Adsorption of the anthraquinone drug parietin on silver nanoparticles: A SERS and fluorescence study

The vibrational characterization of the anthraquinone pigment and drug parietin was carried out by means of infrared spectroscopy, Raman and Surface-enhanced Raman scattering (SERS) at different laser excitation lines. The vibrational spectra obtained experimentally were analysed using DFT calculations at the B3LYP/6-31+G** level. The SERS technique was very useful in the vibrational study of parietin, and was proven to be a highly sensitive technique for the detection of low concentrations of the drug. The silver nanoparticles used as SERS substrates were prepared by reduction with hydroxylamine hydrochloride. The adsorption of parietin on the nanoparticles at different surface coverage leaded to the calculation the limit of detection (LOD) and the adsorption constant (Kad) of parietin on the SERS substrate.