Oligomers: Hidden sources of bisphenol A from reusable food contact materials

Abstract

A recent European Regulation further restricted the use of bisphenol A in food-contact materials, reducing its limit of migration. However, all analytical systems of control are aimed at identifying and quantifying the molecules of this monomer without taking in consideration the possible presence of its oligomers, species originating from material degradation and able to follow an in-vivo hydrolysis providing bisphenol A generation. Thus, the presence of oligomers of polycarbonate deriving by unreacted species or polymer degradation can be considered a hidden source of several bisphenol A units, that remains outside the control of legislation and should be considered of high concern. This work was focused on the identification and the description of kinetics of release of different molecules migrating from polycarbonate food contact materials to simulants and to a model food sample such as melted chocolate. Analyses were performed by UHPLC system coupled to a Q-Exactive mass spectrometer. Targeted and untargeted analysis through data dependent acquisition mode allowed to detect the occurrence of several species deriving from polycarbonate, and permitted to investigate the polymer degradation pattern and explore the correlation of the recorded amounts of each product with age, hours of usage, and washing cycles of the plastic items.

Keywords: Bisphenol A; Degradation products; Food contact material; Migration; Oligomers; Polycarbonate.