The thallium is widely used in various research and industrial applications but is very toxic. In this work, we developed a novel reaction-based dual signaling probe for the selective and sensitive determination of Tl³⁺ via the oxidative cleavage of a rhodamine–dansylhydrazide conjugate. The designed probe showed pronounced colorimetric and fluorescence signaling behavior toward Tl³⁺ with a detection limit of 1.3 × 10^–7 M (0.027 ppm), as well as selectivity over other common metal ions, anions, and oxidants. The Tl³⁺ signaling process required less than 2 min and was not influenced by the solution pH within the range of 4.0–5.5; however, the signal diminished significantly above pH 6.0. To demonstrate the practical applicability of the designed probe, a simple and convenient colorimetric assay for the determination of Tl³⁺ in commercial reagents was established using an office scanner as a readily available signal capturing device.

al广泛用于各种研究和工业应用中，但毒性很高。在这项工作中，我们开发了一种新型的基于反应的双重信号探针，用于通过罗丹明-丹磺酰肼共轭物的氧化裂解来选择性和灵敏地测定Tl ³⁺。设计的探针对Tl ³⁺表现出明显的比色和荧光信号行为，检出限为1.3×10 ^–7 M（0.027 ppm），并且对其他常见金属离子，阴离子和氧化剂具有选择性。Tl ³⁺信号传递过程需要少于2分钟，并且不受溶液pH值在4.0-5.5范围内的影响；但是，在pH 6.0以上时，信号明显减弱。为了证明所设计探针的实际适用性，使用办公室扫描仪作为现成的信号捕获设备，建立了一种用于测定商业试剂中Tl ³⁺的简单便捷的比色测定法。