Selective and Sensitive Fluorescence Chemosensor for the Hypochlorite Anion in Water

Based on an oxidized irreversible ring-opening process of the spirolactam of rhodamine 6G to turn on the fluorescence pathway, a highly sensitive, selective fluorescent and easy accessible chemosensor for ClO- has been reported. Upon reaction of the chemosensor with ClO- ions, a fluorescent enhancement factor over 60-fold is observed. The chemosensor shows a remarkably high selectivity to discriminate between ClO- and other ROS, such as H2O2, TBHP etc., and a wide range of the environmentally and biologically relevant anions and metal ions. The oxidized irreversible ring-opening process of the chemosensor also triggers a visible colorimetric change from colorless to pink, leading to production of both "naked-eye" and fluorimetric detection of ClO- anion. The detection limit is estimated to be 2 x 10(-8) M based on a signal-to-noise ratio of 3:1 method. The chemosensor can be used within a pH span of 6-11.5. The chemosensor also shows excellent performance in natural water samples.