Eu-MOF based fluorescence probe for ratiometric and visualization detection of Cu²

Water contamination caused by heavy metals represents an urgent global issue. Cu²⁺, a potential trace heavy metal pollutant, can accumulate in the human body through the food chain, leading to excessive levels that give rise to diverse health complications. Hence, in this investigation, a novel and efficacious fluorescent probe named Eu-BTB was developed for the detection of Cu²⁺, employing 1,3,5-triphenyl(4-carboxyphenyl) (H₃BTB) as the ligand and Eu³⁺ as the metallic framework. The probe demonstrates exceptional fluorescence characteristics. The interaction between the probe ligand BTB and Eu³⁺ triggers an antenna effect, heightening the emission efficiency of Eu³⁺ while preserving its intrinsic emission. The introduction of Cu²⁺ competes with BTB for binding, thus quelling the antenna effect and inducing a fluorescence alteration. Within the concentration range of 0.05-10 μM, the fluorescence intensity-to-Cu²⁺ concentration ratio exhibits a robust linear correlation, with a remarkably low detection limit of 10 nM and a rapid response time of 3 min. The fluorescent probe has been effectively deployed for the detection of copper ions in water across diverse environmental conditions, with the obtained outcomes being validated via the conventional approach of inductively coupled plasma mass spectrometry (ICP-MS). The Eu-BTB probe showcases the advantages of simplicity, swiftness, and broad applicability, thus affirming its potential for the prompt and accurate detection of Cu²⁺ in diverse environmental water samples.