Surface-enhanced Raman scattering sensing of trace fenthion coupled with stable silver colloids and oh stretching band of water as an internal standard

The detection of trace fenthion using surface-enhanced Raman scattering (SERS) was proposed via the OH stretching band of water serving as an internal standard. The adsorption process of fenthion on the silver nanoparticle aggregates was characterized by UV-Visible absorption spectrometry and the optimal adsorption time was about 20 min. The OH stretching band of H2O molecule presented around 3100-3500 [cm.sup.-1] in SERS spectrum was identified by density functional theory and it was not interfered with other characteristic peaks of fenthion. The linearity was obtained from the concentrations divided by the ratio of the benzene ring stretching area around 1073 [cm.sup.-1] and the internal standard of OH stretching area from 3100 to 3500 [cm.sup.-1], while the detection limit was calculated as 0.46 pM. The proposed SERS detection method was used in analyzing lake water sample with the recovery of 94-99%. Keywords: fenthion, surface-enhanced Raman scattering, silver nanoparticle aggregates, internal standard
Fenthion is widely used as an organophosphorous pesticide by inhibiting the activities of acetyl cholinesterase, but the residue of fenthion has been reported a high mammalian toxicity [1]. The maximum [...]