A dual-function fluorescent probe (Probe 1) was developed for discriminative detection of Hg and N H . Probe 1 could discriminatively detect Hg and N H through two different reaction sites, with the mechanism for Probe 1 for Hg depending on a desulfurization reaction and for N H depending on the Schiff-base reaction. N H had minimal effect on Hg detection in dimethyl sulfoxide (DMSO)/H O solution, but Hg could interfere with N H detection in DMSO/buffer solution. Different concentrations of Hg and N H resulted in different blue shades of Probe 1 test strips, and the shade of blue was different with the same concentration of Hg or N H , as observed under ultraviolet light at 365 nm wavelength.