Dual Recognition Exhibiting a Polymeric Fluorescent Probe for Specific Detection and Removal of Hydrazine

Sensitive and specific detection of hydrazine (N2H4) is of great importance for environmental ecology and human health due to its high biotoxicity. However, the selectivity of most existing N2H4 probes relies on the reaction with one of the nucleophilic groups (−NH2) of N2H4, which cannot effectively discriminate N2H4 from other amino compounds. Herein, we report a coumarin-appended polymeric probe (CFPF) for the selective detection and removal of N2H4 in water solutions. By cross-linking aldehyde-coumarins with the acetylphenyl moieties on polystyrene, the polymeric multivalent probe was obtained, which endowed the polystyrene with excellent fluorophores and multiple electrophilic sites for special reaction with N2H4. In the presence of various competitive species, CFPF offers highly sensitive, specific, and rapid response to N2H4. The preliminary mechanism investigation revealed that the change in optical signal resulted from N2H4-mediated chalcone or chlorobuta-1,3-diene cyclization. The CFPF-based method for detecting N2H4 gives a limit of detection (LOD) of 4.19 nM, which is lower than that suggested by USEPA (TLV, 10 ppb). Furthermore, a CFPF-loaded bead device was fabricated and used to monitor and extract N2H4 in the wastewater samples. The reaction-specific and stable characteristics of CFPF-beads led to the extraction of trace N2H4 from the water body. Overall, the proposed polymeric probe indicates its potential application for N2H4 sensing and trapping in water samples and represents a prospective multivalent probe for practical applications.