Overview
ISO 18219-2:2021 - Leather - Determination of chlorinated hydrocarbons in leather - Part 2: Chromatographic method for middle-chain chlorinated paraffins (MCCPs) specifies a laboratory procedure to quantify MCCPs (C14–C17) in processed and unprocessed leather. The method defines sample extraction, clean-up, instrumental analysis (primary GC‑ECNI‑MS; optional LC‑MS/MS in Annex B), calibration and result reporting for reliable measurement of MCCPs in leather products.
Key topics and technical requirements
- Scope: Determination of MCCPs C14–C17 in leather using chromatographic methods.
- Sampling and sample prep: Follow ISO 2418 for sampling location and ISO 4044 for sample preparation; remove glue residues before testing.
- Extraction: Ultrasonic extraction with n‑hexane (9.9 mL per 0.5 g leather) at (60 ± 5) °C for (60 ± 2) min. Internal standard (lindane) added prior to extraction.
- Clean-up: Sulfuric acid clean‑up (1 mL H2SO4 added to 5 mL hexane extract, shaken 10 min) and phase separation; 1 mL hexane phase taken for analysis.
- Calibration: Use a 55% chlorination MCCP calibration standard prepared by mixing 52% and 57% technical standards and spiking with the internal standard. Calibration checks are required after every ten samples.
- Instrumental analysis: Primary method is GC‑ECNI‑MS (gas chromatography with electron capture negative ion chemical ionization mass spectrometry). Annex A gives example GC‑ECNI‑MS parameters; Annex B provides LC‑MS/MS options where equivalent accuracy is demonstrated.
- Quantification and evaluation: Sum peak areas of four quantifier ions (including m/z 403 and 417) using peak shape evaluation (PSE). Ions m/z 431 and 445 are only counted if their area is >10% of m/z 403/417 and pass PSE checks.
- Interferences & limits: SCCPs and sulfochlorinated paraffins can interfere; if SCCPs exceed ~1% the result should be reported as “n.d.” with an explanatory comment. Method LOQ/feasible quantification reported around 100 mg/kg.
- Reporting: Test report must reference ISO 18219-2:2021 and include method details and results.
Applications and users
- Who uses it: Accredited testing laboratories, leather manufacturers, quality control units, regulatory agencies, and product safety auditors.
- Practical uses: Compliance testing for chemical regulations and restricted-substance lists, raw material screening, supplier control, environmental and safety assessments of leather goods (footwear, garments, upholstery).
Related standards
- ISO 2418 - Leather sampling location
- ISO 4044 - Preparation of chemical test samples
- Other parts of the ISO 18219 series (see ISO website for the full list)
Keywords: ISO 18219-2:2021, MCCPs, middle-chain chlorinated paraffins, leather testing, GC‑ECNI‑MS, LC‑MS/MS, extraction, sulfuric acid clean‑up, calibration standard.