A flavone-based ESIPT fluorescent sensor for detection of N2H4 in aqueous solution and gas state and its imaging in living cells

•The probe 1 developed here performed a response to hydrazine.•Large emission spectral shift (from weak 408 nm to strong 536 nm) in responding to hydrazine, as a consequence of the ESIPT turn-on.•Hydrazine detection can be undertaken in aqueous solution at neutral pH and the detection limit is 4.8 ppb.•Probe 1 could identify hydrazine vapor even with a concentration down to 0.5%.•The application of probe 1 for hydrazine imaging in HeLa cells was also achieved.

A novel probe (1) based on flavone was synthesized and used for the detection of hydrazine in a mixture of phosphate buffer saline (PBS, pH 7.0, 20 mM) and DMSO (1/9, vPBS/vDMSO) at room temperature. The limit of detection is 0.15 μM (4.8 ppb), which is lower than the U.S. Environmental Protection Agency standard (10 ppb). Notably, probe 1 could be used for gas state discrimination of hydrazine with different concentrations through color changes from readily prepared strips. Additionally, probe 1 could also be applied for the imaging of hydrazine in living cells.

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