In this paper, we reported a new rhodamine derivative bearing 2,4-dichloroquinazoline as a selective
fluorescent chemosensor for Hg2+. The ring-opening process of spirolactam enabled the large fluorescent
enhancement and colorimetric change by Hg2+ induced configuration transformation of the rhodamine.
Moreover, the fluorescence changes of the chemosensor were dramatically specific for Hg2+ in the presence
of other metal ions, which could meet the selective requirements for practical application. Under
optimized experimental conditions, the linear response range covered the concentration range of Hg2+
from 0 to 1.0 106 M, and the limit of detection was calculated to be 2.7 108 M. In addition, the
probe was also successfully applied to the determination of Hg2+ in water samples, test strips and living
cells.