A novel benzothiazole-based fluorescent probe for detection of SO2 derivatives and cysteine in aqueous solution and serum

• A new turn-off fluorescent probe HBT-RSS for SO 2 and its derivatives and Cysteine was developed. • The structure of the HBT-RSS was characterized by NMR and X-ray diffraction analysis. • The HBT-RSS provides a new analytical tool for detecting SO 2 and its derivatives and Cysteine in serum. Reactive sulfur species (RSS) and their metabolites play a pivotal role in redox homeostasis and the other physiological processes. SO 2 and its derivatives and Cysteine are double-faced molecule in mammals. Normal amounts of SO 2 and its derivatives and Cysteine have important physiological functions. Instead, they can cause many diseases. Also, these RSS and their metabolites are easily consumed in the environment. For the above reasons, we successfully constructed a novel turn-on fluorescent probe HBT-RSS , which produced increasing signals for detecting SO 2 derivatives and Cys with low detection limit (LOD NaHSO3 = 1.67 × 10 −6 M; LOD Cys = 2.50 × 10 −6 M). The structure of the HBT-RSS was confirmed by 1 H NMR, 13 C NMR, HRMS and X-ray. Moreover, HBT-RSS can be sensitive and selective detected SO 2 derivatives and Cys in BSA or Calf serum.