Resonance scattering spectral detection of ultratrace Hg(II) using herring sperm DNA modified nanogold probe as catalyst

摘要

Herring sperm DNA (hsDNA) was used to modify 10 nm nanogold to obtain a resonance scattering (RS) probe (AuhsDNA) for detection of Hg~(2+). In the presence of salt, Hg~(2+) interacts with AuhsDNA to form stable Hg~(2+)-hsDNA complexes, and releases nanogold particles to form larger nanogold clusters that can be removed by membrane filtration. The excess AuhsDNA in the filtrate solution exhibits a catalytic effect on the reaction between hydroxylamine (NH_2OH) and Cu(II). The excess AuhsDNA decreased with the addition of Hg~(2+), which led the RS intensity at 602 nm to decrease. The decreased RS intensity (Δl_(602 nm)) had a linear response to Hg~(2+) concentration in the range of 0.4-400 nM, with a detection limit of 0.2 nM Hg~(2+). This RS method was applied for the detection of Hg~(2+) in water samples, with sensitivity, selectivity and simplicity.