A multifunctional water-soluble fluorescent probe based on naphthylimide for detection of Hg²⁺ and formaldehyde with...

In this paper, a multifunctional water-soluble fluorescent probe ANS was designed and synthesized using 1,8-naphthimide as a fluorescent moiety. In HEPES buffer solution at pH 7.4, probe could specifically detect Hg²⁺ and FA with high sensitivity, good immunity to interference, and remarkable visualization, respectively. ANS could complex with Hg²⁺ in a 1:1 ratio with a complexation constant of 5.96 × 10⁴ M^-1, and result in a violet fluorescence at 402 nm, detection limit reach to 4.53 × 10^-8 mol/L. In addition, hydrazine group in its structure could condense with FA to form a hydrazone derivative, at an excitation wavelength of 448 nm that could induce a yellow fluorescence at 550 nm with a detection limit of 2.85 × 10^-7 mol/L. The detection mechanism of the probe for Hg²⁺ and formaldehyde was verified by DFT density functional theory calculations. Finally, the successful applications of ANS in the detection of test strips, seafood, real water samples, and biological cell imaging show that the versatility and high efficiency of ANS provide new possibilities for environmental monitoring, food safety, and medical diagnosis with broad application prospects.