Overview - EN ISO 18218-2:2019 (Leather - Indirect method)
EN ISO 18218-2:2019 specifies an indirect analytical method for determining ethoxylated alkylphenols in leather and leather process auxiliaries. The standard covers the measurement of free alkylphenols (nonylphenol - NP, octylphenol - OP) and their ethoxylates (nonylphenol ethoxylate - NPEO, octylphenol ethoxylate - OPEO). The procedure cleaves ethoxylated alkylphenols to release the parent alkylphenol, then quantifies the released alkylphenol using HPLC (high-performance liquid chromatography) or GC‑MS (gas chromatography‑mass spectrometry).
Key topics and technical requirements
- Scope and principle: Indirect determination by chemical cleavage of ethoxylates to NP or OP, followed by chromatographic measurement.
- Instrumentation: Method supports HPLC or GC‑MS analysis for identification and quantification.
- Sample types: Applies to finished leather and leather process auxiliaries (e.g., surfactant-containing preparations).
- Sample preparation and extraction: Includes defined sampling, extraction and clean-up steps (note: solvents differ from ISO 18218-1).
- Calibration, calculation and reporting: Procedures for calibration curves, blank determinations, calculation of results and required elements in the test report.
- Annexes and examples: Normative and informative annexes provide reagent preparation (e.g., aluminium triiodide) and example chromatograms.
- Standardization context: Prepared by IULTCS in collaboration with CEN/TC 289; this edition supersedes EN ISO 18218-2:2015.
Important note: EN ISO 18218-2:2019 uses different extraction solvents than ISO 18218-1 (the direct method). Therefore, the two methods can show similar trends but may not give identical absolute values for ethoxylated alkylphenol content.
Practical applications - who uses this standard
- Leather testing laboratories performing routine or regulatory analyses for NPEO/OPEO and NP/OP.
- Leather manufacturers and chemical formulators verifying raw material and process auxiliary compliance.
- Environmental and regulatory compliance teams (REACH/EU directives) monitoring substances of concern in leather products and effluents.
- Quality assurance and product safety managers ensuring surfactant residues are within allowable limits.
- Contract testing and certification bodies issuing analytical reports for market access.
Related standards
- ISO 18218-1 - Direct method for ethoxylated alkylphenols (uses different extraction solvents and direct HPLC‑MS/MS analysis).
- ISO 2418, ISO 4044, ISO 3696 - referenced for sampling, test sample preparation and laboratory water quality.
Using EN ISO 18218-2:2019 helps organizations reliably detect and quantify ethoxylated alkylphenols in leather, supporting product safety, environmental compliance and responsible chemical management.