Overview
EN ISO 25712:2026 outlines an internationally recognized method for determining the total (solvent extractable) content of melamine in chemical substances used in the leather tanning industry. Developed jointly by CEN and ISO, this standard stipulates a robust analytical procedure utilizing liquid chromatography (LC), with detection performed using triple quadrupole mass spectrometry (MS/MS), an ultraviolet (UV) detector, or a diode array detector (DAD).
Melamine, a key component in melamine-formaldehyde resins used during retanning, is considered a Substance of Very High Concern (SVHC) in the European Union, drawing increased regulatory attention. Accurate, harmonized quantification of melamine in leather-processing chemicals is essential for safety, regulatory compliance, and quality assurance throughout the supply chain.
Key Topics
- Purpose: Establishes a standardized method for analyzing and quantifying total melamine in chemicals used for leather tanning.
- Scope: Applicable to all chemicals for the leather tanning industry containing or suspected of containing melamine, notably resins and compound products.
- Instrumentation:
- LC-MS/MS: Delivers high sensitivity and low limits of quantification (LoQ), suitable for strict regulatory needs.
- LC-UV and LC-DAD: Provides broader accessibility for laboratories, with higher (but still adequate) LoQ.
- Sample Preparation: Involves extraction in an acetonitrile:water mixture, with specific sample homogenization and preparation steps to ensure representative and reproducible results.
- Chromatographic Options:
- Hydrophilic Interaction Liquid Chromatography (HILIC): Preferred for highly polar melamine, offering optimal separation.
- Reversed Phase (RP) Chromatography (C8 or C18 columns): Provided as a practical alternative for widespread laboratory compatibility.
- Calculation Methods: Offers formulas for result calculation, both with and without the use of internal standards, to accommodate different laboratory protocols and instrumentation.
- Reporting: Specifies minimum requirements for the test report, including methodology, sample information, detection type, and quantitative result.
Applications
- Regulatory Compliance: Supports adherence to EU and international regulations regarding SVHC substances and reinforces documentation for REACH and other chemical safety frameworks.
- Quality Control in Leather Production: Enables manufacturers and suppliers of tanning chemicals to verify and document melamine levels, reducing risk to end-users and consumers.
- Supply Chain Integrity: Provides a harmonized standard that can be implemented globally, ensuring consistent quality and safety standards across markets.
- Laboratory Accreditation: Facilitates method adoption in both highly equipped (MS/MS) and broadly accessible (UV/DAD) laboratories by offering validated alternatives.
- Research and Development: Assists R&D teams in assessing raw materials or finished chemical formulations during product innovation or improvement projects.
Related Standards
- EN ISO 17025 - Requirements for testing and calibration laboratories.
- EN ISO 2418 - Leather - Chemical, physical and mechanical and fastness tests - Sampling location.
- ISO 4047 - Leather - Determination of Chromium(VI) content.
- REACH Regulation (EC) No. 1907/2006 - Registration, Evaluation, Authorization and Restriction of Chemicals in the EU, referencing SVHC such as melamine.
- IULTCS Methods - International standards for sampling and testing in the leather industry.
- EN ISO 2419 - Leather - Physical and mechanical tests - Sample preparation and conditioning.
By complying with EN ISO 25712:2026, Chemicals for the leather tanning industry - Determination of the total content of melamine, stakeholders across the leather value chain can ensure accurate melamine analysis, uphold regulatory requirements, and maintain the integrity of their products in international markets.
