Determination of low concentrations of glucose through colorimetric analysis using CoFe2O4 magnetic catalyst and SAT-3

Natural enzyme mimics have attracted attention as alternatives to natural peroxidases. Among these, magnetic nanoparticles, especially ferrites, have attracted attention because of their unique electronic and physical structures, which are expected to be applied in various fields, including high-frequency magnetic materials, biomaterials, gas sensors, and semiconductor photocatalysts. The structural properties of the synthesized catalysts were investigated using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The prepared CoFe2O4 exhibited a spinel ferrite structure and formed a wood-flake-like bulk structure. In this study, magnetic CoFe2O4 was prepared using a precipitation method as a natural enzyme mimetic. CoFe2O4 showed excellent peroxidase-like activity, as demonstrated by the Michaelis–Menten constant (Km) and the maximum velocity (Vmax). The linear ranges of the calibration curves for H2O2 and glucose were in the range of 0–500 µM, and the detection limits were 1.83 and 5.91 µM, respectively. This analytical method was applied for the determination of glucose in human serum, and the results were satisfactory and consistent with certified values. The performance of this sensor was comparable to or superior to those of several other sensors commonly used for glucose analysis, indicating that its practical application is feasible.