Construction of a Nitrogen-Doped Carbon Quantum Dot Fluorescent Molecularly Imprinted Sensor for Ultra-Sensitive Detection of Sulfadiazine in Pork Samples

In the realm of food safety, the accumulation and potential health risks posed by persistent residues of broad-spectrum antimicrobials, which degrade slowly in the environment, have prompted the urgent development of efficient and sensitive detection methods. Addressing this challenge, nitrogen-doped carbon quantum dots (N-CQDs) were synthesized through a high-temperature hydrothermal method using citric acid and urea as sources. Utilizing these N-CQDs, a sensor incorporating molecularly imprinted polymers was developed through a sol–gel process with sulfadiazine (SDZ) as the template molecule. This involved using 3-aminopropyltriethoxysilane and tetraethyl orthosilicate as the monomer and cross-linker, respectively. The resulting sensor exhibited a linear detection range of 0 to 30 µmol/L and a notably low detection limit of 0.04 µmol/L. Further testing on actual pork samples revealed recovery rates between 95.10 and 108.30% and a relative standard deviation below 2.0%, emphasizing its high sensitivity and selectivity. This advancement not only enhances SDZ detection capabilities, but also paves the way for broader applications in food safety monitoring, setting a solid foundation for future developments in sensor technology.