Trichloroethylene sensing in water based on SERS with multifunctional Au/TiO₂ core-shell nanocomposites

Herein we report on a rapid and highly sensitive scheme to detect trichloroethylene (TCE), an environmental contaminant, by surface enhanced Raman scattering (SERS) with multifunctional Au/TiO₂ core-shell nanocomposites as SERS substrates. A facile approach to fabricate TiO₂ shell around gold core nanocomposites is proposed as sensors for TCE detection by SERS. During detection, TCE was first oxidized due to the photocatalytic activity of the TiO₂ shell and the increase in SERS intensity due to the product of TCE photooxidation can be used to determine the concentration of TCE. It should be noted that the SERS of the Raman label, 4-mercaptopyridine (4-MPy) modified onto the gold nanoparticle (GNP) core is in proportion to the product of TCE photooxidation. After optimizing the sample pH, enrichment of the analyte, and the UV exposure time, the methodology developed accomplishes an excellent limit of detection (LOD) (0.038 μM, i.e. ∼5 ppb) for TCE in water. Our unique approach based on the synthesized SERS composite to detect TCE, a chlorinated environmental contaminant directly in water could pave the way for the development of a multifunctional nanosensor platform to monitor TCE and the catalytic reactions in a multiplex format.