A highly sensitive and selective detection of Hg(II) in 100% aqueous solution with fluorescent labeled dimerized Cys residues.

A simple design of a ratiometric fluorescent sensor for detecting Hg(II) ion in 100% aqueous solution was demonstrated, based on the structure of dimerized Cys residues with two dansyl fluorophores. The sensor highly sensitively and selectively detected mercury ion (K(d) = 41 nM) in 100% aqueous solution via a turn-on and ratiometric response. The sensor showed no interferences of other metal ions and satisfied for monitoring the maximum allowable level (2 ppb) of mercury ion in drinking water demanded by EPA via a turn-on response.