Analysis of specific migration of monomers and oligomers from polyethylene terephthalate bottles and trays according to the testing methods as prescribed in the legislation of the EU and Asian countries

Specific migration levels of monomers and oligomers in polyethylene terephthalate (PET) food containers were determined using HPLC according to the migration testing methods specified by the relevant legislations of the EU and Asian countries (e.g. Korea and Japan). The results of migration from PET bottles and trays using non-fatty simulants under the testing conditions (60 °C/0.5 h) of Asian countries indicated that the values of various monomers and oligomers (TPA, MHET, BHET, A2 group, A3 group, S2 group, S3 group, cyclic dimer, and cyclic trimer) were in between 0.0 and 0.58 μg dm−2. On the other hand, those obtained with the EU conditions (40 °C/10 days) were in the range of 0.0 to 0.94 μg dm−2. The specific migration values of monomers and oligomers into non-fatty simulants tended to be generally higher in testing under the EU conditions than under Asian conditions. Furthermore, when PET samples were tested for migration from fatty foods simulants using n-heptane (at 25 °C/1 h as per Asian conditions) or iso-octane (at 20 °C/48 h as per EU conditions), only cyclic trimer was detected at levels of 0.36 to 1.05 μg dm−2 and 0.05 to 0.55 μg dm−2, respectively. The use of 95% ethanol as an alternative fatty food simulant for the migration tests of PET would be inappropriate, since it might cause overestimated migration compared to the use of other simulants such as n-heptane and iso-octane.