Silver nanoclusters stabilized with denatured fish sperm DNA and the application on trace mercury ions detection

In this study, fluorescent silver nanoclusters (Ag NCs) were synthesized using denatured fish sperm DNA as the template. In contrast to other methods, this method did not use artificial DNA as the template. After their reaction with denatured fish sperm DNA, Ag+ ions were reduced by NaBH4 to form Ag NCs. The Ag NCs showed a strong fluorescence emission at 650nm when excited at 585nm. The fluorescence intensity increased fourfold at pH3.78, controlled with Britton-Robinson buffer solution. The fluorescence of the Ag NCs was quenched in the presence of trace mercury ions (Hg2+) in a weakly acidic medium and nitrogen atmosphere. The extent of the fluorescence quenching of Ag NCs strongly depends on the Hg2+ ion concentration over a linear range from 2.0nmolL(-1) to 3.0molL(-1). The detection limit (3 sigma/k) for Hg2+ was 0.7nmolL(-1). Thus, a sensitive and rapid method was developed for the detection of Hg2+ ions.