Hydroxylamine reduced silver colloid for naphthalene and phenanthrene detection using surface-enhanced Raman spectroscopy

Hydroxylamine reduced silver colloid was used as a surface enhanced Raman scattering (SERS) substrate for the detection of trace-level polyaromatic hydrocarbons (PAHs). The colloidal particles were predominantly spherical in shape and the size of the particles was around 50 nm with a wavelength of maximum absorption at 420 nm. The silver nanoparticles had impressive enhancement of the sensing signal using SERS. Raman signals of an aqueous solution of naphthalene and phenanthrene were obtained for concentrations of 10−12 M and 10−10 M respectively. The SERS intensity decreases linearly with concentration allowing quantitative analyses of the PAHs in ethanol and aqueous solutions; with good linear relation as indicated by the coefficient of determination R2.