Rhodamine-Based Fluorescent Probe for Highly Selective Determination of Hg.

The determination of mercuric ions (Hg) in environmental and biological samples has attracted the attention of researchers lately. In the present work, a novel turn-on Hg fluorescent probe utilizing a rhodamine derivative had been constructed and prepared. The probe could highly sensitively and selectively sense Hg. In the presence of excessive Hg, the probe displayed about 52-fold fluorescence enhancement in 50% HO/CHCHOH (pH, 7.24). In the meantime, the colorless solution of the probe turned pink upon adding Hg. Upon adding mercuric ions, the probe interacted with Hg and formed a 1:1 coordination complex, which had been the basis for recognizing Hg. The probe displayed reversible dual colorimetric and fluorescence sensing of Hg because rhodamine's spirolactam ring opened upon adding Hg. The analytical performances of the probe for sensing Hg were also studied. When the Hg concentration was altered in the range of 8.0 × 10 to 1.0 × 10 mol L, the fluorescence intensity showed an excellent linear correlation with Hg concentration. A detection limit of 3.0 × 10 mol L had been achieved. Moreover, Hg in the water environment and A549 cells could be successfully sensed by the proposed probe.