A SERS nanocatalytic reaction and its application to quantitative analysis of trace Hg(ii) with Vitoria blue B molecular probe

Abstract

Trace mercury ions can be reduced by NaH₂PO₂ to form nanomercury that can catalyze the NaH₂PO₂ reduction of HAuCl₄ to produce gold nanoparticles (AuNPs) with strong surface-enhanced Raman scattering (SERS) activity. Upon the addition of Vitoria blue B (VBB) as a molecular probe, it adsorbed on the surfaces of the AuNPs with a strong SERS peak at 1612 cm⁻¹. With an increasing concentration of Hg²⁺, the SERS effect enhanced at 1612 cm⁻¹ due to the formation of more AuNPs as substrate generated from the nanocatalytic particle reaction. This new SERS nanocatalytic indicator reaction was studied by SERS, resonance Rayleigh scattering, absorption spectrophotometry and scanning electron microscopy. Under the chosen conditions, 3.0 to 150 × 10⁻⁹ mol L⁻¹ Hg²⁺ can be analyzed quantitatively using SERS, with a detection limit of 0.8 nmol L⁻¹ Hg²⁺.