Eu-functionalized hydrogen-bonded organic frameworks as a ratiometric fluorescent sensor for highly sensitive...

Zearalenone (ZEA) is a toxic compound produced by fungal metabolism, which possesses mutagenicity, teratogenicity, carcinogenicity, nephrotoxicity, immunotoxicity, and genotoxicity, posing a serious potential threat to human and animal health. Therefore, establishing a rapid and accurate detection method for ZEA residues in food is of great significance for ensuring food safety. In this work, a hydrogen-bonded organic framework (HOF) was synthesized via self-assembly using melamine and trimesic acid as building units, followed by doping with rare earth metal europium ions (Eu³⁺) to successfully prepare a europium-functionalized HOF fluorescent sensor (Eu@HOF-TMA) with excellent stability. Eu@HOF-TMA exhibited a specific ratiometric fluorescent response to ZEA. As the ZEA concentration increased, the fluorescent color of the sensor gradually changed from red to blue. Eu@HOF-TMA exhibited a limit of detection as low as 0.57 µM for ZEA, with a response time of less than 30 s, which represents the fastest-response sensor for ZEA reported to date. Moreover, Eu@HOF-TMA could realize quantitative detection of ZEA in corn flour and drinking water with good recovery rates, indicating its excellent potential for practical application. Furthermore, relying on the significant change in fluorescent color of Eu@HOF-TMA after interaction with ZEA, a portable and instrument-free visual detection method for ZEA was constructed using a smartphone RGB color recognition software. Consequently, this work successfully prepared an Eu-HOF ratiometric fluorescent sensor, which provides a new strategy for the sensitive, rapid, and portable detection of ZEA and can be effectively applied to the analysis of ZEA residues in real food samples.