Portable sensing of hydrogen peroxide using MOF-based nanozymes

Hydrogen peroxide (H₂O₂) is extensively used in water treatment and food preservation for its pathogen-killing efficacy. Excessive H₂O₂ intake, however, can lead to poisoning with symptoms such as abdominal pain and breathing difficulties. Additionally, small amounts of H₂O₂ may be generated during food preservation, necessitating careful control to meet safety regulations. Real-time detection of H₂O₂ is crucial for process safety and compliance. In this study, a Zr-MOF-based colorimetric fluorescent nanozyme sensor (NH₂-UiO-67(Zr/Cu)) along with a smartphone-assisted portable device were developed for detecting H₂O₂. The sensor, NH₂-UiO-67(Zr/Cu), combines the stable structural properties of Zr-MOF with ligand-generated fluorescence and exhibits peroxidase-like activity. The sensor demonstrated a detection range of 0-1000 μM, with limits of detection (LOD) of 0.0057 μM for the colorimetric assay and 0.0020 μM for the fluorescence assay. Additionally, we designed and developed a portable, smartphone-assisted device using 3D printing technology. This device offers a detection range of 0-750 μM, with LODs of 0.0093 μM in colorimetric mode and 0.0311 μM in fluorescence mode. The developed colorimetric fluorescent nanozyme sensor and portable device show significant potential for the rapid on-site detection of H₂O₂, offering a more convenient and reliable approach for quick identification of analytes in practical applications.