Overview
ISO 16179:2025 - Footwear - Determination of organotin compounds in footwear materials - specifies a laboratory test method to qualify and quantify organotin compounds in footwear materials (excluding metal hardware). The method uses gas chromatography coupled with mass spectrometry (GC‑MS or GC‑MS/MS) after extraction and chemical derivatization. The 2025 edition upgrades the 2012 technical specification to a full ISO standard and adds GC‑MS/MS capability, updated extraction solvent guidance and revised sample preparation references.
Key topics and technical requirements
- Scope: Applicable to all footwear materials except metal hardware (see ISO/TR 16178). Method can be extended to additional organotins after validation.
- Principle:
- Extraction of organotins from material with methanol in mildly acidic conditions using tropolone as a complexing agent.
- Conversion to volatile alkyl derivatives by reaction with sodium tetraethylborate (NaB(Et)4).
- Separation and detection by GC‑MS or GC‑MS/MS.
- Target compounds: Mono-, di-, tri‑ and tetra‑substituted organotins (examples include trimethyltin, di‑n‑butyltin, tri‑n‑butyltin, triphenyltin); internal standards are specified (e.g., n‑heptyltin trichloride).
- Reagents & apparatus: Methanol, tetrahydrofuran (THF), tropolone, sodium tetraethylborate, n‑hexane, inert gas, analytical balance, ultrasonic bath, centrifuge, GC‑MS/MS system and GC vials.
- Sample preparation: Prepare test specimens per ISO 21061; particle size ≤ 4 mm edge length; up to three specimens of same material may be combined.
- Safety: Sodium tetraethylborate is air‑sensitive and potentially pyrophoric; prepare in a fume hood or inert atmosphere. Organotins are toxic and endocrine disruptors - handle with appropriate PPE and controls.
- Documentation: Method includes calibration, internal standards, blank controls, expression of results and precision metrics; annexes provide recommended GC conditions, MS parameters and method reliability.
Applications
- Regulatory compliance testing (e.g., EU restrictions referenced in the standard).
- Brand restricted substances list (RSL) verification and supplier audits.
- Quality control for footwear manufacturers and material suppliers.
- Third‑party conformity testing labs offering chemical safety testing of footwear components.
Who should use this standard
- Analytical laboratories performing chemical testing on footwear.
- Footwear manufacturers and suppliers responsible for material safety and compliance.
- Compliance officers, product safety teams, and procurement specialists managing RSL and REACH obligations.
- Standards bodies and certification organizations validating test methods.
Related standards
- ISO 21061 - Sample preparation for footwear chemical tests
- ISO 3696 - Water for analytical laboratory use
- ISO 4787 - Volumetric instruments (glassware)
- ISO/TR 16178 - Guidance on metal hardware (exclusion for this method)
Keywords: ISO 16179:2025, organotin, footwear testing, GC‑MS, GC‑MS/MS, sodium tetraethylborate, tropolone, restricted substances, RSL, sample preparation.
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