Characterization of Polyester Coatings Intended for Food Contact by Different Analytical Techniques and Migration Testing by LC-MSn

Abstract

Polymeric coating formulations may contain different components such as cross-linking agents, resins, lubricants, and solvents, among others. If the reaction process or curing conditions are not applied in a proper way, these components may remain unreacted in the polymeric network and could be released and migrate into foods. In this study, several polyester coatings intended for food contact were investigated. Firstly, Fourier-transform infrared spectroscopy with an attenuated total reflectance (ATR-FTIR) spectrometer and confocal Raman microscopy were used to identify the type of coating. Then, different techniques, including gas chromatography coupled to mass spectrometry (GC-MS) and analysis by matrix-assisted laser desorption coupled to time-of-flight mass spectrometry (MALDI-TOF-MS), among others, were used to investigate the potential volatile and non-volatile migrants. Moreover, migration assays were carried out to evaluate the presence of monomers and to tentatively identify possible oligomers below 1000 Da. The analyses were performed by liquid chromatography coupled to ion trap mass spectrometry (LC-MSn). Using the information collected from each analytical technique, it was possible to elucidate some of the starting substances used in the formulation of the polyester coatings analyzed in this study. In migration tests, several polyester oligomers were tentatively identified for which there is not toxicological data available and, therefore, no migration limits established to date.

Food and beverage can coatings: A review on chemical analysis, migration, and risk assessment

“…The technique allows a complete characterization of the coating by imaging the different layers. The novel approach has been successfully applied to characterize polyester‐based coatings for food contact (Lestido‐Cardama et al., 2022).…”

Clearing Properties Between Coconut Oil and Xylene in Histological Tissue Processing

“…25 It is used as a solvent in the manufacturing of chemicals, an ingredient in aviation fuel and gasoline, 26 and a feedstock in manufacturing various polymers, phthalic anhydride, isophthalic acid, terephthalic acid, and dimethyl terephthalate. 27 Xylene is the most recommended clearant due to properties such as its melting range (−47.87C to 13.26C). 28 It clears tissue rapidly (15-30 minutes) and is miscible with absolute alcohol 29 as well as paraffin.…”

“…25 It is used as a solvent in the manufacturing of chemicals, an ingredient in aviation fuel and gasoline, 26 and a feedstock in manufacturing various polymers, phthalic anhydride, isophthalic acid, terephthalic acid, and dimethyl terephthalate. 27…”

Oligoester Identification in the Inner Coatings of Metallic Cans by High-Pressure Liquid Chromatography–Mass Spectrometry with Cone Voltage-Induced Fragmentation

“…The determination of the structure of this kind of migrant is an area of research that has been recently widely developed in the field of food packaging materials and non-intentionally added substances; however, the reported data are definitely less numerous than those devoted to epoxy resin-derived migrants and requires further exploration. The vast majority of the reported polyester-derived migrants are cyclic oligoesters [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. The formation of cyclic oligoesters in higher amounts in comparison to their linear counterparts may be related to the conditions of the synthesis process, e.g., under high dilution conditions, intramolecular esterification may be statistically favored [ 13 , 24 ].…”