Photoinitiator dosage

Photoinitiators are chemical molecules used to trigger polymerization under ultraviolet radiation. They are widely used in the manufacture of inks, varnishes, adhesives, resins, and materials for food packaging. Thanks to their triggering role, they enable rapid curing of formulations. However, some photoinitiators, such as benzophenone, ITX (isopropylthioxanthone), or BDK (benzildimethylketal), are monitored due to their potential toxic effects and their ability to migrate into foodstuffs.

The dosage of photoinitiators is therefore an essential step to ensure the conformity of materials for food contact, assess the risks linked to migration and guarantee the safety of products placed on the market.

Analytical methods

The analysis is mainly based on chromatography techniques coupled with mass spectrometry:

• HPLC or UPLC with UV or fluorescence detection for initial screening of photoinitiators.
• LC-MS/MS for targeted detection and precise quantification, even at ppb concentrations.
• GC-MS for the analysis of volatile or semi-volatile compounds present in complex matrices.

These approaches allow the detection of a broad spectrum of photoinitiators and the evaluation of their migration under real or simulated conditions.

Affected matrices

The dosage applies to different industrial and consumer matrices:

• Inks and varnishes used on food packaging
• Glues and adhesives
• Polymeric resins
• Plastic and multilayer materials
• Finished products intended to come into contact with foodstuffs

Industrial applications

• Packaging safety : check the migration of photoinitiators into foodstuffs and meet the requirements of Regulation (EU) No 10/2011.
• Quality control of inks and varnishes : ensuring that formulations meet regulatory thresholds and do not present risks to consumers.
• Polymeric materials : check the conformity of resins and glues used in manufacturing processes.
• REACH and cosmetics regulation compliance : meeting regulatory obligations related to the use and monitoring of chemical substances.

Additional analyses

The dosage of photoinitiators can be supplemented by other tests available in the YesWeLab catalog:

• NIAS assay , to identify unintentionally added substances that may migrate.
• Specific migration tests , essential for assessing the safety of food packaging.
• Monomer dosage , in order to control the presence of polymerization residues.
• Dosage of phthalates , other additives monitored in plastics and packaging.

Regulations and quality issues

Photoinitiators are under increased scrutiny in the European Union. Some compounds, such as benzophenone and ITX, have been reported to migrate into foodstuffs from printed packaging. Regulation (EU) No 10/2011 strictly regulates the use of these substances in food contact materials.

Photoinitiator control allows manufacturers to guarantee the safety of their products, anticipate risks of non-compliance and strengthen the confidence of consumers and control authorities.

YesWeLab expertise

YesWeLab relies on a network of ISO 17025-accredited laboratories, rigorously selected for their expertise in materials and packaging analysis. Each sample is directed to the most appropriate laboratory and method based on the matrix being studied, in order to obtain reliable results that comply with international standards.

Our digital platform simplifies the entire process: online quote requests, sample tracking, and quick access to analysis reports. Since 2020, many manufacturers and distributors have trusted us to secure their analyses and ensure the compliance of their materials.