A stable and reproducible nanosilver-aggregation-4-mercaptopyridine surface-enhanced Raman scattering probe for rapid determination of trace Hg2+

A stable nanosilver solution was prepared, using PEG10000 as stabilizer and NaBH4 as reducer. In pH 6.6 Na2HPO4-NaH2PO4 buffer solution containing PEG10000 and NaCl, the nanosilvers (AgNPs) were aggregated to form the stable nanosilver-aggregation (AgNPA) that could conjugate with 4-mercaptopyridine (MPy) to obtain an AgNPA-MPy surface-enhanced Raman scattering (SERS) probe with a strong SERS peak at 1097 cm(-1). When Hg2+ concentration increased, the SERS intensity at 1097 cm(-1) decreased linearly as the stable complex of [Hg(MPy)(2)](2+) was formed and the AgNPA particles precipitate to the bottom. The decreased SERS intensity was linear to Hg2+ concentration in the range of 50-3000 nmol/L. Based on this, a new sensitive SERS method has been proposed for the determination of trace Hg2+ in the water sample, with satisfactory results. (C) 2012 Elsevier B.V. All rights reserved.