Adsorption of (S)-(+)-O-acetylmandelic acid on gold nanoparticle surfaces was examined by means of surface-enhanced Raman scattering. The adsorbate was presumed to bind to the surface via the carboxylate functional group due to the presence of symmetric stretching bands at similar to 1350 cm (1). Nearly identical spectral features to those of phenylacetic acid in conjunction with the disappearance of the C=O stretching band at similar to 1700 cm (1) were exhibited in the SERS spectra. These observations suggest scission of the carboxyl group into a benzyl radical intermediate on gold nanoparticle surfaces. (C) 2008 Published by Elsevier B.V.