A highly sensitive EC-SERS sensor of PANI/RGO/Ag/Cu film for doubly detecting glyphosate residues in fresh fruit.

Glyphosate (Gly) residues in agricultural products have a serious health risk, so it is urgent to seek a sensitive and convenient method for recognizing Gly residues in food. In this study, we proposed an electrochemical surface-enhanced Raman spectroscopy (EC-SERS) sensor of polyaniline/reduced graphene oxide/Ag/Cu (PANI/RGO/Ag/Cu) film to detect Gly residues. The EC-SERS sensor of PANI/RGO/Ag/Cu film had a large specific surface area, which could increase the binding sites of cu2+/Gly clathrates for boosting specifically its SERS signal. Moreover, Ag/Cu nanoparticles on the surface of film could effectively increase the differential pulse voltammetry signal and SERS signal of Gly molecules. The limit of detection of EC-SERS sensor to Gly could reach 1.9 nM. In addition, the EC-SERS sensor we prepared could also sensitively identify Gly residues on fresh fruit peels. The PANI/RGO/Ag/Cu film we proposed in this paper has great potential for selective and accuracy detecting Gly residues in agricultural products.