Optimization and Validation of Ultraviolet-Visible Spectrophotometric Method for Determination of Potassium Permanganate Consumption for Migrants from Food Contact Rubber

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 0.00574 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 0.99891. 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.