A novel colorimetric probe RP1 was synthesized using rhodamine derivatives and heterocyclic compounds for the purpose of detecting Cu²⁺. RP1 showed good selectivity, high sensitivity and affinity toward Cu²⁺ over other competing ions in CH₃OH–H₂O (1/1, v /v) solution. Absorbance intensity showed a good linear fit between probe R1 and Cu²⁺ over the concentration range 1–8 μM and the association constant was also calculated to be 1.145 × 10⁵ M⁻¹. The sensing mechanism was deduced using Job's plot, Fourier transform infrared spectroscopy, and density functional theory studies. In addition, the colorimetric experiment indicated that probe RP1 could be made into test paper to detect Cu²⁺ with a colour change from colourless to pink.

中文翻译：

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一种用肉眼检测Cu2 +的比色探针，并应用于试纸中。

为了检测Cu ^2+，使用罗丹明衍生物和杂环化合物合成了一种新型比色探针RP1。RP1在CH ₃ OH–H ₂ O（1 / 1，v / v）溶液中显示出比其他竞争离子更好的选择性，高灵敏度和对Cu ^2+的亲和力。在浓度范围1–8μM范围内，吸光度在探针R1和Cu ²⁺之间显示出良好的线性拟合，并且缔合常数也计算为1.145×10 ⁵ M ^-1。使用乔布斯图，傅立叶变换红外光谱和密度泛函理论研究推导了传感机制。另外，比色实验表明，可以将探针RP1制成试纸，以检测颜色从无色变为粉红色的Cu ²⁺。