Selective and Sensitive Detection of Hg and Ag by a Fluorescent and Colorimetric Probe with Large Stokes Shift.

Development of fluorescent sensors with large Stokes shift for selective detection of heavy metals is of great importance. A novel fluorescent probe with extremely large Stokes shift (212 nm) was synthesized for selective and simultaneous detection of Hg and Ag ions. The deep yellow probe turned colorless or pale yellow after addition of Hg or Ag. The new probe could be utilized for absorption spectral detection of Hg and Ag both in ethanol and aqueous solution. Addition of Hg and Ag ions caused significant decrease in the fluorescence intensity of the new probe and the selective recognition of Hg and Ag was not interfered by common competitive metal ions including Li, Na, K, Cu, Fe, Zn, Co, Ni, Mn, Sr, Ca, Mg, Al, Cr and Fe. The detection limit for Hg and Ag was calculated to be 4.68 μM and 4.29 μM, respectively. Application of the new probe for quantitative determination of Hg and Ag concentrations in real water samples was accomplished.