Overview
EN ISO 8799:2009 (ISO 8799:2009) defines a laboratory method for determining the content of unsulfated matter in commercial, neutralized sulfated surfactants - specifically sulfated ethoxylated alcohols and alkylphenols (also called alkyl oxyethylene sulfates or alkylphenol oxyethylene sulfates) containing on average no more than 20 oxyethylene groups per molecule. The standard is intended for routine quality control of anionic surfactant products and specifies sample preparation, resin treatment, separation, and calculation procedures.
Key topics and technical requirements
- Principle: Unsulfated matter is separated from the sulfated surfactant by passing a methanolic solution of the sample through a mixed-bed ion-exchange column (mixture of cation- and anion-exchange resins). The eluate is evaporated and the residue weighed to give the unsulfated content.
- Reagents & materials: Uses analytical-grade methanol, HCl (~1 mol/l), NaOH (~2 mol/l), cation-exchange resin (polystyrene sulfonic acid, H+ form) and anion-exchange resin (polystyrene quaternary ammonium, Cl– form). Water meeting ISO 3696 is required.
- Apparatus: Typical lab equipment plus a rotary evaporator, open glass ion-exchange column (25 mm × 200 mm), and controlled water bath (25–40 °C).
- Resin preparation: Detailed clean-up and conditioning steps for both anion and cation resins (swelling, alkali/acid washes, methanol rinses) and mixing equal volumes to form a 50–60 ml packed bed.
- Procedure essentials: Test portion equivalent to 5 mmol anionic-active matter dissolved in 50 ml methanol, filtration over the mixed-bed column, controlled flow rates (around 2–3 ml/min), extensive methanol washing, rotary evaporation of eluate, drying to constant mass (±3 mg).
- Quality checks: Verification of ion-exchange completeness by titrating residue for anionic-active matter (ISO 2271 or EN 14480). If >0.005 mmol remains, procedure must be repeated or flow/wash adjusted.
- Calculation & precision: Unsulfated content reported as mass percent (residue mass / test portion mass × 100). The standard includes repeatability and reproducibility guidance from interlaboratory data.
Applications and users
- Quality control laboratories in surfactant and detergent manufacturing
- Incoming material testing at chemical suppliers and formulation companies
- R&D groups assessing sulfation process efficiency or product purity
- Regulatory and compliance testing where specification limits for unsulfated matter are required
Related standards
- ISO 2271 - determination of anionic-active matter (two-phase titration)
- EN 14480 - potentiometric two-phase titration method for anionic surfactants
- ISO 607 - sample division for surface active agents
- ISO 3696 - water for analytical laboratory use
Keywords: EN ISO 8799:2009, ISO 8799:2009, unsulfated matter, sulfated ethoxylated alcohols, alkylphenols, ion-exchange separation, surfactant quality control, anionic-active matter.