STUDY OF DETECTION OF MELAMINE VIA SURFACE-ENHANCED RAMAN SCATTERING METHOD BASED ON SILVER NANOPARTICLES

Abstract

Silver nanoparticles (Ag NPs) were synthesized and characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and absorption spectroscopy. Using Debye-Scherrer’s formula and the result of the XRD spectrum, the size of the Ag NPs was estimated at approximately 8 nm. The fabricated silver nanoparticles were used to perform surface-enhanced Raman scattering (SERS) for detecting melamine. The SERS mechanism was discussed and indicated that electromagnetic enhancement played an important role; the contribution of chemical enhancement could be ignored due to the out-of-charge transfer resonance between Ag NPs surface and melamine molecules. The SERS activity of Ag NPs substrate in probing melamine was examined with a variety of concentrations ranging from 1.5×10^-3 to 10^-7 M. The SERS spectra of melamine molecules presented a good sensitivity with a limit of detection of 10^-7 M, corresponding to an enhancement factor (EF) of 2×10⁵. The results show quite high sensitivity for probing melamine.