Overview
EN ISO 13365-1:2020 (Corrected 2021-03) specifies a standardized laboratory method for the chemical determination of preservative agents in leather using acetonitrile solvent extraction followed by liquid chromatography (HPLC) with UV or mass spectrometric (MS) detection. The method targets the total solvent‑extractible content of four common leather preservatives: TCMTB, PCMC, OPP, and OIT, and can also detect their breakdown products. This standard is published by CEN/ISO and supersedes EN ISO 13365:2011.
Key topics and technical requirements
- Scope: Determination of 2-(thiocyanomethylthio)-benzothiazole (TCMTB), 4-chloro-3-methylphenol (PCMC), 2-phenylphenol (OPP) and 2-octylisothiazol-3(2H)-one (OIT) in leather.
- Sample preparation: Sampling per ISO 2418; sample preparation per ISO 4044. Wet intermediates must be dried before testing.
- Extraction: ~1 g leather extracted with 20 ml acetonitrile in an ultrasonic bath (≈40 kHz) for 1 h ± 5 min at room temperature (mixture may reach ~35 °C).
- Filtration/clarification: Optional membrane filtration (polyamide, 0.45 µm) or centrifugation of extracts.
- Chromatography: HPLC with UV or MS detection using reversed‑phase C8 or C18 columns (pre‑column recommended). Annex A provides recommended chromatographic conditions and MS options.
- Reagents & purity: HPLC-grade acetonitrile; deionized water (ISO 3696 grade 3); analytical/LC‑MS grade solvents and standards. Target compound standards specified (≥97–99.7% purity).
- Calibration: At least four calibration solutions prepared in acetonitrile (range examples: 2 to 100 mg/L) to produce linear calibration of peak area vs concentration. Store calibration solutions at (4 ± 3) °C.
- Reporting: Calculate total solvent‑extractible content and record sampling, extraction and chromatographic parameters.
Applications and users
- Quality control and routine testing in tanneries and leather finishing operations
- Independent analytical laboratories performing regulatory or supplier compliance testing
- Product safety and environmental teams assessing preservative residues and potential breakdown products
- Research groups studying preservative behavior, microbiological protection, or leather chemistry
Related standards
- ISO 13365 series (Part 2 complements extraction with alternative methods)
- ISO 2418 - sampling location for leather
- ISO 4044 - preparation of chemical test samples
- ISO 3696 - laboratory water quality
- ISO 4684 - determination of volatile matter
Keywords: EN ISO 13365-1:2020, leather preservative analysis, acetonitrile extraction, HPLC, LC-MS, TCMTB, PCMC, OPP, OIT, leather testing, chemical determination.