Overview
EN ISO 11337:2023 (ISO 11337:2023) specifies gas-chromatographic methods for determining the lactam monomers ε‑caprolactam and ω‑laurolactam in polyamides. It is aimed particularly at polyamide 6 (ε‑caprolactam) and polyamide 12 (ω‑laurolactam). The third edition (2023) updates the 2010 version and is published by CEN/ISO for harmonized European and international use.
Key topics and technical requirements
- Two validated variants of the basic GC method:
- Method A (extraction): test portion is extracted with boiling methanol; the methanol extract is injected into a gas chromatograph. An internal standard (e.g., 1‑dodecanol or isopropanol, newly allowed in 2023) is used.
- Method B (dissolution/solvent): the sample is dissolved in an appropriate solvent and the solution is injected into a gas chromatograph.
- Instrumentation: Gas chromatography with suitable detectors and either packed or capillary columns (both explicitly addressed in the 2023 revision).
- Sample preparation: grinding/milling to controlled particle size, sieving (reference to sieve sizes and ISO 565 for nominal openings), and use of extraction apparatus (Soxhlet‑type or vapour‑enveloping designs) where applicable.
- Calibration and internal standards: procedures for preparing calibration and internal‑standard solutions and for peak evaluation are specified.
- Quality aspects: method precision, solvent recovery, expression of results and required test report content are included.
- Safety and conformity: users are reminded to follow normal laboratory practice and regulatory considerations.
Applications and users
Practical applications of EN ISO 11337:2023 include:
- Quality control of polyamide resins and finished components to quantify residual monomer content.
- Incoming raw‑material testing for polyamide 6 and polyamide 12 suppliers.
- Product release testing for manufacturers in automotive, electrical, consumer goods and industrial plastics sectors.
- R&D and failure analysis where residual lactam levels affect processing, mechanical properties, odour or regulatory compliance.
Who will use it:
- Analytical laboratories, polymer QC labs, contract testing labs
- Polymer producers and compounders
- Material engineers and product development teams concerned with polyamide purity
Related standards
- ISO 472 - Plastics - Vocabulary (terms and definitions referenced)
- ISO 565 - Test sieves - Nominal sizes of openings (sieving requirements for sample prep)
- Published under the ISO/CEN Vienna Agreement; supersedes EN ISO 11337:2010.
Keywords: EN ISO 11337:2023, ISO 11337:2023, polyamides, ε‑caprolactam, ω‑laurolactam, gas chromatography, polyamide 6, polyamide 12, extraction method, Method A, Method B, 1‑dodecanol, isopropanol, Soxhlet.
