Determination of trichloroethylene by using self-referenced SERS and gold-core/silver-shell nanoparticles

A surface-enhanced Raman scattering (SERS) method has been developed to determine the concentration of trichloroethylene (TCE) in environmental water. Au-core/Ag-shell nanoparticles containing 4-mercaptophenylboronic acid (4-MPBA) between the core and shell are used as the SERS substrate. 4-MPBA serves as an internal reference with a Raman shift at 534 cm(-1). TCE reacts with 4-mercaptopyridine (4-MPy) in a so-called Fujiwara reaction. With the presence of TCE in water, the consumption of 4-MPy results in a change in the intensity of its Raman signal at 1220 cm(-1). The ratio of the Raman shift at 1220 cm(-1) and 534 cm(-1) decreases linearly in the 0.2 to 1.0 mu M TCE concentration range, and the detection limit of TCE is as low as 8 ppb (60 nM). The method has been successfully applied to the determination of TCE in spiked lake water.