A Novel Donor-Acceptor Fluorescent Sensor for Zn²⁺ with High Selectivity and its Application in Test Paper

A novel donor-acceptor fluorescent sensor was designed and synthesized. The sensor exhibited high selectivity and sensitivity to Zn²⁺ in acetonitrile solution. When 3.0 equiv. of Zn²⁺ was added gradually, the emission intensity at 500 nm increased 54-fold, accompanied by the fluorescent color of the solution changed from dark to green. Job's plot and ESI-MS were carried out to verify a 1:1 stoichiometric complex was formed between the sensor and Zn²⁺. The limit of detection (LOD) to Zn²⁺ was measured to be 2.81 × 10^-9 mol L^-1. Moreover, the sensor not only could be used to detect Zn²⁺ in practical water samples with high accuracy, but also could be made into test paper for the qualitative detection for Zn²⁺.