A SERS sensor of g-C3N4/Au@Ag thin film for detecting nitrofurantoin residues in honey

Abstract

Detecting antibiotic residues in food is a critical challenge for food safety assurance. This study developed a surface-enhanced Raman scattering (SERS) sensor based on two-dimensional graphitic carbon nitride (g-C₃N₄) loaded with Au@Ag core-shell nanostructures (g-C₃N₄/Au@Ag) for detecting nitrofurantoin (NFT) residues in honey. The g-C₃N₄/Au@Ag thin film was fabricated by sequentially depositing g-C₃N₄ nanosheets, Au nanoparticles, and Ag nanoparticles onto a stainless steel substrate via an electrochemical deposition method. This SERS sensor could synergistically amplify SERS signals by combining the localized surface plasmon resonance (LSPR) from the Au@Ag nanostructures with the charge transfer between the g-C₃N₄ semiconductor and Au@Ag nanostructures. The optimized SERS sensor achieved an exceptional SERS enhancement factor of 3.8×10⁶ for NFT in aqueous solutions, with a limit of detection (LOD) of 0.72 nM. Moreover, this SERS sensor could also recognize NFT residues in honey matrices at an LOD of 5 nM. These results provide a novel strategy for the highly sensitive detection of antibiotic residues in food safety monitoring, highlighting its potential for rapid screening of NFT residues in food.