A Fluorescence Turn-on Sensor for Hg 2+ with a Simple Receptor Available in Sulphide-Rich Environments

Detection of Hg 2+ in complex natural environmental conditions is extremely challenging, and no entirely successful methods currently exist. Here we report an easy-to-prepare fluorescent sensor B3 with 2-aminophenol as Hg 2+ receptor, which exhibits selective fluorescence enhancement toward Hg 2+ over other metal ions. Especially, the fluorescence enhancement was unaffected by anions and cations existing in environment and organism. Moreover, B3 can detect Hg 2+ in sulphide-rich environments without cysteine, S 2- or EDTA altering the fluorescence intensity. Consequently, B3 is capable of distinguishing between safe and toxic levels of Hg 2+ in more complicated natural water systems with detection limit ≤2 ppb.