Europium Metal Organic Framework Modified Polydopamine@MXene Molecularly Imprinted Electrochemical Sensor for Detection of Sulfadimethoxine

Sulfadimethoxine (SDM) is a broad-spectrum sulfonamide bacteriostatic agent widely used in aquaculture. However, improper usage leading to excessive residues poses potential threats to food safety and human health. Thus, developing rapid and sensitive detection methods for monitoring SDM in food is of great importance. In this study, an Eu-MOF-PDA@MXene composite material was prepared via an in-situ synthesis method. By modifying the surface layers with polydopamine (PDA) and europium metal organic framework (Eu-MOF), the oxidation and self-stacking of MXene were prevented, significantly enhancing its conductivity and structural stability. Based on this composite material and combined with molecular imprinting technique, a highly specific and sensitive MXene-based molecularly imprinted electrochemical sensor was constructed for rapid quantitative detection of SDM. Under the optimal detection conditions, the sensor exhibited an ultra-low detection limit (2.2 ng/L), a wide linear detection range (0.05–500 μg/L), as well as good selectivity, stability, and reproducibility. The sensor was successfully applied to detection of SDM in grass carp samples, with a detection time of only 3 min and spiked recoveries of 89.5%–91.1%, demonstrating good application potential. This study provided a rapid and simple method for determination of SDM residues in food, offering important technical guidance for food safety monitoring.