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 initiating role, they allow for the rapid hardening of formulations. However, some photoinitiators, such as benzophenone, ITX (isopropylthioxanthone), and BDK (benzildimethyl ketal), are monitored due to their potential toxic effects and their ability to migrate into food.

Therefore, the dosage of photoinitiators is an essential step to ensure the conformity of materials in contact with food, to assess the risks associated with migration and to guarantee the safety of products placed on the market.

Analytical methods

The analysis relies primarily 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 concentrations in the ppb range.
• GC-MS for the analysis of volatile or semi-volatile compounds present in complex matrices.

These approaches make it possible to detect a wide spectrum of photoinitiators and to evaluate their migration under real or simulated conditions.

Affected matrices

The dosage applies to various industrial and consumer matrices:

• Inks and varnishes used on food packaging
• Glues and adhesives
• Polymer 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 comply with regulatory thresholds and do not present risks to consumers.
• Polymeric materials : checking the conformity of resins and adhesives used in manufacturing processes.
• REACH compliance and cosmetics regulation : meeting regulatory obligations related to the use and monitoring of chemical substances.

Additional analyses

Photoinitiator assays can be supplemented by other tests available in the YesWeLab catalogue:

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

Regulations and quality issues

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

Controlling photoinitiators allows manufacturers to guarantee the safety of their products, anticipate the risks of non-compliance and strengthen the confidence of consumers and regulatory 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, numerous manufacturers and distributors have trusted us to secure their analyses and ensure the conformity of their materials.