Residual peroxide analysis

Peroxides are oxidizing agents that can be used as initiators in polymerization processes or form naturally through oxidative degradation. Residual peroxides in cosmetic polymers, resins, oils, or emulsions can alter the stability of finished products, cause undesirable side reactions, or affect the functional properties of materials.

The determination of residual peroxides is therefore essential to assess the oxidative stability of formulations, to verify the end of reaction in industrial processes or to control the conformity of products according to safety and quality standards.

Analytical methods
The analysis of residual peroxides relies on various validated approaches:

• Iodometric titration : a classic and widely used method, measuring the oxidizing capacity of peroxides by reduction of iodine.
• Peroxide value method : used in food or cosmetic oils and fats, it allows monitoring the degree of oxidation and assessing rancidity.
• UV-Vis spectrophotometry : when applied to certain formulations, it offers increased sensitivity for liquid or complex matrices.

These methods can be adapted according to the nature of the product being analyzed and the applicable standards.

Matrices concerned:
Residual peroxide analysis applies to a wide range of products and materials:

• Synthetic polymers and resins produced by polymerization processes
• Cosmetic emulsions, creams and lotions
• Vegetable or mineral oils used in food or cosmetics
• Inks, varnishes or adhesives containing oxidizing agents

Industrial applications

• Packaging and polymeric materials : check the stability of polymers and detect residues that may interfere with migration into food.
• Cosmetics : controlling the stability of emulsions and lipid-rich formulations, limiting the risks of oxidation and ensuring consumer safety.
• Agri-food : monitor the freshness and quality of vegetable oils, fats and butters by following their peroxide value.
• Industrial processes : validating the end of the reaction during the manufacture of polymers or resins.

Further analyses:
Peroxide analysis can be integrated into a broader analytical strategy:

• Acid value measurement to assess free fatty acid content and monitor hydrolysis.
• Determination of the specific peroxide value of oils and greases.
• Monomer analysis to identify residues of starting substances in polymers.
• Global migration tests to assess the safety of packaging in contact with food.

Regulations and Quality Challenges:
In the food industry, the measurement of residual peroxides is one of the quality controls required for oils and fats to prevent oxidation and ensure compliance with international standards. In the field of packaging and polymers, this analysis demonstrates material stability, anticipates degradation risks, and meets the requirements of Regulation (EU) No 10/2011 for materials intended to come into contact with food.

In cosmetics, monitoring peroxides is a key indicator to ensure the durability of formulations and limit the occurrence of oxidative reactions that could impair the performance or safety of the product.

YesWeLab's expertise:
YesWeLab collaborates with a network of ISO 17025 accredited laboratories, selected for their expertise in the analysis of polymers, oils, and cosmetic formulations. Depending on your needs, we identify the most suitable method and the most competent laboratory to guarantee reliable, compliant, and rapid results.

Our digital platform simplifies analysis management by centralizing your quote requests, sample tracking, and access to final reports. Since 2020, numerous manufacturers and distributors have entrusted us with the management of their analytical testing.