A Novel Fluorescent Probe for Zn²⁺ Detection in Aqueous and Application in Environmental Samples and Cells Bioimaging

A novel salicylaldehyde-benzohydrazide-based fluorescent probe L was designed and synthesized. The probe displayed excellent specificity and sensitivity for Zn²⁺ detection in aqueous media (HEPES buffer, pH = 7.40), accompanied by a remarkable colorimetric fluorescence change from colorless to green under a 365 nm UV lamp. The detection mechanism of probe L for Zn²⁺ was elucidated by ¹H NMR, HRMS, and DFT calculation. Moreover, the probe was effectively applied in the detection of Zn²⁺ in both environmental samples and biological imaging in living cells.