Overview
ISO 21257:2018 specifies a gas chromatography (GC) method for the determination of residual acrylonitrile and styrene monomers in polymer polyols used to produce polyurethane. The standard describes sample preparation, GC hardware and operating requirements, calibration procedures and result expression to support reliable measurement of these toxic residual monomers in polymer polyols.
Key topics and technical requirements
- Scope: Measurement of residual acrylonitrile and styrene monomer content in polymer polyols by GC.
- Analytical principle: Dissolve sample in a suitable solvent, analyse by GC with internal standardisation, and quantify monomers from peak areas using a calibration curve.
- Columns and injection: Supports both open tubular (OT/capillary) columns and packed columns; split or splitless injection is allowed. Two preparation methods are provided (Method A for OT columns, Method B for packed columns).
- Detector and gases: Uses a flame ionization detector (FID); carrier gases such as helium or nitrogen and hydrogen/dry air for the flame are recommended.
- Solvents and internal standards: Acceptable solvents include methanol, N,N‑dimethylformamide (DMF), tetrahydrofuran (THF), dipropylene glycol monomethyl ether, and toluene. Internal standard selection depends on retention times; recommended pairings (e.g., methanol with 2‑methyl‑1‑propanol, DMF with ethylbenzene) are provided.
- Calibration and quantification: Four-level calibration is required; procedures for both multi-point calibration curves and single‑point calibration are included. Results are calculated from peak-area ratios.
- Sample preparation details: Example sample masses in the standard: 4 g sample for OT-column method, 10 g sample for packed-column method, with defined volumetric dilutions and internal standard additions.
- Quality and maintenance notes: Warns of injector contamination from high‑molecular-weight polymer components; recommends monitoring and cleaning/replacing injector parts and using a liner with glass wool where helpful.
- Reporting and performance: Sections cover acceptability of results, measurement sensitivity, precision data and reporting requirements.
Applications and who uses it
- Polymer polyol manufacturers performing QC and release testing.
- Polyurethane foam and component makers verifying residual monomer levels for product safety and performance.
- Independent testing laboratories providing compliance testing for clients.
- Regulatory and safety teams assessing toxicant exposure risks (food‑contact, skin contact, furniture/cushioning).
- Use cases include routine QC, supplier verification, product development and regulatory compliance documentation.
Related standards
- ISO 472 - Plastics - Vocabulary
- ISO 648 - Laboratory glassware - Single‑volume pipettes
- ISO 1042 - Laboratory glassware - One‑mark volumetric flasks
Keywords: ISO 21257:2018, polymer polyols, residual acrylonitrile, residual styrene, gas chromatography, GC method, flame ionization detector, internal standard, polyurethane testing, polymer polyol analysis.