A ratiometric fluorescent probe with large Stokes shift and emission shift for sensing hydrazine in living organisms

As a highly toxic reagent, hydrazine (N2H4) is notorious to human beings and the environment. To simply and conveniently detect N2H4 in environmental and biological systems, a ratiometric fluorescent probe MA-N2H4 was developed with excellent sensitivity and selectivity. Probe MA-N2H4 was readily prepared based on a naphthalene as the fluorescent scaffold and an indanedione group as the responsive moiety for N2H4. This probe displayed a red-emitting fluorescence at 670 nm with a large Stokes shift (200 nm). After treatment with N2H4, a significant blue-shifted emission at 440 nm could be observerd, which led to an extremely large emission wavelength shift (230 nm). The fluorescent intensity ratio (I440/I670) of probe MA-N2H4 was rapidly and significantly increased (273-fold) within 18 min. The detection limit for N2H4 was 0.5 µM. In addition, the probe was successfully employed for tracking N2H4 in living cells and zebrafish through a ratiometric manner.