A smartphone-adaptable chromogenic and fluorogenic sensor for rapid visual detection of toxic hydrazine in the environment

Hydrazine is an essential chemical in industries, but its high toxicity poses great threats to human health and environmental safety. Hence, it is of great significance to monitor the hydrazine in environment. In this work, we presented a chromogenic and fluorogenic dual-mode sensor RA for the detection of hydrazine based on nucleophilic substitution reaction. A linear relationship was obtained between the fluorescence intensity and the concentrations of N 2 H 4 ranging from 0 to 35 μM (R 2  = 0.9936). The sensor can determine hydrazine with fast response (within 12 min), low limit of detection (0.129 μM) and high selectivity. RA was successfully used to detect N 2 H 4 in real water samples with good recoveries and the results corresponded to the standard method. Furthermore, the sensor-coated portable test papers were fabricated, which can visually quantify hydrazine solutions with obvious fluorescence transformation from colorless to red. Moreover, RA -loaded papers were used to create a smartphone-adaptable RGB values analytical method for quantitative N 2 H 4 detection.