Overview
ISO 20686:2025 specifies a validated laboratory method to quantify residues of certain organic solvents in footwear and footwear components using gas chromatography–mass spectrometry (GC‑MS). The standard targets solvent residues that can remain from adhesives, leather finishing, coated textiles, plastics and rubber. It defines sample preparation, extraction, analytical conditions, calibration and calculation procedures to produce traceable, comparable results for risk assessment and regulatory compliance.
Key topics and technical requirements
- Scope and purpose: Quantitative determination of selected organic solvents (see Annex A) that are potentially harmful to consumers and regulated in some jurisdictions (e.g., EU Regulation No 1907/2006 - REACH).
- Sample preparation: Single-material specimens (leather, textile, polymer etc.) cut to 3–5 mm pieces and prepared per ISO 21061.
- Extraction method: Methanol extraction with an internal standard; 1 g sample extracted in 20 ml methanol using a thermostatic ultrasonic bath at (40 ± 5) °C for (60 ± 5) min, followed by filtration.
- Analytical technique: GC‑MS (mass selective detector) for identification and quantification. Annex B provides example GC‑MS parameters; Annex C defines MS characteristics; Annex D shows a sample total ion chromatogram.
- Standards and calibration: Use of stock solutions and at least five calibration levels with internal standardization. Example calibration levels and concentration ranges are included.
- Reagents and apparatus: Analytical‑grade methanol, acetone, internal standards (e.g., EGMEA, EGBE, NMF), PTFE membrane filters, amber GC vials, analytical balance and GC‑MS instrumentation. Glassware cleaning and nitric acid rinse procedures are specified to avoid contamination.
- Result expression: Linear regression using peak‑area ratios and a defined formula for converting GC‑MS response to residual solvent content (mg/kg). Method performance and limits of quantification are addressed.
Applications and typical users
ISO 20686:2025 is intended for:
- Footwear manufacturers and material suppliers performing incoming material checks and final product testing.
- Third‑party testing laboratories providing compliance testing for brands and retailers.
- Regulatory bodies and conformity assessment organizations monitoring solvent residues and consumer safety.
- Quality assurance and product safety teams implementing chemical risk management and supplier control.
Practical uses include routine quality control, pre‑shipment testing, regulatory compliance (chemicals legislation), and forensic/root‑cause investigations of solvent contamination.
Related standards
- ISO 21061 - Footwear: sample preparation principles for chemical tests.
- ISO 4787 - Volumetric instruments: capacity testing and use.
- ISO/TR 16178 (referenced in the introduction) - guidance on materials of concern and solvent occurrence.
Keywords: ISO 20686, footwear testing, organic solvents, solvent residues, GC‑MS, methanol extraction, calibration, consumer safety, REACH compliance.