A dual functional fluorescent probe based on phenothiazine for detecting Hg2+ and ClO− and its applications

For the efficient detection of Hg and ClO, a double-analyte-responsive fluorescent probe PTB was successfully synthesized by combining N-butyl-3-formyl phenothiazine with hydrazine benzothiazole, and designing a specific reaction site for recognizing two analytes (Hg and ClO) in a compound. It was shown that probe PTB successfully formed a stable complex with Hg in the coordination ratio of 2: 1 by using the strong sulfur affinity of Hg, which resulted in a remarkable "turn-off" effect, with a quenching efficiency of 92.5 % and four reversible cycles of Hg fluorescence detection. For the fluorescence detection of Hg, the response time is fast (≤ 2 min) and the detection limit is low (7.8 nM), showing extremely high sensitivity, and the performance is obviously better than that of the reported fluorescent probes for detecting Hg. In particular, probe PTB has low toxicity and good biocompatibility, and has been successfully used for imaging of Hg in living cells. Moreover, probe PTB uses thioether bond and carbon-nitrogen double bond as reaction sites to detect ClO, which has large Stokes Shift (149 nm), good selectivity, high quenching efficiency (96.5 %) and fast time response (about 10 s), and successfully detects ClO in actual water samples.