A dual-emission fluorescence sensor based on TCPP@UiO-66-NH₂ for high-sensitivity detection of copper ions

Copper ions are a significant concern to people's health and wine quality. By adopting a “one-pot” approach, tetra(4-carboxyphenyl)porphyrin (TCPP) molecules were integrated into UiO-66-NH₂ metal-organic frameworks, forming TCPP@UiO-66-NH₂ dual-emission fluorescence sensing platform towards copper ions. The blue fluorescence of UiO-66-NH₂ at 466 nm was deemed an internal reference signal; thus, the built-in corrections in the complex were effectively achieved. The red emission fluorescence of TCPP at 654 nm was quenched by Cu²⁺, resulting in a reliable signal and noticeable color changes. A quick and sensitive ratio fluorescence sensor was constructed with the signal contrast mechanism. This sensor enabled trace detection of Cu²⁺ within the concentration range of 0-10 nM, with a detection limit as low as 24 nM, and exhibited good anti-interference capability and cycling stability. Further spiking-recovery experiments demonstrated excellent detection performance and analytical reliability of the sensor in water and red wine samples.