Untargeted screening of NIAS and cyclic oligomers migrating from virgin and recycled polyethylene terephthalate (PET) food trays

Polyethylene terephthalate is considered one of the most used and approved recycled plastic polymer as food contact materials (FCM); however, the fundamental details arising from the recycled content of PET trays in relation to processing conditions or extent of recycling are not well understood. In the present work, the presence and migration of different series of PET cyclic oligomers from industrially recycled trays were investigated using official food simulant D1 at 40 degrees C for 10 days. The trays were produced in two different facilities, using different extrusion processing technology, namely single and twin-screw extruder. Tested food packaging trays were produced from different ratios of virgin (vPET) and recycled PET (rPET), varying from 0% up to 100% w/w content. Analysis of the trays using MALDI-TOF-MS revealed a decrease in the molecular weight distribution (Mw) in rPET compared to virgin PET plastic. Untargeted screening with UHPLC-QTOF-MS, revealed the presence and migration of several intentionally added substances (IAS) as well as non-intentionally added substances (NIAS). The results demonstrated differences of the cyclic oligomers migration into the selected food simulant, depending on the rPET/vPET ratios as well as among the applied extrusion technology applied. Following multivariate analysis, marker compounds found to be benzyl butyl phthalate (BBP), butyl lactate, dodecenamide, 2-methyl-1,3-dioxolane, PET 2nd series cyclic dimer as well as PET 1st series cyclic dimer can be considered as marker compounds.