A novel phenoxazine-Meldrum's acid D-π-A fluorescent sensor for “turn-on” detecting hydrazine and its applications to practical samples analysis, plant and animal imaging

In this study, a new phenomena-Meldrum's acid D-π-A fluorescent sensor 5-((10-(2-ethoxyethyl)−10H-phenoxazin-3-yl)methylene)−2,2-dimethyl-1,3-dioxane-4,6-dione (PM) was developed, which was employed for colorimetric and turn-on fluorimetric sensing hydrazine in ~100% aqueous media. The sensor PM towards hydrazine shows excellent selectivity with strong anti-interference capability, high sensitivity with extremely low detection limit of 4.2 nM, ultra-rapid response (15 s) and broad pH application range (5−9). The proposed mechanism of sensor PM for sensing hydrazine was supported by 1H NMR, FTIR, HRMS analyses and fluorescence titration studies. The sensor PM not only provides an effective tool for quick and on-site detecting gaseous and aqueous N2H4 in paper strips with sensitive naked-eye color diversification, but also is capable of quantitatively and sensitively detecting trace levels of N2H4 in environmental, biological, plant and food samples. More importantly, the sensor PM was successfully utilized for bio-imaging of N2H4 in plants and animals. As expected, the hydrazine-sensing method in this work is of great significance for further biological applications.