A ratiometric fluorescent probe with an extremely large emission shift for detecting ClO− and its application in test strips and cell imaging

Hypochlorite (ClO−) is one of the important reactive oxygen species (ROS), which playing an irreplaceable influence towards various physiological activities, it is significant to establish an analytical tool for identifying and monitoring of ClO−. Here, a ratiometric fluorescent probe MYQ with an extremely large emission shift containing 1,8-naphthalimide and benzopyran fluorophores was designed for the detection of ClO−. The probe MYQ presented red fluorescence emission at 655 nm, however, in the presence of ClO−, it exhibited strong blue fluorescence at 462 nm with fluorescent color change from red to blue. Meanwhile, MYQ showed excellent selectivity and selectivity toward ClO− over other common anions in the PBS (60% CH3OH, pH = 7.4) system. The limit of detection for ClO− was calculated to be 25.3 nΜ. The presumed mechanism for detecting ClO− was verified by mass spectrometry and liquid chromatography. Furthermore, the potential practicability of MYQ was demonstrated by strip test and cell imaging.