Highly selective chromogenic and fluorogenic probe based on benzothiazole-thiosemicarbazone Schiff base for detection of copper (II) in real samples

Copper is the third most abundant essential transition metal ion in the human body. It's responsible for important activities in many living things, but excessive intake of Cu²⁺ can lead to a range of diseases. A colorimetric and turn-off fluorescent probe (E)-2-(5-(benzothiazol-2-yl)-2-(diethylamino)-4-hydroxybenzylidene)-N-phenylhydrazine-1-carbothioamide ( ZTR ) was designed and synthesized by thiosemicarbazone Schiff base as a specific complexes site strategy to achieve highly specific Cu²⁺ detection. The fluorescence of the probe ZTR solution fell dramatically when Cu²⁺ was added, and its appearance changed from dazzling blue to nearly colorless. The simple structure and readily available fluorescent probe provide a novel approach for the quantitative detection of Cu²⁺ in the linear range from 0 to 0.12 μM, with a detection limit down to 16 nM, and with high selectivity for Cu²⁺ over 15 other metal ions. Job’s plot analysis showed that probe ZTR and Cu²⁺ formed a 1:1 coordination complex. In addition, because of its low detection limits and fast response time, the created fluorescent molecule was effectively used to study the target ions on test paper strips and in water samples.))