Melamine sensing in milk products by using surface enhanced Raman scattering.

Simple and rapid detection of trace amounts of melamine in milk products has been achieved with a portable sensor system based on surface-enhanced Raman scattering (SERS). The sensor system comprised high-performance gold nanofinger SERS sensor chips and a custom-built prototype portable Raman spectrometer. Compared to the FDA procedure and previously reported studies that were limited to laboratory settings, our sampling and analytical methods are simple (with one sampling step), less time-consuming, and cost-effective. We found the limit of detection (LOD) of the melamine is 120 parts per trillion (ppt) in water and 100 parts per billion (ppb) in infant formula, which are well below the FDA's tolerance level of 1 ppm in infant formula.