An EDTA promoted coordination induced disaggregation for specific Hg2+ detection

Abstract In this work, a novel fluorescent sensing strategy was developed for the detection of Hg 2+ with excellent sensitivity and selectivity using a metal-induced disaggregation of aggregated squaraine molecules with the help of ethylenediaminetetreaacetic acid (EDTA). This EDTA promoted probe exhibited a specific “turn on” fluorescent response to Hg 2+ with a detection limit of 7.6 × 10 −9  M (3 σ / k ). Owning to the high coordinating ability of EDTA and dithiocarbamate tethered squaraine dye toward Hg 2+ , the disaggregation process could be improved by EDTA via the formation of squaraine-Hg 2+ -EDTA trinary complex, resulting in a greater fluorescent release, and this novel phenomenon has been confirmed by light scattering experiments, 1 H NMR, IR and MS.