A new ratiometric fluorescent chemodosimeter based on an ICT modulation for the detection of Hg2+

We design and synthesize a new ratiometric fluorescent chemodosimeter ( S1 ) for the selective and sensitive detection of Hg 2+ . Upon addition of Hg 2+ , the emission of the S1 exhibits a large bathochromic shift from 393 to 515   nm (up to 122   nm) which is ascribed to an intramolecular charge transfer process in the resultant. The Hg 2+ -induced dethioacetalization for sensing mechanism has been demonstrated by using high-performance liquid chromatography analysis of the sensing process. The interference experiments further demonstrate that S1 exhibits very high selectivity towards Hg 2+ over other coexisting cations/anions. Subsequently, a good linearity of the concentrations of Hg 2+ (0–15   μM) vs the ratiometric signals ( I 515 / I 393 ) allows a fluorogenic method for the quantitative detection of Hg 2+ , with the limitation of detection determined to be 5.22   ×   10 −7   M.