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.
Keywords: Cell released; Fenton reaction; Fluorescence; H2O2; Lanthanide; MOF; Metal-organic framework.