ISO 20418-1:2018

Overview

ISO 20418-1:2018 specifies a qualitative and quantitative proteomic method for identifying and measuring the content of animal hair fibres-wool, cashmere and yak-in textiles. The procedure combines light microscopy for preliminary fiber identification with protein chemistry and mass spectrometry: proteins are extracted (thiourea/urea/DTT), enzymatically digested (trypsin) and peptide markers are detected by liquid chromatography–electrospray ionization–mass spectrometry (LC‑ESI‑MS). The method is designed for samples with a homogeneous distribution of components and can be applied at any processing stage (raw material to garment).

Key topics and technical requirements

• Scope: Analysis of staples, tops, yarns and fabrics containing wool, cashmere or yak and their blends (not applicable to blends of fibres from the same species, e.g., cashmere + mohair).
• Preliminary screening: Morphological fiber identification by light microscopy in accordance with ISO 17751‑1.
• Protein extraction: Use of a tris/thiourea/urea/DTT buffer, long contact extraction (examples: two days at 50 °C), filtration and centrifugation.
• Enzymatic digestion: Trypsin digestion of extracted proteins with reduction/alkylation steps (DTT, iodoacetamide) to generate marker peptides.
• LC‑ESI‑MS analysis: Tryptic peptides analyzed by LC‑ESI‑MS; quantitative data often acquired by Single Ion Recording (SIR) to integrate chromatographic areas for marker peptides.
• Calculation & reporting: Percent composition derived from marker peak areas; report must reference ISO 20418‑1 and include sample ID, equipment, and results with confidence limits. A corrective factor may be required (e.g., yak overestimation depending on equipment).
• Quality practices: Use analytically graded reagents and standard lab apparatus (Soxhlet, microtome, centrifuge, LC‑MS). Annexes provide example parameters, marker lists and interlaboratory data.

Applications and users

Who uses ISO 20418‑1:2018:

• Textile testing laboratories performing authentication and composition analysis
• Quality control teams at fibre processors, knitwear manufacturers and retailers
• Regulatory and consumer-protection bodies investigating fibre-labelling claims or fraud (e.g., cashmere content)
• R&D groups developing proteomic assays for speciality fibres

Practical applications:

• Verifying declared wool, cashmere or yak percentages in blends
• Supporting anti‑fraud and traceability efforts in high-value textile supply chains
• Complementing microscopy and chemical methods (ISO 17751, ISO 1833) for comprehensive composition analysis

Related standards

• ISO 17751 (all parts) - microscopy and quantitative analysis of specialty animal fibres
• ISO 1833 (all parts) - quantitative chemical analysis of textile mixtures
• ISO 137:2015 - wool fibre diameter measurement (projection microscope method)

Keywords: ISO 20418-1:2018, textiles, proteomic analysis, LC-ESI-MS, peptide detection, wool, cashmere, yak, trypsin digestion, marker peptides, fibre composition.