Silver-nanoparticles/graphene hybrids for effective enrichment and sensitive SERS detection of polycyclic aromatic hydrocarbons.

Polycyclic aromatic hydrocarbons (PAHs) are one of the most widespread and dangerous group of pollutants existing in the environment. Trace detection of PAHs is essential and important. Surface-enhanced Raman scattering (SERS) is a powerful analytical tool for ultrasensitive chemical analysis. However, the direct detection of PAHs by SERS is difficult due to poor affinity of PAHs to metal surfaces. In this work, we present a SERS platform based on the Ag-nanoparticles/graphene hybrid for the direct detection of PAHs with graphene as PAHs assemblies. The target PAHs are captured by the graphene through π-π electronic stacking, and brought close to the hot spots generated by dense Ag-nanoparticles decorated on the graphene. Sensitive detection of PAHs has been realized using this SERS substrate without further surface modification. The limit of detection for the three typical PAHs including pyrene, anthracene and phenanthrene was as low as 0.73 ppb, 1.1 ppb and 0.57 ppb, respectively. Our results indicate that the immobilization of PAHs on graphene is a process that can be applied in the design of sensitive sensors for these aromatic pollutants. This functional SERS sensor shows a great potential application in food safety inspection and environment pollutants monitoring.