Novel rhodamine based chemosensor for detection of Hg~(2+): Nanomolar detection, real water sample analysis, and intracellular cell imaging

摘要

A novel fluorescent chemosensor PS founded on rhodamine 6G for Hg~(2+) has been synthesized and authenticated by employing ~1H NMR, ~(13)C NMR, and LC-MS skills. The fluorescent chemosensor displays an intense selectivity and sensitivity for Hg~(2+) over additional metal ions explored in the combined organic aqueous phase. A strong fluorescence enhancement was detected after the addition of Hg2*, which was accompanied by ring-opening of a rhodamine spiro-cyclic structure. The stoichiometric ratio of the PS-Hg~(2+) complexes was determined to be 1:1 according to Job's plot and !H NMR experiment. The binding constant and limit of detection (LOD) for PS-Hg~(2+) complexation is estimated to be 6 × 10~4 M~(-1) and 3.0375 × 10~8 M (30.37 nM), respectively. The extreme fluorescent enhancement caused by Hg~(2+) binding in chemosensor PS occurred at a pH range of 6-8. Owing to practical application, the Hg~(2+) metal ion was efficiently determined using a spike and recovery approach from real water samples. Additionally, the probe PS was further used in the cell imaging experiment for the detection of the Hg~(2+) intracellularly using MDA-MB-231 and A375 breast cancer cells by MTT assay method with low cytotoxicity.