A Rapid Surface-Enhanced Raman Scattering Method for the Determination of Trace Hg2+ Using Rhodamine 6G-Aggregated Nanosilver as Probe

In pH 6.0 Na2HPO4-NaH2PO4 buffer solution and in the presence of cetyltrimethyl ammonium bromide, nanosilver particles were aggregated to a stable suspension. Therein, rhodamine 6G (Rh6G) exhibited three strong surface-enhanced Raman scattering (SERS) peaks at 613, 1,363, and 1,510 cm(-1), and their SERS intensities were enhanced when the concentration of Rh6G increased. In the presence of Hg2+, the SERS intensity decreased greatly owing to formation of stable Rh6G-HgBr (4) (2-) ternary association complex molecules as well as its particles. In the optimal condition, the decreased SERS intensity at 613 cm(-1) responds linearly with the concentration of Hg2+ over 25-2,000 nmol/L. Thus, a new sensitive SERS method has been proposed for the determination of trace Hg2+ in the water sample, with satisfactory results.