A novel conjugated Schiff base-based chemosensor DAP, N¢-((1E,2E)-3-(4-(dimethylamino) phenyl)allylidene)-3-nitrobenzohydrazide, has been synthesized. DAP showed significant selectivity toward mercury ion by color change of pale yellow to orange. Detection limit was 0.11 lM, which is lowerthan the value (2.48 lM) recommended by Health Canada. DAP could recognize and quantify mercury ion in real water samples. The binding mode of DAP and Hg2+ was demonstrated, based on Job plot, IR spectra and ESI-MS.
