A flexible visual detection of calcium peroxide in flour employing enhanced catalytic activity of heterogeneous catalysts binary copper trapped silica-layered magnetite nanozyme

Herein, a novel heterogeneous nanozyme with peroxidase (POD)-like activity was conducted to achieve ultra -sensitive visual detection of calcium peroxide (CaO2) in flour by the assembly of binary copper-trapped meso-porous silica layer coated magnetite nanoparticles (Fe3O4 @SiO2 @CuO NPs). The prepared nanozymes were characterized using HRTEM, SEM, FT-IR, XRD, DLS, and EIS, which displayed a dispersed core-shell structure with a uniform diameter of approximately 100 nm. The nanozymes exhibited remarkable and stable POD-like activity in a wide range of pH values, incubation temperature, and reaction time, and the optimum catalytic activity was obtained at pH 3.6, 37 degrees C, and 10 min. The quantification range of CaO2 of this method is 0.1-5 mM with a limit as low as 5.6 x 10-3 mM, and it is not affected by multiple interferences. In conclusion, this detection method is sensitive, stable, low-cost, and simple to operate, so it has broad application prospects in the detection of food additives such as CaO2.

Automated summary

In this study, a novel heterogeneous nanozyme was developed for ultra-sensitive visual detection of calcium peroxide in flour. The nanozyme exhibited remarkable and stable peroxidase-like activity and had a wide range of applications in the detection of food additives. The detection method was sensitive, stable, low-cost, and simple to operate.