A dual-responsive fluorescent probe for detection of H2S and Cu2+ based on rhodamine-naphthalimide and cell imaging

A highly selective and sensitive fluorescence probe (DTR-1) for simultaneously detecting H2S and Cu2+ with different fluorescence signals was synthesized. DTR-1 displayed remarkable fluorescence enhancement (560 nm, 34-fold) when H2S was added under excitation of 410 nm with the solution's color change from dark to green. The limit of detection (LOD) for H2S was calculated to be 0.035 mu M. By contrast, the addition of Cu2+ enhanced obviously the emission intensity of DTR-1 with the maximal peak at 630 nm and color change from colorless to orange. LOD for Cu2+ was determined to be 0.16 mu M. The sensing mechanism for H2S and Cu2+ in DMF/PBS (9/ 1, v/v, pH = 7.4) was studied by H-1 NMR and ESI-MS. Furthermore, the potential application of DTR-1 in biological systems had been demonstrated through imaging of living cells.