Surface-enhanced Raman scattering analysis of perchlorate using silver nanofilms deposited on copper foils

Surface-enhanced Raman scattering (SERS) has recently emerged as a tremendous potential method for chemical and biomolecular sensing. SERS analysis of perchlorate using Ag nanofilms deposited on Cu foils (Ag–Cu films) by galvanic displacement reaction was investigated for the first time in this work. The Ag–Cu films were prepared in the solutions containing 2.5–50 mM of AgNO3 with the reaction time from 0.5–60 min. The relationship between the surface nanostructures of the Ag–Cu films and the SERS sensitivity of perchlorate was examined. The close-packed Ag nanoparticles with an average diameter of 105 nm yielded the highest SERS enhancement for perchlorate. Standard calibration curves were prepared with SERS spectra recorded on this optimum Ag–Cu film. At low concentration and in a narrow concentration range, a linear relationship between peak areas and perchlorate concentrations was observed, while a log–log plot yielded a linear relationship over a broad concentration range. The detection limit was determined to be 50 μg L−1 for perchlorate.