Chromatographic Verification of Photoinitiator Specific Migration Limits in Printed Barrier Packaging
Chromatographic testing via LC-MS/MS verifies photoinitiator specific migration limits in printed barrier packaging to maintain compliance.
Photoinitiator Cleavage Products
Chemical Byproduct
Chemical compounds formed during the light induced curing of printing inks can persist in the dried film and pose a risk of contamination. These substances, known as photoinitiator cleavage products, are the fragments left behind after a photoinitiator molecule absorbs ultraviolet light and breaks apart. While the parent compound is the focus of regulatory lists, these resulting fragments can be more volatile and chemically active.
Migration Risk
Because they are often smaller than their parent molecules, photoinitiator cleavage products can diffuse rapidly through paperboard or polymer layers. This increased mobility allows them to migrate through the packaging wall and contaminate the food. This issue is particularly severe in printed food packaging that is stored for long periods under ambient temperatures, where the low molecular weight fragments slowly make their way to the food contact side.
Analytical Identification
Laboratories use sophisticated gas chromatography and mass spectrometry to identify these fragments in packaging extracts and food simulants. Identifying these substances requires specialized libraries because many cleavage products are not documented in standard chemical databases. Measuring the exact quantity of photoinitiator cleavage products ensures that the packaging complies with overall migration limits and does not affect the smell or taste of the food.
When a high level of fragments is found, the printing process must be adjusted to use different curing lamps or alternative ink formulations that generate fewer byproducts.