Highly Sensitive Detection of Melamine Using a One-Step Sample Treatment Combined with a Portable Ag Nanostructure Array SERS Sensor

There is an urgent need for rapid and reliable methods able to detect melamine in animal feed. In this study, a quick, simple, and sensitive method for the determination of melamine content in animal feed was developed using surface-enhanced Raman spectroscopy on fabricated Ag nanorod (AgNR) array substrates with a one-step sample extraction procedure. The AgNR array substrates washed by HNO3 solvent (10(-7) M) and methanol and showed the good stability within 6 months. The Raman shift at Delta v = 682 cm(-1) was used as the characteristic melamine peak in the calculations. Sufficient linearity was obtained in the 2-200 mu g.g(-1) range (R-2 = 0.926). The limits of detection and quantification were 0.9 and 2 mu g.g(-1), respectively. The recovery rates were 89.7-93.3%, with coefficients of variation below 2.02%. The method showed good accuracy compared with the tradition GC-MS analysis. This new protocol only need 2 min to fininsh the detection which could be developed for rapid onsite screening of melamine contamination in quality control and market surveillance applications.