Surface-enhanced Raman scattering of flavonoids

The surface-enhanced Raman scattering (SERS) spectra of a group of flavonoids with related structures (quercetin, kaempferol, luteolin and apigenin) are reported here for the first time. It is demonstrated that the studied flavonoids undergo a chemical change on the Ag nanoparticles prepared by reduction with citrate used as a SERS substrate. Two labile chemical groups have been identified, one of them corresponding to the catechol-like moiety and another one corresponding to the C-ring, when a hydroxyl group is in position α with respect to the keto group. Copyright © 2006 John Wiley & Sons, Ltd.