A disulfide-linked naphthalimide dimer for Hg(II) detection in aqueous solution

A disulfide linked naphthalimide dimer probe was designed for mercury ion (Hg(2+)) recognition in this work. The recognition was based on the strong affinity of mercury for sulfur. The experimental results revealed that the probe exhibited high selectivity and sensitivity toward Hg(2+) in comparison to other metal ions via a turn-on and reversible response to Hg(2+) in neutral buffer solution. More importantly, the probe demonstrated a linear response for Hg(2+) over a concentration range from 0 to 150 μM with a detection limit of 0.38 μM, which is just the limit of the safe concentration for humans. Upon addition of 150 μM Hg(2+), the enhancement of fluorescence reached a maximum (∼7-fold). The performances of the probe indicated that it could meet the selectivity requirements for biomedical and environmental application and also was sensitive enough to detect Hg(2+) in environmental and biological samples.