Perylene monoimide-based red-emitting ratiometric fluorescent probe for rapid and selective hypochlorite monitoring and machine learning-assisted sensing analysis

Hypochlorite (ClO⁻) is a highly reactive oxygen species (ROS) that plays a crucial role in the resistance against microbial attacks. Moreover, ClO⁻ is widely used as a bleaching and disinfecting agent in daily life. However, its excessive use may lead to aquatic animal deaths and human respiratory. Thus, developing a rapid ClO⁻ detection tool for the environment and pathology is crucial. In this paper, we report the synthesis of a fluorescence probe (PMIS), which is constructed by integrating the perylene monoimide (PMI) core with the thioether moiety. Based on the intramolecular charge transfer (ICT) mechanism, PMI-S undergoes the thioether oxidation process, enabling it to specifically recognize ClO⁻ with high selectivity, rapid response (15 s), and a low detection limit (DL) of 38.8 nM. PMI-S showed a blue-shift in fluorescent emission from 613 nm to 499 nm in response to ClO⁻. Moreover, the recognition process was systematically elucidated through high-resolution mass spectrometry, ¹H NMR titration, and DFT theoretical calculations. Capitalizing on its remarkable sensing performance, PMI-S demonstrated high-accuracy quantification of ClO⁻ contaminants in aquatic environments, with spiked recovery rates spanning 95.5–103.5 %. Furthermore, we engineered a tri-platform detection system comprising (i) PMI-S-functionalized paper sensors, (ii) a smartphone-assisted chromatic analysis platform for instantaneous on-site ClO⁻ monitoring and (iii) a machine learning-assisted sensing analysis method.