One-step detection of melamine in milk by hollow gold chip based on surface-enhanced Raman scattering

A hollow gold (HG) chip with high surface-enhanced Raman scattering (SERS) capability was fabricated and used to monitor the adulteration of milk with melamine. This chip was fabricated with self-assembled hollow gold nanospheres (HGNs) on glass wafers through electrostatic interaction. There are two important advantages for the use of this HG chip as a detection platform. First, HGNs show a strong SERS enhancement from individual particles due to their capability to localize the electromagnetic fields around the pinholes in hollow shells. Second, the HG chip improves the limit of detection through the enrichment effect. The characteristic SERS peak of melamine was used to distinguish it from other kinds of proteins or amino acids, and its intensity was used to monitor the percentage of melamine in milk. With its simple detection procedure (no pretreatment or separation steps), decreased processing time and low detection limit, this HG chip shows a strong potential for broad applications in melamine detection from real samples.