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.

To investigate effect of ultraviolet (UV) irradiation on the properties of poly (butyleneadipate-co-terephthalate) (PBAT), the properties of PBAT/nano-ZnO and PBAT/nano-TiO₂ composite films subjected and not subjected to UV irradiation, and the migration of nano-components from them to 3 g/100 mL acetic acid were studied. Meanwhile, the composite films were characterized by attenuated total reflection Fourier transformed infrared (ATR-FTIR) spectroscopy, field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). The results showed that the addition of each nanoparticle had little effect on the barrier performance of the composite film without UV irradiation. With the addition of nano-ZnO, the tensile strength of the composite film decreased by 22.88%-40.99%, the elongation at break decreased to 86.07%-90.98% of that of pure PBAT films, and the maximum migration of nano-ZnO was 11.82 mg/kg. The addition of nano-TiO₂ had little effect on the tensile strength, but decreased the elongation at break to 73.48%-87.18% of that of pure PBAT films, and no migration of nano-TiO₂ was observed (the detection limit of the method used was 0.009 mg/kg). With an increase in UV irradiation time, the elongation at break and tensile strength of the composite films decreased gradually, but the mechanical properties of the PBAT/nano-ZnO films decreased less than those of the pure PBAT and PBAT/nano-TiO₂ films at the same irradiation time. After two days of UV irradiation, the oxygen permeability coefficient of the composite films increased significantly (P < 0.05), while the moisture permeability coefficient changed little. The maximum migration of nano-ZnO was 16.66 mg/kg, whereas no migration of nano-TiO₂ was detected. The ester bond of the composite films was broken, the crystallinity reduced, and the surface became rough, with holes in it. We concluded that UV irradiation destroys the structure of PBAT composite film and degrades its properties. Nano ZnO can inhibit the decline of the mechanical properties of PBAT composite film to a certain extent, but its migration increases gradually.

The migration of the antioxidant Irgafos168 and its degradation products from poly(butyleneadipate-co-terephthalate)/polylactic acid (PBAT/PLA) composite films into the fatty food simulant isooctane under different working conditions (ultraviolet (UV), high humidity and salt atmosphere) was studied by gas chromatography-mass spectroscopy (GC-MS), and the aging degree of composite films under each condition was investigated in terms of their mechanical properties and infrared characteristics. The results showed that the degradation of PBAT/PLA composite films was greatly affected by UV and high humidity conditions. After two days of UV exposure, 60 days of high humidity exposure and 40 days of salt spray exposure, the tensile strength of the composite films decreased by 61.1%, 41.6% and 35.9% to 10, 15 and 17 MPa, respectively, and the elongation at break decreased by 93.5%, 34.1% and 21.5%, respectively. The antioxidant’s concentration had no significant effect on the properties of the composite films (P > 0.05). The migration of Irgafos168 and its degradation products was positively correlated with their initial levels in the composite films. The migration of Irgafos168 from the untreated composite film was the highest (85.39 mg/kg). The content of Irgafos168’s degradation products in the composite films increased with aging, the major one being tri(2,4-di-tert-butylphenyl) phosphate, which was produced in the largest amounts under UV conditions, and the migration of tri(2,4-di-tert-butylphenyl) phosphate was 3.04-99.50 mg/kg. The migration of the substances could be affected by temperature, their initial contents and the aging degree of the composite films.

A method was developed for the simultaneous determination of the residues and migration of 18 polycyclic aromatic hydrocarbons (PAHs) in food contact rubber by gas chromatography-mass spectrometry (GC-MS). The rubber extract was cleaned up by solid phase extraction (SPE) with a silica gel column. The migration solution was extracted with hexane, separated on a DB-EUPAH column (60 m × 250 μm, 0.25 μm), detected in the selective ion monitoring (SIM) mode, and quantified by an internal standard method. The results showed that good chromatographic separation of the 18 PAHs was achieved. The calibration curves showed good linearity in the concentration range of 0.05–0.5 mg/L. The limits of detection (LOD) were less than 0.01 mg/L, and the limits of quantification (LOQ) were less than 0.05 mg/L. The average recoveries for PAHs residues and migration at three spiked levels ranged from 61.3% to 102.2%, and the relative standard deviations (RSDs, n = 6) were 0.5%–9.1%. A total of 16 PAHs were detected in 10 of the 34 batches of food contact rubber tested with total residues ranging from 0.24 to 16.97 mg/kg. No PAHs were found to be migrated from the rubber to 4%acetic acid and 10% ethanol at different experimental temperatures. Many PAHs were found to be migrated to 50% ethanol as a food simulant. The number of PAHs migrated increased with an increase in temperature, and the rate and amount of migration increased significantly. The safety problems caused by the residues of PAHs in food contact rubber and their migration to foods cannot be neglected.