Overview
EN ISO 19070:2016 specifies a reliable and precise chemical testing method for the determination of N-methyl-2-pyrrolidone (NMP) content in leather and leather components. Developed under the collaboration of the International Union of Leather Technologists and Chemists Societies (IULTCS) and CEN Technical Committee CEN/TC 289 “Leather,” this standard is crucial for compliance with European regulations such as REACH, which lists NMP as a substance of very high concern (SVHC). The method also covers the determination of N-ethyl-2-pyrrolidone (NEP) in leather.
This standard is applicable across the leather industry for chemical analysis purposes and ensures consistent quality control regarding solvent residues in leather products.
Key Topics
Scope and Application
- Chemical determination of N-methyl-2-pyrrolidone (NMP) in leather products and components using a standardised extraction and chromatographic quantification method.
- Also applicable for N-ethyl-2-pyrrolidone (NEP) detection.
- Supports regulatory compliance, particularly under EU REACH restrictions on NMP use.
Method Principle
- Extraction of leather samples in acetone at 50 °C using an ultrasonic bath for 1 hour.
- Subsequent chemical analysis through gas chromatography coupled with mass selective detection (GC-MS).
- Quantification through a calibration curve prepared from NMP standards.
Required Equipment and Reagents
- Analytical balance (accuracy to 0.0001 g)
- Ultrasonic bath with temperature control
- Sealable extraction containers suitable for acetone use
- Gas chromatograph with a mass selective detector (GC-MS)
- Solvents: acetone (analytical grade), and NMP standard of 99.5% purity or higher
- Micro-pipettes, volumetric flasks, PTFE membrane filters, and vials
Procedure Highlights
- Sample preparation in accordance with ISO 2418 and ISO 4044.
- Sample size of approximately 1 gram, cut into small pieces (2-3 mm).
- Extraction in acetone solvent at controlled temperature and duration.
- Filtration of the extract and immediate analysis or storage at 4 °C for up to 24 hours.
- Calibration using NMP solutions of known concentration to ensure precise quantification.
Quantification and Reporting
- Calculation of NMP content as mg per kg of leather.
- Method detection limit typically down to 5 mg/kg, suitable for monitoring low residual solvent levels.
- Test reports must include reference to ISO 19070, test date, identification details, measured NMP content, detection limit, and any deviations from the method.
Applications
- Leather manufacturers: To monitor residual chemical solvents ensuring product safety and regulatory compliance.
- Quality control laboratories: For routine testing of leather batches to control NMP and NEP content.
- Regulatory bodies: To verify adherence to chemical safety standards under EU REACH and other environmental health regulations.
- Research institutions: For studying solvent retention and emission in leather materials.
- Importers and exporters: To certify leather goods meet chemical limits demanded by international markets.
Related Standards
- ISO 2418: Leather - Sampling location for chemical, physical, mechanical and fastness tests: Provides guidelines for representative leather sampling essential for reproducibility in testing.
- ISO 4044: Leather - Preparation of chemical test samples: Details sample preparation methods which complement the procedures in ISO 19070.
- Additional relevant EN and ISO standards related to leather chemical safety and environmental regulations assist in comprehensive quality management.
This standard is an essential reference for chemical testing in the leather sector, promoting safe use of chemicals, regulatory compliance, and enhanced product quality. By adopting ISO 19070:2016, organizations ensure accurate quantification of hazardous solvents, protecting consumers and supporting sustainable leather production.