Luminescent europium(III)-organic framework for visual and on-site detection of hydrogen peroxide via a tablet...

A luminescent metal-organic framework of type Eu(III)-MOF has been fabricated for visual and on-site fluorometric determination of hydrogen peroxide (H₂O₂) via a tablet computer. The maximum excitation and emission peaks of type Eu(III)-MOF were found at λex = 290 nm and λem = 615 nm, respectively. The average length of Eu-MOF is 1.21 ± 0.07 μm. In the presence of the target H₂O₂, Fe²⁺ is transmitted into Fe³⁺ via Fenton reaction, leading to a fluorescence quenching of Eu-MOF. Therefore, visible color change occurred from bright red into colorless. Interestingly, by means of tablet computer's digital camera and ImageJ software, fluorescent signals were captured and transduced into digital parameters, resulting in a linear relationship between fluorescence intensity and the concentration of H₂O₂. As a result, the determination of H₂O₂ without the aid of complicated instruments is achieved in the range 2.0 μM to 0.2 mM with a detection limit of 1.02 μM. Our approach has been successfully applied to quantify H₂O₂ in serum, urine, and waste water with good recovery and precision (< 2.5% RSD). Besides, our assay has been exploited for visual detection of H₂O₂ released from HepG2 cells with the advantages of portability and accuracy. Moreover, the strategy displays acceptable selectivity and stability. Hence, our assay provides an alternative practical method for on-site determination of H₂O₂ without the need for instruments. Graphical abstract Schematic representation of the synthesis procedure of a luminescent Eu-MOF, which has been successfully applied for on-site detection of H₂O₂ via Fenton reaction and imaging analysis technique. The method exhibits handheld and accuracy for H₂O₂ determination, holding the potential for biochemical and clinical applications in remote regions.