Studies on adsorption of carnosine on silver nanoparticles by SERS

The surface-enhanced Raman scattering (SERS) studies of l-carnosine was carried out in aqueous silver sol at pH ∼ 9 and compared with the normal Raman spectrum of the molecule. The experimentally observed Raman bands were assigned based on the results of DFT calculations. Significant changes in the relative intensity are seen in the SERS spectrum when compared to the normal Raman spectrum. The studies suggest that the interaction of carnosine is primarily through the carboxylate group with the imidazole ring in an upright position with respect to the silver surface and the alanine moiety assuming a parallel orientation with the surface where NH2 group is close to the silver surface.