A highly efficient and selective turn‐on fluorescent sensor for Hg 2+ , Ag + and Ag nanoparticles based on a coumarin dithioate derivative

Based on chelation‐enhanced fluorescence, a new fluorescent coumarin derivative probe 3(1‐(7‐hydroxy‐4‐methylcoumarin)ethylidene)hydrazinecarbodithioate for Hg 2+ , Ag + and Ag nanoparticles is reported. Fluorescent probe acts as a rapid and highly selective “off–on” fluorescent probe and fluorescence enhancement by factors 5 to12 times was observed upon selective complexation with Hg 2+ , Ag + and Ag nanoparticles. The molar ratio plots indicated the formation of 1:1 complexes between Hg 2+ and Ag + with the probe. The linear response range covers a concentration range 0.1 × 10 –5 –1.9 × 10 –5  mol/L, 0.1 × 10 –5 –2.3 × 10 –5  mol/L and 0.146 × 10 –12 –2.63 × 10 –12  mol/L for Hg 2+ , Ag + and Ag nanoparticles, respectively. The interference effect of some anions and cations was also tested. Copyright © 2013 John Wiley & Sons, Ltd.