A novel fluorescent probe based on naphthimide for detecting Zn2+ and its application in plant imaging and cell imaging

The fluorescent probe NXZ was synthesized by introducing –OH at position 1, 8-naphthalimide 4-position and benzimidazole unit at 3-position. The Stokes shift (λ em − λ ex ) of NXZ can up to 148 nm, when Zn 2+ was added to the probe solution, NXZ can quickly form the complex NXZ -Zn 2+ with Zn 2+ in a ratio of 1: 1 within 55 s, and then quench the fluorescence intensity by 4.4 times. The complexation constant of NXZ and Zn 2+ was 1.2 × 10 4 M −1 , and the detection limit for Zn 2+ was 40.3 nM, which is much lower than the maximum Zn 2+ content (76 µM) stipulated in the World Health Organization (WHO). Exploring the practical application of the probe NXZ found that NXZ can be used for the quantitative detection of Zn 2+ in actual water samples and qualitatively detect Zn 2+ in bean sprouts samples and Hela cells. In addition, NXZ can also be made into Zn 2+ test paper.