In situ regulation nanoarchitecture of Au nanoparticles/reduced graphene oxide colloid for sensitive and selective SERS detection of lead ions.

In this work, the colloid of Au nanoparticles (AuNPs)/reduced graphene oxide (rGO) was synthesized by growth AuNPs on rGO via the reduction of HAuCl4 on graphene oxide (GO) nanosheets. The nanoarchitecture of the colloid could be controllably regulated through in-situ Pb(2+)-enhanced gold leaching reaction, which made the colloid be a flexible surface-enhanced Raman scattering (SERS) platform for Pb(2+) detection. Upon the addition of Pb(2+), the Raman signal of graphene underwent significant descent due to the decrease of the amount of the "hot spots", which was originated from Pb(2+)-accelerated dissolution of AuNPs on the graphene surface in the present of thiosulfate (S2O3(2-)). Based on the change of SERS signal through in situ regulation the nanoarchitecture of the colloid, a sensitive and selective strategy for Pb(2+) measurement was developed with a linear range from 5nM to 4μM as well as a low detection limit of 1nM. Furthermore, the SERS-based method was applied for the determination of Pb(2+) in water samples with satisfactory results.