Gold Nanoparticle Response to Nitro-Compounds Probed by Cavity Ring-Down Spectroscopy
A C. Pipino, Vitalii I. Silin
The optical response of Au nanoparticles to adsorption of NO2, SO2, C6H5NO2, and 2,4-dinitrotoluene (DNT) is probed using the cavity ring-down technique. A uniquely sensitive response, which appears characteristic of the -NO2 group, is observed for the surface plasmon resonance (SPR) of an approximately Gaussian distribution of Au nanoparticles having a mean diameter of 4.5 nm. Detection limits of 1.2 nmol/L, 7.6 nmol/L, and 0.17 nmol/L, are estimated for NO2, C6H5NO2, and DNT, respectively, while SO2 shows no response.