Polyethylene glycol (PEG) dosage

Polyethylene glycol (PEG) analysis allows for the determination of the concentration of this hydrophilic polymer in cosmetic, pharmaceutical, chemical, or technical products. PEG is a family of polyethers widely used for its emollient, solubilizing, and stabilizing properties, but its presence must be controlled due to certain regulatory restrictions and natural certification requirements.

The analysis is performed by HPLC (high-performance liquid chromatography) or GC-FID (gas chromatography with flame ionization detection), depending on the matrix and molecular size of the PEG to be quantified.

Polyethylene glycol: a multifunctional polymer

Polyethylene glycol (PEG) is a polymer formed by polymerization of ethylene oxide. Its general formula HO–(CH₂–CH₂–O)n–H varies according to the number of repeating units, giving products ranging from viscous liquids to solid waxes.

Widely used in the cosmetics and pharmaceutical industries, PEG fulfills several functions:

• moisturizing and emollient agent,
• solubilizer for lipophilic active ingredients,
• emulsion stabilizer,
• active ingredient support in drug formulations,
• plasticizer and binder in solid products.

However, some environmental charters (COSMOS, Ecocert, Natrue) restrict or prohibit petrochemical-derived PEGs because their manufacturing process involves the use of potentially toxic substances such as ethylene oxide or 1,4-dioxane. Therefore, PEG content measurement is an essential tool for ensuring regulatory compliance and formula transparency.

Objectives and benefits of PEG assay

The dosage of polyethylene glycol addresses several issues:

• verify the conformity of products with ecological and organic specifications (COSMOS, Ecocert, Natrue),
• to control PEG concentrations in cosmetic, pharmaceutical or chemical products,
• to evaluate the purity and stability of formulations containing polyethoxylated derivatives,
• detect the presence of residual PEG in products labeled “PEG-free”,
• monitor the quality of the raw materials used in the formulations.

This analysis applies to various matrices: creams, gels, shampoos, lotions, toothpastes, balms, pharmaceutical excipients or technical formulations.

Analytical methods used

PEG quantification can be performed using several analytical techniques depending on the complexity of the matrix:

• HPLC (high-performance liquid chromatography) : reference method for high molecular weight PEGs, allowing efficient separation of polymer chains and precise quantification.
• GC-FID (gas chromatography with flame ionization detection) : used for volatile or low molecular weight PEGs, offering good sensitivity and reproducibility.
• Infrared spectroscopy (FTIR) : used to confirm the presence of characteristic ethoxylated groups in polymeric or cosmetic matrices.
• MALDI-TOF : in some cases, this mass spectrometry technique allows obtaining a detailed distribution of the molecular masses of PEGs.

YesWeLab selects the most suitable method based on the nature of the product, the range of polymer masses and the customer's requirements.

For additional controls on raw materials or finished products, this analysis can be combined with the determination of propylene glycol , the determination of sodium lauryl sulfate (SLS), or the analysis of non-ionic surfactants.

Industrial and regulatory applications

PEG dosage is essential for many sectors:

• Cosmetics : PEG testing ensures compliance with Regulation (EC) No. 1223/2009 and ecolabels. Manufacturers of natural cosmetics use this test to demonstrate the absence of synthetic PEGs in their formulas.
• Pharmaceuticals : PEGs are used as excipients, solvents, or carriers for active ingredients. Assays allow for validation of the concentration and pharmaceutical quality of the polymer used.
• Chemistry and industrial formulation : the test allows the characterization of PEG residues in formulations of paints, adhesives or detergent products.
• Environment : In the context of industrial discharge analyses, the quantification of PEG can contribute to assessing the biodegradability of effluents.

The results obtained confirm the conformity of the products with regulatory standards and quality standards imposed by ecological certifications and ISO standards.

Carrying out analyses at YesWeLab

YesWeLab entrusts the PEG assay to partner laboratories specializing in the analysis of polymers and cosmetic formulations. These laboratories have high-precision chromatographic equipment (HPLC, GC-FID, GC-MS), enabling the detection and quantification of PEGs at low concentrations, while guaranteeing the traceability of results.

The analyses are conducted in accordance with ISO 17025 and COFRAC standards. The protocols are adapted to the specific requirements of the COSMOS and Ecocert specifications.

The YesWeLab scientific team assists each client in defining the most appropriate method for their product and regulatory objective. Thanks to the YesWeLab digital platform, ordering, tracking analyses, and receiving reports are all simple and straightforward.

Since 2020, YesWeLab has been collaborating with numerous cosmetic manufacturers and formulation laboratories for quality control and certification of natural and ecological products.

Technical data

• Methods: HPLC, GC-FID, FTIR
• Expertise: Physicochemical
• Sectors of activity: Cosmetics, pharmaceuticals, chemicals, technical formulation
• Measured parameters: Total polyethylene glycol (PEG) and polyethoxylated derivatives
• Normative references: ISO 17025, Regulation (EC) No 1223/2009, COSMOS and Ecocert standards

For any specific request, contact our team to obtain a personalized quote and analytical recommendations tailored to your formulations and quality standards.