Two Distinctly Separated Emission Colorimetric NIR Fluorescent Probe for Fast Hydrazine Detection in Living Cells and Mice upon Independent Excitations.

Hydrazine is carcinogenic and highly toxic so that it can lead to serious environmental contamination and serious health risks although it has been extensively used as an effective propellant and an important reactive base in industry. Thus, the development of two-emission NIR fluorescent probes for rapid detection of hydrazine with high selectivity and sensitivity is of significance and of great challenge in both biological and environmental sciences. Here, we report a two-emission colorimetric fluorescent probe for the specific detection of hydrazine based on hydrazinolysis reaction under physiological conditions. In the presence of hydrazine, the probe showed an extremely remarkable fluorescence enhancement at 627 nm compared to the decrease at 814 nm excited at different wavelength in aqueous solution. This distinct difference of two emission intensities is suitable for detection of low concentration hydrazine with a detection limit of 0.38 ppb. Addition of hydrazine resulted in a remarkable color change from blue-green to red observed by the naked eye. Kinetic study indicated a fast response of the probe toward hydrazine in minutes. Furthermore, the probe can bioimage hydrazine in living HeLa cells and mice with low cytotoxicity and excellent biocompatibility.