Synthesis and characterization of Au@Ag/Ce-UIO-66 nanocomposite for highly sensitive detection of sulfadiazine residue.

[Display omitted] • 1. We anchored the core–shell nanostructure of bimetallic gold core silver core on the surface of Ce-UIO-66 for the first time (Au@Ag), prepared Au@Ag/Ce-UIO-66 composite material. • 2. The substrate has excellent adsorption characteristics, reaching its maximum adsorption value within 10 min and achieving adsorption equilibrium within 30 min. • 3. The minimum detection limit for sulfadiazine can reach 2.5 μg/L, far below the minimum residue level specified by the European Union. • 4. Under certain acidic and alkaline conditions, the SERS spectrum of sulfadiazine remains unchanged, providing a new method for the detection of sulfadiazine in complex environments. • 5. Explored the adsorption and SERS enhancement mechanism between Au@Ag/Ce-UIO-66 and sulfadiazine. Antibiotic residue detection plays a key role in ensuring human health. However, rapid, reliable, and highly sensitive detection methods are still insufficient. To tackle this challenge, in this study, the Au@Ag/Ce-UIO-66, a nanocomposite material consisting of bimetallic gold core and silver shell (Au@Ag) introduced on the surface of Ce-UIO-66, was successfully synthesized. By meticulously regulating the exact concentration and volume of silver nitrate, we successfully generated an optimal matrix. This significantly enhanced the detection capability of the probe molecule CV to an impressive concentration of 10−9 M, with a remarkably low relative standard deviation of 7.54 %. The matrix exhibits excellent surface-enhanced Raman scattering (SERS) performance and stability, reaching adsorption equilibrium within 30 min. Moreover, employing this substrate enables the detection of sulfadiazine at concentrations as minimal as 2.5 μg/L, significantly surpassing the standards set by the European Union. Notably, the Raman spectral signal of sulfadiazine maintains stability across various pH conditions at a concentration of 10−5 M. Finally, the adsorption mechanism and enhancement mechanism between Au@Ag/Ce-UIO-66 and sulfadiazine were explored. [ABSTRACT FROM AUTHOR]