Hg2+-selective ratiometric and colorimetric probe based on dansyl-rhodamine and its staining function in cell imaging

A new ratiometric probe composed of a dansyl-rhodamine dyad for the detection of Hg2+ via fluorescence resonance energy transfer was designed and synthesized. Rhodamine, dansyl chloride, and hydrazide were selected as the acceptor, donor, and reaction site, respectively. It displayed high selectivity and sensitivity to Hg2+ with obvious colour change and fluorescence change due to Hg2+-assisted hydrolysis of rhodamine hydrazide. A good linear relationship ranging from 0 to 16 mu M and 0-28 mu M for the Hg2+ concentration was found based on absorbance and fluorescence assay, respectively. Detection limits of absorbance and fluorescence for Hg2+ were calculated to be 1.22 mu M and 9.10 mu M, respectively.