A Novel Rare Earth and Covalent Organic Framework Composite for Rapid and Highly Sensitive Electrochemical Analysis of Sulfadiazine in Fish Muscle

The misuse of sulfadiazine (SFZ) has led to great hazard to the environment and human safety; therefore, a simple, rapid, and sensitive method to detect sulfadiazine is urgently needed. Herein, we report a simple fabrication method for rare earth vanadate samarium (SmV)-doped covalent organic framework COFTDBA-TTL nanocomposites (SmV/COFTDBA-TTL), which were used to construct a sulfadiazine (SFZ) electrochemical sensor. The synergistic effect arising from the combination of SmV and COFTDBA-TTL accelerates the charge transfer kinetics, along with the creation of more surface-active sites that benefit effective detection. Compared with other electrochemical sensors, this electrochemical sensor exhibits low detection limit (2.40 nM), wide linear range (7.32–12.0 μM), good reproducibility (RSD = 0.823%), and stability (RSD = 3.60%). It provides a novel method and theoretical basis for the application of rare earth COF-based electrochemical sensors to detect environmentally destructive pollutants.