Au Nanoparticle/Graphene Oxide Composites Deposited on Au Nanorod Arrays as Substrates for Surface-Enhanced Raman Scattering Sensing

In this study, the objective was to develop Au nanorod arrays (AuNRAs) using two-dimensional (2D) graphene oxide (GO)-supported Au nanoparticles (AuNPs). Graphene oxide (GO) and AuNPs in different ratios were prepared, and the coupling performances for AuNRAs-GO/AuNPs were studied to optimize the AuNRAs-GO/AuNP substrate using 1,2-bis­(4-pyridyl)­ethylene (BPE). To further prove the Raman performance of AuNRAs-GO/AuNPs, Raman molecular BPE was used to assess the uniformity of Raman signaling across the substrate. The addition of GO/AuNPs endows AuNRAs with universally high adsorption of analytes and the electromagnetic mechanism from the multidimensional couplings of AuNRAs-GO/AuNPs enhances Raman performance; therefore, the AuNRAs-GO/AuNP preparation achieves sensitivity and repeatability. The optimized substrate was then used to detect melamine. Ultrasensitive detection of melamine reached a limit of detection of 10–9 M. To demonstrate the application potential of AuNPs/GO/AuNRAs, melamine was detected in liquid milk and its limit of detection was determined to be 1 ppm, which meets the maximum limit for the melamine content in infant milk as proposed by the World Health Organization, thus revealing the application potential of our method.