Overview
EN ISO 18219-2:2021 - Leather - Determination of chlorinated hydrocarbons in leather - Part 2: Chromatographic method for middle‑chain chlorinated paraffins (MCCPs) - is a CEN/ISO test method that specifies a chromatographic procedure to quantify middle‑chain chlorinated paraffins (MCCPs, C14–C17) in processed and unprocessed leathers. The standard addresses sample preparation, extraction, clean‑up and instrumental analysis using GC‑ECNI‑MS (gas chromatography with electron capture negative ion chemical ionization mass spectrometry), with an LC‑MS(/MS) alternative in Annex B for improved resolution of interferences.
Key topics & technical requirements
- Scope and target analytes: MCCPs with carbon chain lengths C14–C17; typical chlorine content range 40–70% (calibration often uses a 55% chlorination reference).
- Sample preparation:
- Extraction with n‑hexane in a sealable 20 ml vessel.
- Ultrasonic bath extraction at about 60 °C for 60 minutes.
- Sulfuric acid clean‑up to remove matrix interferences prior to analysis.
- Calibration and standards:
- Preparation of MCCP calibration solutions (e.g., 50 µg/ml, 55% chlorination) and use of an internal standard (lindane specified in the method).
- Comparison of sample chromatograms with the defined calibration standard mixture.
- Analytical detection:
- Primary method: GC‑ECNI‑MS, using multiple ion traces (four ion traces recommended) for identification and quantification of MCCPs.
- Alternative: LC‑MS/MS (Annex B) when proven to provide equivalent accuracy or to resolve GC interferences (e.g., sulfochlorinated paraffins, chloroalkenes).
- Quality aspects:
- Requirements for apparatus (analytical balance, ultrasonic bath, GC‑ECNI‑MS).
- Sections on expression of results, evaluation, interferences and precision; test report content is specified.
Practical applications & who uses it
- Leather manufacturers and finishers - routine monitoring of MCCP content in raw and finished leather to control chemical inputs and ensure product safety.
- Analytical laboratories and testing services - standardized method for reliable quantification and inter‑laboratory comparability.
- Regulatory and compliance bodies - supports enforcement and surveillance programs where chlorinated hydrocarbons in leather are restricted or monitored.
- Product safety, environmental and procurement teams - assessing persistence/bioaccumulation risks linked to chlorinated paraffins in leather goods.
Related standards
Keywords: EN ISO 18219-2:2021, MCCPs, middle-chain chlorinated paraffins, leather testing, GC‑ECNI‑MS, LC‑MS/MS, chlorinated hydrocarbons, chromatographic method, C14–C17.
