Ultra-sensitive, versatile and portable detection of hydrazine in eco-environmental systems using a smartphone-integrated ratiometric fluorescent sensor.

Hydrazine (NH), a highly reactive specie widely used in industrial processes, poses significant ecological risks. Accurate detection of NH is essential for safeguarding public health, yet developing a robust tool for its global detection remains a significant challenge. Herein, we developed a ratiometric fluorescent sensor, DIPOT, designed for ultra-sensitive and portable detection of NH in eco-environmental systems. DIPOT exhibited excellent ratiometric fluorescence performance for NH in aqueous solution, with a detection limit as low as 4.5 nM and a substantial 156 nm blue shift, transitioning from red to green fluorescence. We integrated it into portable test strips for on-site quantitative detection and analysis of NH vapor and solution via a smartphone application. DIPOT and its portable platform have been successfully applied to monitor ultra-trace levels of NH in 20 diverse eco-environmental samples, including water, soil, crops, food and living organisms, showcasing its versatility. Furthermore, DIPOT facilitates real-time ratiometric bioimaging of NH in living plants, cells and zebrafish. Our findings provide a robust and eco-friendly approach for global tracking of NH, representing a significant advancement in environmental sensing technology.