Overview
ISO 10638:2017 - Rubber - Identification of antidegradants by gas chromatography/mass spectrometry (GC‑MS) - specifies a qualitative analytical method for identifying antidegradants in raw rubbers, latices, unvulcanized-rubber compounds and vulcanized-rubber products. It covers identification of the 31 antidegradant types listed in Annex A and provides supporting chromatograms/mass spectra (Annex B) and a procedure for determining gas‑chromatographic retention index (Annex C). The method is intended for identification only and is not for quantitative analysis.
Key technical topics and requirements
- Analytical principle: Antidegradants are recovered by either thermal desorption or solvent extraction and separated/identified using gas chromatography/mass spectrometry (GC‑MS). Retention indices can supplement mass‑spectral identification.
- Thermal‑desorption method: Uses a desorption device (or low‑temperature pyrolyzer) connectable to the GC; desorption temperatures up to 350 °C are specified. Typical GC conditions include carrier gas (helium) flow 1.0–2.0 ml/min and injector temperature 300–350 °C.
- Solvent‑extraction method: Uses acetone in a Soxhlet extractor (approx. 8 h extraction for ~2 g sample), concentration to 10–20 ml and injection of 1 µl for GC‑MS analysis. If sample dissolves in acetone, thermal desorption is preferred.
- GC column and MS parameters: Recommended column dimensions (25–60 m length, 0.25–0.35 mm i.d., 5 % diphenyl/95 % polydimethylsiloxane phase) and MS settings (electron ionization at 70 eV; scan m/z 50–600; interface ~300 °C) are specified to ensure reproducible identification.
- Data analysis: Compare mass spectra to Annex B figures and Table A.1, and verify retention indices (Annex C) when available. The method recognizes that multiple antidegradants or decomposition products can be present.
Practical applications
- Quality control and incoming material inspection for rubber manufacturers and compounders.
- Failure analysis and forensic investigation of rubber products to determine antidegradant presence.
- Environmental and regulatory screening where identification of specific antidegradants is required.
- R&D and formulation development to confirm antioxidant/antidegradant types in raw and finished rubber articles.
Who should use ISO 10638:2017
- Analytical laboratories with experienced GC‑MS operators.
- Industrial QC teams in tire, hose, seal, and other rubber product sectors.
- Environmental testing and compliance laboratories, and product stewardship groups assessing formulation impacts.
Related standards
- ISO 123 (Rubber latex - Sampling)
- ISO 124 (Latex - Determination of total solids)
- ISO 1407 (Rubber - Determination of solvent extract)
- ISO 1795 (Rubber - Sampling and preparative procedures)
- ISO 4645 (Thin‑layer chromatography methods for antidegradants - alternative qualitative approach)
Keywords: ISO 10638:2017, GC‑MS, antidegradants, rubber testing, thermal desorption, solvent extraction, retention index, Soxhlet extraction.
