High sensitivity SERS detection of polycyclic aromatic hydrocarbons based on chlorine activation under seawater salinity conditions.

Given that chloride activation can significantly enhance the sensitivity of surface-enhanced Raman scattering (SERS) and that seawater serves as a natural chloride-activating environment, this study systematically investigated the effect of chloride activation on SERS-based detection of polycyclic aromatic hydrocarbons (PAHs). A key finding of this research is that when the chloride ion concentration in the solution approximated the salinity of natural seawater, the SERS detection performance for PAHs was significantly optimized. Specifically, in laboratory experiments with a chloride ion concentration of 0.5 M, the limits of detection (LODs) for naphthalene (Nap), acenaphthylene (Acl), fluorene (Flu), phenanthrene (Phe), anthracene (Ant), fluoranthene (Fla), pyrene (Pyr), and benzo(a)pyrene (BaP) were as low as 1 nM, while the LOD for benzo[k]fluoranthene (BkF) was 5 nM.