Research on the surface-enhanced Raman spectrum of sodium sulfide nonahydrate and its application in monosodium glutamate detecting

The surface-enhanced Raman spectrum of sodium sulfide was studied and the structure vibration information was obtained. The Raman characteristic peak at 472 cm^-1 was selected to evaluate enhanced effects. Gold colloid was used as active substrate, the relationship between gold nanoparticle size and enhanced efficiency was analysised and the optimum size for SERS is 97 nm. The surface enhanced Raman scattering spectra of sodium sulfide at different concentrations were also presented. The results indicated that SERS spectra of sodium sulfide can be found even the concentration reach 10^-6 g·mL^-1. The performance of active substrate is related with the ratio of sample and gold colloid. In the real situation, 1 g monosodium glutamate was added to 10mL sodium sulfide solution with different concentration and then SERS spectra of these samples were collected respectively. The lever of qualitative detection can reach 10mg·kg^-1. And due to the simple procedure in sample preparation, this method is of great potential in on-line qualitative detection.