Highly Sensitive and Flexible GFF/Au/AgNPs SERS Substrate and Its Application for Rapid Hazardous Residues Detection on Food

In this work, we have developed a highly sensitive surface enhanced Raman scattering (SERS) substrate consisting of gold (Au) and silver (Ag) nanoparticles (NPs) loaded on glass fiber filter paper (GFF) by a two-step process of magnetron sputtering and sessile drop method. To test the SERS properties of the substrate, crystal violet (CV) was selected as the Raman probes. The influence of the amounts of NPs on the SERS signals was studied using field-emission scanning electron microscopy and theoretical methods. It is demonstrated that the hybrid structure of optimal GFF/Au/AgNPs has a much stronger SERS enhancement than that of GFF substrate coated only with AuNPs, which can provide a SERS enhancement factor (EF) of 3.52 × 10 8 , and the limit of detection is down to 10 −14  M for CV. Moreover, the Raman signal of the CV on the GFF/Au/Ag substrate presented good homogeneity, reproducibility and stability, also reproduce the SERS spectra after 15 days. Furthermore, the GFF/Au/AgNPs substrate was applied for the rapid on-site testing and identification of malachite green (MG) residual on contaminated fish scale, and the limit of detection was approximately 10 −7  M. Flexible GFF substrate with Au/Ag bimetallic hybrid structure has great potential in rapid sampling of hazardous ingredients on real samples and in SERS applications.