Visualization of Tocopherol Acetate Absorbed Inside Laminated Films by a Matrix-assisted Laser Desorption/Ionization-imaging Mass Spectrometry

The aim of this study was to visualize the sorption of tocopherol acetate as a penetrant into polymer films. A matrix-assisted laser desorption/ionization-imaging mass spectrometry (MALDI-IMS) technique was used to visualize the distribution of tocopherol acetate in films during the migration process. A phytic acid-aided MALDI-IMS using 2',4',6'-trihydroxyacetophenone as a matrix allowed us to successfully visualize the absorbed tocopherol acetate in both ethylene-vinyl acetate copolymer (EVA) and low-density polyethylene (LDPE) films after 1 week-storage of tocopherol acetate at 40 degrees C. The IMS technique allowed us to also visualize the actual distribution of tocopherol acetate inside the EVA/barrier/EVA laminated films, in which tocopherol acetate sorption was blocked at the barrier layer.