Highly Sensitive SERS Detection of As3+ Ions in Aqueous Media using Glutathione Functionalized Silver Nanoparticles

A highly sensitive surface-enhanced Raman scattering (SERS) platform for the selective trace analysis of As3+ ions was reported based on glutathione (GSH)/4-mercaptopyridine (4-MPY)-modified silver nanoparticles (AgNPs). Here, GSH conjugated on the surface of AgNPs for specifical binding with As3+ ions in aqueous solution through As-O linkage and 4-MPY was used as a Raman reporter. When As3+ ions were added to the system, the binding of As3+ with GSH resulted in the aggregation of AgNPs, and excellent Raman signal of 4-MPY reporters was obtained which can reflect the concentration of As3+ indirectly. Under optimal assay conditions, the limit of detection (LOD) was estimated to be as low as 0.76 ppb, which is lower than the WHO defined limit (10 ppb), and an excellent linear range of 4-300 ppb was obtained. The practical application had been carried out for determination of As3+ in real water samples.