Abstract: An analytical method for the determination of manganese dioxide (KMnO4) consumption for migrants from food contact rubber by ultraviolet-visible (UV-Vis) spectrophotometry was established. The reaction time, and the concentration of sulfuric acid (H2SO4) and KMnO4 were optimized, and the analytical figures of merit of the method were evaluated. Results showed that the concentrations of H2SO4 and KMnO4 in migrant aqueous solution with KMnO4 consumption of 1 mg/kg should exceed 0.1 and 0.005 74 mmol/L, respectively, and the optimal reaction time was 6 min. The detection wavelength was set at 525 nm. The KMnO4 standard solution exhibited good linearity in the range of 0.014–0.280 mmol/L, with a correlation coefficient (R2) of 0.998 91. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 6.8 × 10-4 and 2.0 × 10-3 mmol/L, respectively. F test and t test showed that the results of this method were not significantly different from those of the official redox titration method, and the relative standard deviation (RSD) was between 1.7% and 7.8%. The proposed method is useful for the analysis of KMnO4 consumption for migrants from food contact rubber in food quality control.

Key words: ultraviolet-visible spectrophotometry; food contact rubber; manganese dioxide consumption; optimization and method validation