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

Synthetic procedure of Eu-BTB and detection mechanism toward copper ions . • The synthesized Eu-MOF has stable fluorescence emission. • Cu 2+ can break the “antenna effect” between Eu-BTB and change the fluorescence emission. • The constructed ratio fluorescence sensor can effectively eliminate background interference. • It has been successfully applied to three real samples of different water bodies. Water contamination caused by heavy metals represents an urgent global issue. Cu 2+ , 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 Cu 2+ , employing 1,3,5-triphenyl(4-carboxyphenyl) (H 3 BTB) as the ligand and Eu 3+ as the metallic framework. The probe demonstrates exceptional fluorescence characteristics. The interaction between the probe ligand BTB and Eu 3+ triggers an antenna effect, heightening the emission efficiency of Eu 3+ while preserving its intrinsic emission. The introduction of Cu 2+ 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-Cu 2+ 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 Cu 2+ in diverse environmental water samples.