Phenolic resins for can coatings: I. Phenol-based resole analysed by GC–MS, GC×GC, NPLC–GC and SEC

Phenolic resins (resoles) are used for curing expoxy and polyester coatings, e.g., for food cans. They consist of oligomeric materials prepared from phenols (phenol, cresol, tert.-butyl phenol), formaldehyde and butanol and are an analytical challenge because of the complexity of their composition. A phenol-based resole was selected for a first investigation of various analytical techniques: gas chromatography (GC)–mass spectrometry (MS), comprehensive two-dimensional GC (GC×GC), normal phase high-performance liquid chromatography (NPLC, primarily of interest for preseparation for GC analysis), and size exclusion chromatography (SEC). Mass spectra are discussed for some selected compounds and a list of spectra is added. GC×GC was the most powerful method for separating and visualizing the composition of the complex mixture, but the whole battery of methods might be needed to characterize resoles and to analyse their migration into food or food simulants.