V4O7 microcubes as an alternative to peroxidase/TMB for colorimetric detection of H2O2: Development of glucose sensing method.

Abstract

The study focuses on the synthesis of V₄O₇ microcubes for the non-enzymatic colorimetric determination of H₂O₂.Vanadium oxide nanostructures are known for their redox activity and layered structures, making V₄O₇ a valuable material for sensing applications. The characterization of the prepared sample was done using XPS, XRD, Raman spectroscopy, and SEM techniques. The V₄O₇ microcube showed a rapid response to H₂O₂ through direct color change without the need for peroxidase enzymes or TMB. Upon exposure to H₂O₂, the mixed valence V₄O₇ oxidized to produce V₂O₅, enabling sensitive detection of H₂O₂. The V₄O₇ sensing system exhibited a wide linear response range from 0.025 to 300 µM with a low detection limit of 7.6 nM for H₂O₂ detection. When combined with glucose oxidase, the system could detect glucose levels as low as 18 nM within a linear range of 0.05 µM to 300 µM. The proposed sensor demonstrated high selectivity and robust potential for sensing H₂O₂ in biological samples. The system offers advantages such as fast response, simple operation, naked-eye observation, and cost-effectiveness. The novel sensing system holds promise for visual detection in H₂O₂ diagnostic clinics, highlighting its potential for practical applications in healthcare settings.