Overview
ISO 17234-1:2024 - Leather - Chemical tests for the determination of certain azo colourants in dyed leathers - Part 1: Determination of certain aromatic amines derived from azo colourants specifies a laboratory method to detect and quantify aromatic amines released from azo colourants in dyed leather. The method targets substances listed in regulatory lists (e.g., REACH Annex XVII Appendix 8 and GB 20400-2006) that are potential health hazards (many are carcinogenic).
Key topics and technical requirements
- Scope: Determination of specific aromatic amines produced by reductive cleavage of azo groups in leather colourants.
- Sample preparation: Degreasing and controlled reductive cleavage using sodium dithionite in citrate buffer (pH 6) at 70 °C in a closed reaction vessel.
- Extraction: Transfer of liberated amines into t‑butyl methyl ether via liquid–liquid extraction using diatomaceous earth columns; an alternative screening extraction without diatomaceous earth is given in Annex D.
- Concentration and cleanup: Concentration under mild conditions (rotary vacuum evaporator) and re-dissolution in solvent suitable for chromatographic analysis.
- Analytical methods: Identification by at least two different chromatographic separation techniques (to avoid misinterpretation from interfering isomers) - options include LC‑DAD, LC‑MS, GC‑MS, CE‑DAD, and qualitative (H)TLC. Quantification is performed by LC‑DAD, LC‑MS or GC‑MS.
- Controls and calibration: Use of certified amine standards and process controls; calibration procedures and calculation of results are specified.
- Safety: Strong warnings - target aromatic amines are known or suspected carcinogens. Good laboratory practice, PPE, and compliance with local safety regulations are required.
- Documentation: Test report content and reliability assessment (Annex B) plus chromatographic guidance (Annex A).
Practical applications and users
ISO 17234-1:2024 is used by:
- Leather testing and analytical laboratories performing compliance testing for REACH and national regulations.
- Tanneries and leather manufacturers conducting raw material and finished-product safety assessments.
- Product safety and regulatory compliance teams verifying that dyed leathers do not release restricted aromatic amines.
- Certification bodies and auditors assessing chemical safety and labelling requirements.
Practical benefits include standardized, reproducible workflows for detecting carcinogenic aromatic amines, enabling consistent compliance decisions and helping manufacturers reduce chemical risk in consumer leather goods.
Related standards
- ISO 17234-2 (determination of 4‑aminoazobenzene)
- ISO 2418, ISO 3696, ISO 4044 (sampling, water quality and test sample preparation)
- Normative Annexes E and F (methods for colourant analysis and free aromatic amines)
Keywords: ISO 17234-1:2024, aromatic amines, azo colourants, leather testing, LC‑MS, GC‑MS, chemical tests, REACH compliance.