Tentative identification of BADGE derivatives in epoxy type coatings in a model sample: a beverage can

Organic coatings have been applied to the inside surfaces of cans intended to come into contact with food and beverages. In general, polymeric coatings are complex formulations that may contain different components such as resins, crosslinking agents, catalysts, wetting agents, etc. The most widely used type of polymeric coating is epoxy, which is obtained by the condensation of epichlorohydrin and bisphenol A, which yields bisphenol A diglycidyl ether (BADGE). The resulting finished material may have starting substances such as monomers and additives, and also non-intentionally added substances that can potentially migrate from the food contact material into the food. In the present study, a beverage can, as a model sample, was evaluated. First, the internal surface was identified as epoxy-based coating using an infrared spectrometer with attenuated total reflectance. In the second part of the work, an acetonitrile extract of the can sample was obtained in order to tentatively identify potential BADGE derivatives using a non-targeted screening by liquid chromatography coupled to tandem mass spectrometry in positive and negative atmospheric pressure chemical ionization mode. Several BADGE derivatives could be tentatively identified comparing their characteristic m/z with a homemade database developed taking into account possible starting substances used in epoxy resins.