A novel diaminomaleonitrile-based fluorescent probe for the fast detection of hypochlorite in water samples and foods

Hypochlorite/hypochlorous acid (ClO-/HClO) is one of many species of reactive oxygen species (ROS) that play a vital part in a variety of biological processes. The reliable, effective and rapid detection of ClO- ions is particularly significant for us humans. In this paper, an excellent novel "turn-on" response probe (ENMN) for detecting hypochlorite in different fruits, vegetables and water samples was designed and practically prepared based on diaminomaleonitrile (DAMN). The recognizing researches of ENMN presented a "turn–on" fluorescent response from colorless to blue, and it was found to be highly selective towards various metal ions, anions and reactive oxygen species (ROS). The probe ENMN is facile to synthesize, and showed fast for ClO- (within 5 s) and remarkable stability at a wide pH range (6.0–10.0). The response of ENMN to hypochlorite led to a maximum absorption shift from 385 nm to 320 nm. After treatment with ClO- the probe displayed distinct alterations in absorbance and emission bands with an approximately 434-fold enhancement in fluorescence. A nice linear response range of 0–200.0 μM with the detection limit of 0.169 μM could be fulfilled. NMR, HRMS, IR, and density functional theory (DFT) research findings forcefully sustained the sensing mechanisms which was the CN bond in the probe being oxidated into the CO bond by ClO-. Importantly, the probe ENMN has been not only successfully applied to detect ClO- in buffalo milk (98.3–103.3%), water samples (99.1–109.8%), but also was employed for vegetables and fruits with satisfactory results. Based on its quick response rate, the newly developed probe can be used to real time monitor ClO- in actual water environments and foods.