Abstract:In this work，as calcium peroxide （CaO2）can react with sulfuric acid to produce hydrogen peroxide（H2O2）and H2O2 can cause rapid oxidation and chromogenesis in quaternary amine[4，4'-（p-dimethylamino）-diphenylmethane]by using KI as the sensitizer and methanobactin （Mb）mimic enzyme as the catalyst，a rapid and simple mimic enzyme-catalyzed colorimetry for the determination of CaO2 in wheat flour was established after the absorbance can be detected at 462 nm.The effects of Mb-Cu concentration，quaternary amine content，KI content，reaction temperature，pH value and reaction time on chromogenic reaction were investigated.The results showed that when the concentration of Mb-Cu was 4.5×10-5 mol/L，quaternary amine content was 60 μL，KI content was 12 μL，the reaction temperature was 50 ℃，and the detection time was 10 min，CaO2 concentration at 0-10 mg/L had a linear correlation with the absorbance at 462 nm，and the linear equation was y=0.078 1x+0.019 6，with a correlation coefficient（R2）of 0.997 6.The limit of detection（LOD）of this method was 1.82×10-2 mg/L （equivalent to 2.25 mg/kg wheat flour），the average recovery rate for spiked standards was 99.21%-100.35%and the relative standard deviation （RSD）was 0.31%-1.22%.This method is rapid and accurate，and thus it can be used for the determination of CaO2 in wheat flour.