A fluorescence turn-on sensor for Hg2+ 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.