A highly selective NIR fluorescent probe for Hg²⁺ and its multiple application in biological and environmental systems

A novel near-infrared (NIR) fluorescent probe based on twisted intramolecular charge transfer (TICT) effect was designed and synthesized for establishing a sensitive method for detecting Hg²⁺. After the addition of Hg²⁺, the interaction between the probe and Hg²⁺ causes the thiocarbonate to fall off, resulting in a red shift of the absorption peak of the probe. The linear detection range of the probe for Hg²⁺ was 0–0.1 μM and the detection limit was 6.57 nM. This method had excellent selectivity, sensitivity and anti-interference ability in detecting Hg²⁺. In the real sample experiments, the recovery rate of the probe to Hg²⁺ was from 93.79 % to 101.80 % in the detection system made of different concentrations of Hg²⁺ in water and food samples, indicating that the probe has corresponding research value in the field of environmental monitoring and food testing. Biological experiments had proved that the probe not only had low cytotoxicity, but also successfully achieved visual detection of Hg²⁺ in cells and zebrafish.