A novel reversed reporting agent method for surface-enhanced Raman scattering; highly sensitive detection ofglutathione in aqueous solutions

摘要

In this study, a new application method for SERS named ‘‘reversed reporting agent’’ method isnproposed for selective detection of biomolecules with a thiol group. In this method reporting agentsnsuch as rhodamine 6G (R6G) are capped on surfaces of silver colloidal nanoparticles. Analytes havingna thiol group will replace the positions of reporting agents due to the strong interactions between silvernand the thiol group, and then the SERS intensity of the reporting agents will be reduced. By monitoringnthe difference in the SERS intensity of reporting agents before and after the replacement of analytes, thenconcentration of the analytes can be estimated. To demonstrate the feasibility of this proposed method,nglutathione was used as the analyte and R6G, crystal violet (CV), and thiacyanine (TC) were employednas the reporting agents, and factors that affect the capability of the determination of glutathione wereninvestigated. The results indicate that R6G is the most suitable reporting agent, and the concentrationnof the reporting agents affects the sensitivity and selectivity of glutathione determination. Under thenoptimal conditions, the detection of glutathione can be finished within 20 minutes and the detectionnlimit of ca. 1 mMcan be achieved. Furthermore, the proposed method holds specific selectivity towardsnglutathione, which means it has possible practical applications.