A dansyl-based fluorescent probe, 2-((5-dimethylamino)naphthalene-1- sulfonamido)acetic acid (DNSG), was synthesized from dansyl chloride and glycine. In HEPES buffer (20 mM, pH 6.7), DNSG could detect Hg2+ by fluorescence quenching. The maximal fluorescence intensity showed a good linear relationship with the Hg2+ concentration (0 similar to 80 mu M). The detection limit was 0.33 mu M. With the help of silk fibroin (0.076 g/L), DNSG could detect Hg2+ by fluorescence enhancement and blueshift. The linear concentration range for Hg2+ was 0 similar to 160 mu M with a detection limit of 0.81 mu M. DNSG could detect Hg2+ quickly and reversibly with excellent anti-interference ability and further could assay environmental water sample efficiently. The sensing mechanism was examined by Job's plot, mass spectrum and H-1 NMR analysis. GRAPHICS .
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