Simultaneous adsorption and fluorescent sensing of ampicillin based on a trimetallic metal-organic framework

Antibiotic residue is a growing concern for human health, and exploring a method for antibiotic detection is imperative Herein, a trimetallic metal-organic framework (NH2-MIL-53(Al)@Mo/Zn-MOF) with an adsorption effect was prepared by growing Mo/Zn-MOF on the surface of NH₂-MIL-53(Al) for simultaneous pre-concentration and detection of ampicillin (AMP). The NH₂-MIL-53(Al)@Mo/Zn-MOF showed a large specific surface area and stable crystal structure, which is conducive to improving the adsorption efficiency and detection sensitivity. The adsorption process of NH₂-MIL-53(Al)@Mo/Zn-MOF to AMP was simulated by a quasi-second-order kinetic model and Langmuir model. Moreover, a ratiometric fluorescent sensor was established based on fluorescence donors of NH₂-MIL-53(Al)@Mo/Zn-MOF and CdTe QDs@SiO₂ and a quencher of mitoxantrone (MIT). With the increasing concentration of AMP, the fluorescence of CdTe QDs@SiO₂ was gradually quenched by MIT through the inner filter effect (IFE) and photoinduced electron transfer (PET) process. At the same time, that of NH₂-MIL-53(Al)@Mo/Zn-MOF was maintained. With this strategy, the sensor achieved an ultra-sensitive detection of AMP with a low detection limit of 0.69 nM. Moreover, the constructed sensor exhibited satisfactory accuracy and reliability for AMP detection in food and environmental samples, which provides a new idea for developing integrated sensors for simultaneous adsorption and detection of antibiotics.