AbstractTo rapidly detect polycyclic aromatic hydrocarbons (PAHs) in coastal seawater, a portable surface-enhanced Raman scattering (SERS) sensor was designed and assembled. A large number of halide ions are present in seawater, and they easily combine with gold nanoparticles,
which results in a significant SERS enhancement effect for PAHs. Therefore, a mixture of a gold colloid solution and NaCl solution that forms a large number of highly sensitive SERS-active clusters was used in this study. The extinction intensity of the gold colloid solution at 785 nm—that
is, the SERS excitation wavelength—was greatly increased by the addition of Cl−. The SERS sensor was applied in five different coastal environments, and six or seven types of PAHs were detected without further sample processing. The seawater samples were also analyzed
using a gas chromatography-flame ionization detector (GC-FID) for comparison and confirmation of the results. Ten to 13 types of PAHs were detected by GC-FID after dehydration, purification, and concentration under nitrogen, and naphthalene was not detected because of its volatility. The SERS
sensor was proven to be a suitable alarm sensor for the in-situ detection of PAHs in coastal seawater and is proposed for use as a real-time qualitative and quantitative PAH monitoring sensor in the near future based on its promising improvement in sensitivity.
Detection of polycyclic aromatic hydrocarbons by surface enhanced Raman scattering on colloidal silver substrates
