Migration Studies of Food Packaging Using Modified Polyphenylene Oxide (MPPO) Solid Food Simulant

摘要

Modified Polyphenylene Oxide (MPPO), also known as TenaxRTM, is a porous adsorbent polymer widely used as trapping media for volatile and semi-volatile compounds in analytical chemistry procedures. It is also the recommended solid food simulant for migration testing of packaging materials in the European Union plastic Regulation No 10/2011. In the United States, FDA recommends only liquid simulants for migration testing. However, liquid simulants may not be appropriate in simulating solid foods because they may be ineffective at trapping volatile compounds and may exaggerate the migrant profiles. In addition, liquid simulants such as ethanol solutions and food oil may not be suitable for migration testing under microwave or high-temperature cooking conditions. On the other hand, current European MPPO conditioning procedures are time-consuming and the solvent extraction analysis technique is inadequate. The purpose of this study is to evaluate MPPO as a solid food simulant and compare its effectiveness to FDA-recommended liquid food simulants by gas chromatography-mass spectrometry (GC-MS) analysis. Firstly, we optimized the suggested procedures in EU regulation to develop a more effective, economical and timesaving technique for conditioning MPPO to be used as a food simulant. Secondly, we demonstrated that direct thermal desorption is a better way in comparison to solvent extraction for analyzing compounds trapped in MPPO. Finally, we evaluated MPPO in migration testing of 9 solid food packaging materials including UV and EB ink printed paperboard, laminated paper bag, water-based varnished tea tag, pizza box, microwavable paperboard, conventional ink printed lidding material, laminated microwavable sealant film, laminated plastic pouch, laminated sodium bicarbonate paper bag. We found that MPPO was more effective in studying the migration of volatiles and semi-volatiles than liquid simulants from all packaging materials tested. We also observed that liquid simulants tended to penetrate through paperboard materials and extract ink-borne migrants from the non-contact side of the packaging, and thus exaggerate the migration profiles. Furthermore, we proved that MPPO traps the chemicals by direct contact and gas phase transfer, which is the same mechanism of migration from food packaging into solid food. In addition, MPPO better fulfills the application needs of migration testing inside microwave oven than liquid food simulants.