Identification of unknown compounds from polyester cans coatings that may potentially migrate into food or food simulants

Abstract

Cross-linked polyester resins are being introduced into the market as alternatives to epoxy resins as coatings for metal food cans. Identification of potential migrants, from these coatings into food, is a significant analytical challenge due to the diversity of substances employed in the manufacture of the coatings. However, such identification is required to assess migration from the can coating into the food and quantify dietary exposure. Polyester can coatings were extracted with acetonitrile at 40°C for 24h and the extracts were analyzed by a variety of analytical techniques, including GC-MS, HPLC-DAD/MS, HPLC-DAD/CAD and UHPL C-HRMS. Twenty nine non-volatile oligomers were tentatively identified using retention times, UV spectra, and accurate mass measurements. Identified oligomers suggest the coating in use for food cans is a polyester coating and is mainly based on the monomers isophthalic acid, terephthalic acid and nadic acid. To give confidence in the identification, one of the tentatively identified oligomer was synthetized and analyzed by (13)C and (1)H NMR and UHPL C-HRMS. The NMR and HRMS results, confirmed the presence of this compound in the can extracts. Finally, to determine if rapid, direct detection of the oligomers was practical, the coatings were analyzed by DART-HRMS. Twenty three out of the 29 oligomers were identified in the coating by direct measurement with DART-HRMS in few minutes.

Food packaging simulant failure mechanisms in next generation steel packaging

“…This work is further evidenced by Oldring et al who worked on a model to estimate BPA-diglycidyl ether exposure, concluding that exposure for UK consumers was well below the tolerable daily intake for all derivatives. 17 With BPA non-intent (BPANI), migration studies have been carried out on coatings of similar chemistry, 18,19 as is common with all new coating formulations, with a multitude of analytical techniques used such as gas chromatography and mass spectrometry. 20 While these methods of interaction are relatively well reported, the effect of the simulant solution/foodstuff on the adhesion of a coating to the substrate, or the substrate itself post-retort, has not been reported in depth.…”

An overview of chemical contaminants and other undesirable chemicals in alcoholic beverages and strategies for analysis

“…Epoxy‐based resins currently dominate the market for can coatings, occupying an estimated 95% of market shares as of 2013 (Geueke, 2016). The most common type is synthesized with bisphenol A (BPA) and epichlorohydrin to form bisphenol A diglycidyl ether epoxy resins, though epoxy resin blends containing amines, acrylates, anhydrides, or phenolics are also options on the market (Geueke, 2016; Paseiro‐Cerrato, MacMahon, Ridge, Noonan, & Begley, 2016). Toxicological concerns and consumer backlash have spurred a search for alternatives to BPA, with acrylic and polyester materials being potential replacements and coatings composed of polyolefins or non‐BPA epoxies currently under development (Geueke, 2016).…”

Migration studies and chemical characterization of low molecular weight cyclic polyester oligomers from food packaging lamination adhesives

“…The identified migrants were mostly derived from diols, namely, diethylene glycol (DEG), ethylene glycol (EG), and neopentyl glycol (NPG), and diacids like adipic acid (AA), isophthalic acid (IPA), and phthalic acid (PA). Several cyclic oligoesters also have been reported from migration studies of polyester‐based can coatings, bottles, and trays . Though the available data on cyclic oligoesters are not exhaustive, all previously conducted studies indicate that a wide variety of cyclic oligoesters are pervasive migrants from polyester‐PU or polyester polyol‐PU packaging materials.…”

“…Several cyclic oligoesters also have been reported from migration studies of polyester-based can coatings, bottles, and trays. 15,[21][22][23][24][25] Though the available data on cyclic oligoesters are not exhaustive, all previously conducted studies indicate that a wide variety of cyclic oligoesters are pervasive migrants from polyester-PU or polyester polyol-PU packaging materials.…”