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

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.