Overview
EN ISO 4044:2017 - Leather - Chemical tests - Preparation of chemical test samples specifies standardized procedures for preparing leather specimens for chemical analysis. Published by CEN/ISO and prepared with IULTCS input, the standard defines two accepted preparation routes - grinding to produce “ground leather” or cutting into small pieces - and gives practical requirements for apparatus, sample conditioning, storage, and reporting.
Key topics and technical requirements
- Preparation methods
- Grinding (6.2): Use when a sufficiently large piece is available (guideline: ≥ 200 mm × 200 mm or > 10 g). Reduce pieces before milling and ensure representative grinding.
- Cutting (6.3): Use when only small pieces are available (e.g., parts of consumer items). Cut pieces to 3 mm–5 mm side length with a sharp blade.
- Apparatus (5):
- Grinding mill: blade rotational frequency 300–1 000 r/min; preferred lower speeds to avoid heating; sieving plate perforations (4.0 ± 0.5) mm; blades must be sharp.
- Cutting tool: suitable sharp-blade device for producing 3–5 mm pieces.
- Design/material considerations to avoid contamination: use chromium‑free steel parts and hardened tungsten‑carbide blades where required.
- Temperature and moisture control
- Do not allow sample temperature to exceed 40 °C during drying or grinding.
- Wet samples (> ~30% moisture) should be pre-dried at ≤ 40 °C; if dried, condition per ISO 2419 before testing.
- Cleaning and contamination
- Ensure mills and collection devices are clean; do not use water for cleaning. If sufficient sample is available, run and discard a few initial small pieces to purge the mill before collecting the test sample.
- Storage and reporting
- Mix test material thoroughly after preparation and store in a clean, dry, airtight container away from heat sources.
- Report the chosen preparation method in the test report (6.4).
Practical applications and users
- Routine laboratory chemical analysis of leather (extractables, residues, heavy metals, tanning agents).
- Quality control in tanneries, leather product manufacturers, testing laboratories, and compliance labs.
- Useful for analysts preparing samples from full hides, panels or small product pieces (footwear, garments, upholstery).
- Helps ensure reproducible, representative samples for downstream analytical methods (chromatography, spectroscopy, atomic absorption, etc.).
Related standards
- ISO 2419 - Leather: sample preparation and conditioning (referenced for conditioning after drying).
- EN 15987 - Leather terminology (terms and definitions).
- EN ISO 4044:2017 supersedes EN ISO 4044:2008; Annex A provides informative commercial apparatus guidance.
Keywords: EN ISO 4044:2017, Leather chemical tests, preparation of chemical test samples, ground leather, cutting leather samples, grinding mill, sample preparation for leather.
