Adsorption of (S)–(+)–O-acetylmandelic acid on gold nanoparticle surfaces investigated by surface-enhanced Raman scattering

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 ∼1350 cm−1. Nearly identical spectral features to those of phenylacetic acid in conjunction with the disappearance of the CO stretching band at ∼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.