Construction of a Graphene/Au‐Nanoparticles/Cucurbit[7]uril‐Based Sensor for Pb 2+ Sensing

The development of highly sensitive and selective methods for the detection of lead ion (Pb 2+ ) is of great scientific importance. In this work, we develop a new surface‐enhanced Raman scattering (SERS)‐based sensor for the selective trace measurement of Pb 2+ . The SERS‐based sensor is assembled from gold nanoparticles (AuNPs) and graphene using cucurbit[7]uril (CB[7]) as a precise molecular glue and a local SERS reporter. Upon the addition of Pb 2+ , CB[7] forms stronger complexes with Pb 2+ and desorbs from AuNPs, resulting in a sensitive “turn‐off” of SERS signals. This SERS‐based assay shows a limit of detection (LOD) of 0.3 n m and a linear detection range from 1 n m to 0.3 μ m for Pb 2+ . The feasibility of the assay is further demonstrated by probing Pb 2+ in real water samples. This SERS‐based analytical method is highly sensitive and selective, and therefore holds promising applications in environmental analysis.