Facile fabrication of three-dimensional gold nanodendrites decorated by silver nanoparticles as hybrid SERS-active substrate for the detection of food contaminants

Abstract

Applicable surface enhanced Raman scattering (SERS) active substrate require not only high enhancement factor (EF), but also excellent reproducibility and facile fabrication process. Although some colloidal SERS substrates have advantages of high EF, random assembly causing the unstable signal remains a challenge. This study presented a simple, effective and reproducible SERS substrate for sensitive detection of melamine and thiram in food samples. A three-dimensional gold nanodendrites (AuNDs) decorated by silver nanoparticles (AgNPs) via electrodeposition has been synthesized as hybrid SERS-active substrate. The synthesis conditions were optimized with voltage power of −1.5 V and deposition time of 300 s, consequently the gold nanodendrites were obtained. The developed AgNPs decorated AuNDs (Ag-AuNDs) substrate showed excellent Raman enhancement effect because of high local electromagnetic (EM) field enhancement. Under the optimal synthesis condition, the SERS substrate was utilized for quantitative detection of melamine and thiram, and the linear relationship were in the range of 0.01–5 mg/L for melamine and 0.12–24 mg/L for thiram. The limit of detection were 7.38 μg/L and 86.1 μg/L for melamine and thiram, respectively. Finally, the substrate was successfully applied to detect melamine in milk and thiram in apple juice, indicating that Ag-AuNDs substrate could be a promising SERS detection platform for food safety assurance.