Spectrophotometric Determination of Amount of Hydrogen Peroxide Remained in Soaking Solution of Water-Soaked Foodstuffs

In a slightly acidic medium, brilliant green SF was oxidized by of ·OH free radical produced by the reaction between H2O2 and Fe(Ⅱ), leading to decrease in absorbance at its absorption maximum of 632 nm. Optimum conditions for the reaction were found as follows: ① time of reaction: 20 min; ② acidity of reaction medium: pH 3.0; ③ initial concentration of Fe(Ⅱ): 100 μmol·L-1; ④ temperature for the reaction: 25 ℃. Linear relationship between values of decrease in absorbance (ΔA) and concentration of H2O2 was kept in the range within 50 μmol·L-1 with detection limit (3s/k) of 0.25 μmol·L-1. On this base, a photometric method for determination of traces of H2O2 remained in the soaking solution of waterscaked foodstuffs was proposed. Three portions of soaking solutions were analyzed by the proposed method and recovery was tested by standard addition method. Values of recovery found were in the range of 91.0%-112%, with RSD′s (n=5) ranged from 1.9% to 2.5%.