Arrays of ZnO nanorods decorated with Au nanoparticles as surface-enhanced Raman scattering substrates for rapid detection of trace melamine

In this paper, as a new, highly sensitive and uniform hybrid surface-enhanced Raman scattering (SERS) substrate, arrays of ZnO nanorods (ZnO-NRs) decorated with Au nanoparticles (Au-NPs) have been prepared. This hybrid substrate manifests high SERS sensitivity to melamine and a detection limit as low as 1.0×10−10 M (1.26 µg L−1). A maximum enhancement factor of 1.0×109 can be obtained with the ZnO NF–Au (sample 2) film. Au-NPs gaps in the array can create lots of SERS “hot spots” that mainly contribute to the high SERS sensitivity. Moreover, the supporting chemical enhancement effect of ZnO-NRs and the better enrichment effect ascribed to the large surface area of the substrate also help to achieve a lower detection limit. The promising advantages of easy sample pretreatment, short detection time and low cost makes the arrays of ZnO-NRs decorated with Au-NPs substrate a potential detection tool in the field of food safety.