Silver nanoparticle aggregates on copper foil for reliable quantitative SERS analysis of polycyclic aromatic hydrocarbons with a portable Raman spectrometer

Abstract

Silver nanoparticle aggregates were synthesized on copper foil, which was used for the surface-enhanced Raman spectroscopy (SERS) detection of polycyclic aromatic hydrocarbons (PAHs) with a portable Raman spectrometer. Silver nanoparticle aggregates were prepared by immersing copper foil in the solution of Sn²⁺ and AgNO₃ in a cyclic fashion. A four-cycle process was selected for the following experiments due to its high enhancement and relatively convenient experimental procedure. The substrate has greater temporal stability under continuous laser radiation, good uniformity and reproducibility, which indicated that the substrate could provide reliable measurements. The relationship between SERS intensity and concentrations of PAHs was studied. Quantitative analysis of PAHs in aqueous solution was further performed based on the prepared substrate. The log–log plot of normalized SERS intensity to PAHs concentration exhibited a good linear relationship, with the detection limits in the range of 5–500 μg L⁻¹. Thus, due to the stability, reproducibility and quantitative results, the prepared substrate could be used as a potential SERS sensor for the analysis of environmental pollutants.