Overview - ISO 2871-1:2010 (cationic-active matter, high-molecular-mass)
ISO 2871-1:2010 specifies a laboratory method for determining the content of high-molecular-mass cationic-active matter in detergents and surface-active products. The standard covers long-chain cationic surfactants such as quaternary ammonium compounds (e.g., distearyl-dimethyl-ammonium chlorides) and certain imidazoline salts when two alkyl groups each contain 10 or more carbon atoms. The procedure is applicable to solids and aqueous solutions where the relative molecular mass of the cationic-active material is known. The method is not applicable when anionic surface-active agents are present.
Key topics and technical requirements
- Analytical principle: Direct two-phase titration - titration of a sodium lauryl sulfate standard solution with the test sample using the two-phase titration procedure described in ISO 2271.
- Primary reagents: chloroform, propan-2-ol (isopropanol), a standard sodium lauryl sulfate solution, and a mixed indicator solution.
- Apparatus: routine laboratory glassware plus class A burette (25 ml) and a 1 000 ml one-mark volumetric flask as specified by ISO 385 and ISO 1042.
- Sample preparation and sampling: laboratory sample preparation per ISO 607; test portion chosen to give a titration volume typically 10–20 ml.
- Interferences:
- Method is invalid in the presence of anionic surfactants.
- Low-molecular-mass sulfonates (toluene/xylene sulfonates) do not interfere up to ~15% (mass fraction).
- Non-ionic surfactants, soap, urea, EDTA salts and common inorganic detergents additives generally do not interfere.
- Bleaching agents other than perborate must be destroyed before analysis.
- Results and precision:
- Content is calculated from the titration volume, sodium lauryl sulfate concentration and the known molecular mass of the cationic-active matter and expressed as a percentage by mass.
- Repeatability: difference between duplicate determinations by one analyst should not exceed 1.5% of the mean.
- Reproducibility between laboratories should not exceed 3% of the mean.
Practical applications and users
- Chemical laboratories in detergent and personal-care product manufacturing for quality control and formulation verification.
- Regulatory and compliance testing where accurate quantification of quaternary ammonium and high-mass cationic surfactants is required.
- R&D groups developing cationic surfactant products or formulations that require validated analytical methods.
- Contract testing labs offering surfactant content analysis to manufacturers and brand owners.
Related standards
- ISO 2271: two-phase titration procedure (anionic-active matter determination) - referenced for titration technique.
- ISO 2871-2: determination of low-molecular-mass cationic-active matter (200–500).
- ISO 607 (sampling), ISO 385 (burettes), ISO 1042 (volumetric flasks) - normative references for equipment and sampling.
Keywords: ISO 2871-1:2010, cationic-active matter, high-molecular-mass, detergents, two-phase titration, sodium lauryl sulfate, quaternary ammonium.