摘要：A modified method for the determination of residual hydrogen peroxide (H2O2) in foods by oxygen electrode was developed. H2O2 content in the sample was calculated from the difference between H2O2 values obtained from the sample with and without catalase treatment. H2O2 was extracted from the sample by dipping with acidic extractant (sulfuric acid containing zinc sulfate and potassium bromate) in ice-water. The mixture of the extractant and the sample was adjusted to pH 6-8 with sodium hydroxide solution and phosphate buffer after the extraction. H2O2 content in the filtered extract was determined with oxygen electrode according to the Toyoda's method. The recoveries of H2O2 added to 14 kinds of commercial foods at levels of 1 and 5 μg/g were in the range of 62.3-102.9 and 89.8-100.2%, respectively. The recoveries from 8 kinds of foods by the modified method were higher than those by the Toyoda's method. H2O2 contents in 14 kinds of comercial foods were not detected except yogurt (2.49 μg/g). H2O2 contents obtained from 11 kinds of foods by the modified method were lower than those by the Toyoda's method. Residual H2O2 contents in 6 kinds of foods treated with H2O2 were determined. H2O2 contents obtained from the 2 kinds of foods by the modified method were higher than those by the Toyoda's method, and H2O2 contents obtained from 4 kinds of foods by the two methods were similar. These results suggested that the modified method is more suitable than the Toyoda's method for the determination of residual H2O2 in foods treated with H2O2.
