LAUSR

Abstract A novel phenolphthalein-fluorescein dye derivative ( PF ) was designed, synthesized and characterized. PF showed an effectively selective and sensitive recognition toward Zn 2+ and Hg 2+ ions as a dual channel probe in EtOH-H 2 O (v/v = 8/2, 5 mM, HEPES, pH 7.0) over other cations and the remarkable enhancement in fluorescence emission centered at 500 and 520 nm was observed in the presence of Zn 2+ and Hg 2+ , respectively. The probe PF binds to Zn 2+ and Hg 2+ in 1:2 stoichiometry as determined by a Job's plot, and the binding constants were calculated as 6.45 × 10 10  M −2 and 2.11 × 10 10  M −2 with detection limits of 0.54 μM for Zn 2+ and 1.16 μM for Hg 2+ . Moreover, the results demonstrated that the binding between probe PF and Zn 2+ /Hg 2+ is chemically reversible. To test the practical use of the probe, the determination of Zn 2+ and Hg 2+ in water samples was also evaluated.