A highly sensitive and selective “on-off-on” salamo-like fluorescent sensor for relay recognition of ClO− and SCN

•A new salamo-like fluorescence sensor, EAMS, was developed that can be used for highly sensitive detection of ClO− and SCN− by ratiometric fluorescence.•The sensor EAMS has excellent reproducibility and can be recycled at least five times.•During the reversible detection of analytes by the sensor EAMS, the environmental contamination by these two ions is eliminated by redox interaction between ClO− and SCN−. It is widely acknowledged that ClO− and SCN− can have a deleterious influence on the environment and organisms. As a result, novel approaches for detecting ClO− and SCN− are urgently required. Herein, a new Salamo-like fluorescence sensor (denoted as EAMS) was synthesized, and its high sensitivity and rapid recognition of ClO− and SCN− were achieved through the cleavage and generation of Schiff base (imine) bonds in its molecular structure. Upon addition of ClO−, the fluorescence intensity of the sensor EAMS decreased continuously at 395 nm. Notably, when introducing SCN−, the fluorescence intensity of the sensor EAMS was recovered. The sensor EAMS can sensitively and selectively detect ClO− and SCN− with a detection limit of 2.46 nM and 3.27 nM, respectively. Moreover, the sensor EAMS has excellent reversibility and regeneration, effectively reducing the burden on the environment. Tests in actual water samples also confirmed that the sensor EAMS could be used in the real environment, and has the characteristics of fast response, high selectivity, and high sensitivity. As an innovative, sensitive and low-cost sensor, the sensor EAMS has a good application prospect in pollution detection and pathological research of clinical diseases. [Display omitted]