A highly sensitive turn-on fluorescent sensor for hydrazine based on conjugated D-π-A molecule

Owing to the extreme toxicity of hydrazine to human body, it is urgent to develop highly sensitive visual N2H4 sensors. In this paper, a donor-π-acceptor (D-π-A) molecule DTZ-TPA-CHO was synthesized and its chemical structure was characterized by spectrum analysis. The sensor displayed good stability and highly selectivity for detection of hydrazine through fluorescence opening, and about thirty kinds of ions and various amino acids and amines have no influence. The association constant and lowest detection limit was calculated to be 3.52 × 1010 M−1 and 7.9 nM, respectively. Besides, the sensor was also exhibited outstanding property of alkali resistance, and its fluorescence intensity tended to be consistent at pH value range from 4 to 13. A hydrazone-formation mechanism of probe DTZ-TPA-CHO for detection of hydrazine based on intramoleculer charge transfer (ICT) was analyzed by 1H NMR, ESI-MS spectrum and DFT calculations. It is worth mentioning that the react energy of every step was creatively counted, making known the reaction is easy to proceed in view of thermodynamics. Test strips and spray based on the sensor were fabricated, demonstrating it could be acted as a convenient and efficient hydrazine test kit to detect hydrazine for “in-the-field” measurement, and the results indicated its potential utility for N2H4 sensing in environmental samples.