Development of jellyfish-like ZnO@Ag substrate for sensitive SERS detection of melamine in milk

Abstract

Melamine has received enormous attention because of being illegally adulterated into milk, posing potential threats to human health. It is vital for developing sensitive analytical methods for detecting melamine in milk at the lowest possible concentration. In this context, we proposed a highly sensitive surface-enhanced Raman scattering (SERS) substrate based on hybridization of jellyfish-like zinc oxide microparticles and silver nanoparticles (JF ZnO@Ag) for detecting melamine in milk. The JF ZnO with a rough surface facilitates the deposition of Ag nanoparticles and adsorbing analytes, providing the abundant “hot spots” for the electromagnetic enhancement and the suitable charge transfer path to induce the chemical enhancement. Using the rhodamine 6G (R6G) as the Raman probe, the enhancement factor is as high as 7.58 × 106. As a real application, the substrate was successfully utilized in the detection of melamine in milk. The limit of detection (LOD) was down to 0.098 ppm, which is lower than the safety limit in the USA (2.5 ppm). The results manifest that the proposed substrate is an effective strategy to be applied as an analytical platform for the efficient detection of melamine in milk.