Trace mercury ion determination based on the highly selective redox reaction between stannous ion and mercury ion enhanced by gold nanoparticles

A novel resonance light scattering (RLS) spectrometric method for mercury ions (Hg2+) determination has been established in this article. Mercury (Hg) nanoparticle formed from the highly selective redox reaction between citrate-stabilized stannous ions (Sn2+) and Hg2+. As a result, the RLS intensities of the system can be enhanced and it can be sensitized in the presence of very little amount of gold nanoparticles (AuNPs). According to this phenomenon, trace Hg2+ in real water sample has been determined directly by RLS spectrometry. It has been found that the enhanced RLS intensities (ΔIRLS) characterized at 395 nm are proportional to the concentration of Hg2+ in the range of 0.1–30 μmol L−1 with a detection limit (3σ) of 0.051 μmol L−1. The method described herein has good sensitivity, selectivity, and without complicated sample pretreatment. Moreover, the feasibility for the analysis of Hg2+ in a wastewater sample was identified with a good recovery (100.2–106.3%).

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► This approach proposed for the determination of Hg2+ in water sample based on the redox reaction of “Hg2+ + Sn2+ = Hg + Sn4+”.
► The resonance light scattering (RLS) signal greatly enhanced in the present of little amount of AuNPs.
► The probe used in this method is a kind of common inorganic compound as the solution of Sn2+ stabled with trisodium citrate.
► The method described herein has good sensitivity, selectivity and without complicated sample pretreatment.