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 2.5-50mM of AgNO₃ with the reaction time from 0.5-60min. 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 105nm 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 50μgL^-1 for perchlorate.