sensor that can detect food-related multi-analytes is significant for food safety but remains challenging due to the difficulty of integrating multiple functions into one sensor. Herein, a dual-luminescent europium metal-organic framework (EuMOF) was elaborately synthesized through a simple self-assembly process, during which Eu 3+ coordinated with 2-hydroxyterephthalic acid (HTPA) and 1,10-phenanthroline that delivered strong characteristic fluorescence of HTPA and Eu 3+ . The resultant EuMOF exhibited good detection performance toward Sn 4+ and amitraz with different response behaviors. As for target Sn 4+ , the remarkably enhanced fluorescence from HTPA was observed and the fluorescence for Eu 3+ decreased significantly, which was attributed to the structural disintegration of EuMOF caused by Sn 4+ . Whereas, the presence of amitraz weakened both luminescence of HTPA and Eu 3+ owing to the synergistic function of inner filter effect and photoinduced electron transfer. Furthermore, an intelligent and miniature sensor that incorporated EuMOF-based test paper with color recognition application was exploited for portable visual analyzing Sn 4+ and amitraz in real samples, affording great possibilities for on-site monitoring of food hazards.