A label-free SERS sensor for the detection of Hg2+ based on phenylacetylene functionalized Ag nanoparticles

Abstract

The development of a facile, rapid, precise, and ultrasensitive assay for the detection of mercury ions (Hg2+) is an urgent problem to be solved because excessive Hg2+ poses a great threat to human health and the ecological environment. Herein, a novel surface-enhanced Raman scattering (SERS) sensor which employed phenylacetylene (PA) as a label-free probe was established. The PA functionalized silver nanoparticles (PA-AgNPs) produced an intense SERS signal in the Raman-silent region, which effectively avoided the interference of solvent and overcame the signal overlap problem. In the presence of Hg2+, the PA molecules separated from the Ag surface due to the strong coordination between the alkynyl group and Hg2+, which resulted in a significant SERS signal attenuation. Basing on the proposed SERS platform, a linear relationship with a wide range from 10–10 to 10–8 M and a low detection limit of 87.6 pM were obtained. Besides, the selectivity and reproducibility of the SERS system were also investigated. What’s more, we applied the SERS sensor to analyze Hg2+ in lake water with high accuracy and excellent recovery. The obtained results demonstrated that the established SERS platform is expected to be a promising alternative tool for the determination of Hg2+ in practical application.