Hypochloric acid (HClO) is a reactive oxygen species (ROS) that functions as a bacteriostatic and disinfectant in food production. Excessive levels of ClO−, however, have been linked to various health issues, including cardiovascular diseases (Halliwell and Gutteridge in Oxford University press, USA, 2015), arthritis, and neurodegenerative diseases (Heinzelmann and Bauer in Biol Chem. 391(6):675–693, 2010). Therefore, synthesizing highly selective and sensitive probes for rapidly detecting endogenous ClO− in daily foods is currently a popular research topic (Kalyanaraman et al. in Redox Biol. 15:347–362, 2018; Winterbourn in Nat Chem Biol. 4(5):278–286, 2008; Turrens in J Physiol. 552(2):335–344, 2003). Thus, we have developed two highly selective ratiometric fluorescent probes (Probe1 and Probe2) based on indole-phenothiazine to detect ClO− in common vegetables, fruits and beverages qualitatively and quantitatively. Moreover, Both Probe1 and Probe2 have shown good specificity and stability, with high fluorescence intensity and long duration (Feng et al. in Adv Sci. 5:1800397, 2018; Wei et al. in Angew Chem. 131(14):4595–4599, 2019; Baruah et al. in J Mater Chem B, 2022).
