Kinetic Study of Bisphenol A Migration from Low-Density Polyethylene Films into Food Simulants

Migration testing of bisphenol A (BPA) from low-density polyethylene (LDPE) into food simulants was performed as a function of three factors: temperature, initial BPA concentration, and food simulant type. An HPLCUV method was applied to measure the amount of BPA that migrated into the solvents. The migration process was described by Ficks diffusion equation, and the migration parameters such as the diffusion coefficient (D) were derived from the equation. D values ranged from 10(-10) to 10(-8) cm(-2) s(-1) under different migration conditions. Statistical analysis showed that the single factors had significant effects on D, but among the interaction effects only the temperature-simulant interaction was significant. The dependence of D on temperature followed an Arrhenius-type relationship, with the activation energy (E-a) ranging from 112.8 +/- 1.6 kJ mol(-1) to 128.9 +/- 4.3 kJ mol(-1) for the three food simulants. An exponential relationship was found between the diffusion coefficient and initial BPA concentration for each food simulant. BPA migration into different food simulants was influenced by the affinity between the polymer and the solvent, and better affinity may reduce the diffusion rate of BPA.