A new 4-Amino-7-Nitro-2,1,3-Benzoxadiazole (ANBD)-Based Fluorescent Probe for the Detection of Hg²

Based on the photoinduced electron transfer (PET) principle, 4-amino-7-nitro-2,1,3-benzoxadiazole (ANBD) has been used as a fluorophore to develop a new fluorescent probe, 4-(2-N,N-dimethylthioacetamide)amino-7-nitro-2,1,3-benzoxadiazole (2), for the detection of Hg²⁺. Upon the addition of Hg²⁺, a 46-fold fluorescence enhancement occurs. Moreover the probe 2 exhibits a high selectivity and sensitivity to Hg²⁺, even in the presence of other common metal ions. Under optimal reaction conditions, a good linearity can be obtained in the range of 0.5-2.5 μM, and the detection limit is 0.05 μM. In addition, the desulfurization reaction mechanism is proposed based on electrospray ionization mass spectrum. The present study is not only a supplement to the detection method of Hg²⁺, but also a merit to the development of ANBD-based fluorescent probes.