Mass spectrometric determination of photolytic decomposition products of UV-photoinitiators and migration studies of UV-photoinitiators and decomposition products in food packaging

Joseph B. Scarsella
Resins in inks, coatings, and adhesives in food packaging are increasingly cured by UV radiation of photo-initiators (PI's) with minimal energy requirements and without environmentally unfriendly solvents. When exposed to UV light, PI's produce free radicals that catalyze polymerization of reactive monomers and pre-polymers into resins. PI's and their photolytic decomposition products do not polymerize during curing but remain as residuals that can migrate into foods stored therein, becoming
more » ... herein, becoming unintentional food additives. As interest in additive toxicity has increased, food safety organizations worldwide have developed regulations to monitor migration of these substances from food packaging. While intact PI's have been investigated, research on formation and migration of PI photolytic decomposition products is sparse.This research characterized and quantified decomposition products of twenty-four PI's commonly used in food packaging. UV-photoinitiators were applied as films onto aluminum foil disks, UV-irradiated using an energy level representing the upper limit typically used in commercial production (125-150 millijoules), and extracted from the foil. Structure and contents of migrating compounds were determined by gas chromatography-mass spectrometry (GC-MS) and direct mass spectrometry, and tentative mechanisms of formation were proposed. Non-irradiated photoinitiator standards were analyzed as controls.In total, 107 photolytic decomposition products were identified, 93 of which have not been previously reported as photolytic decomposition products of UV-photoinitiators. This compilation of PI decomposition products will aid industry in the tracing of the sources of compounds identified in migration testing of food packaging materials.To assess the frequency and extent of migration of PI's and photolytic decomposition products in actual products, migration data from 258 UV-cure food packaging samples analyzed in previous studies were re-examined. Migration of PI's or their photolytic decomposition produ [...]
doi:10.7282/t3-380j-r669 fatcat:s6fwfibwyvdfzmw2n4vemlrbgu