Overview - ISO 12871:2019 (olive oils, aliphatic & triterpenic alcohols)
ISO 12871:2019 specifies a laboratory method for determining the mass fraction (mg/kg) of aliphatic and triterpenic alcohols in olive oils and olive‑pomace oils using capillary gas chromatography (GC). The standard defines the analytical principle (saponification, extraction of the unsaponifiable fraction, TLC separation of alcohol fractions, derivatization to trimethylsilyl ethers) and the instrumental GC analysis required to identify and quantify target alcohols. The method is based on COI/T.20/Doc.26 Rev.2:2017 and supersedes the 2010 edition by introducing triterpenic alcohol determination.
Key topics and technical requirements
- Principle: addition of an internal standard (1‑eicosanol), saponification with ethanolic KOH, extraction of unsaponifiable matter, thin‑layer chromatography (basic silica) to isolate alcohol fractions, conversion to trimethylsilyl ethers (TMSE) and analysis by capillary GC.
- Reagents: ethanolic KOH (≈2 mol/L and 0.2 mol/L), diethyl ether, HMDS, TMCS, anhydrous pyridine, hexane/ether eluents, and TMSE reference solutions.
- Apparatus: capillary GC with flame ionization detector, fused‑silica capillary columns (20–30 m length; 0.25–0.32 mm ID; 0.10–0.30 µm film; e.g., SE‑52/SE‑54), TLC chamber and UV lamp, microsyringes, analytical balance.
- Procedure highlights: sample preparation per ISO 661, unsaponifiable extraction, TLC on basic silica gel plates (pre‑treated), GC operating and identification steps, and quantitative evaluation against internal and external standards.
- Quality parameters: the standard includes sections on precision (interlaboratory test, repeatability, reproducibility) and required elements of the test report.
Applications and who uses ISO 12871:2019
- Quality control laboratories in the olive oil industry assessing composition and compliance.
- Regulatory and food safety authorities monitoring product authenticity and labeling claims.
- Analytical contract labs offering olive oil testing (composition, adulteration screening).
- Research groups studying unsaponifiable fractions, triterpenic/aliphatic alcohol profiles, or oil processing effects.
Practical uses include verifying product quality, supporting authenticity and traceability assessments, and comparative compositional studies between olive oil types.
Related standards
- ISO 661 - Preparation of test sample (referenced for sample prep)
- ISO 5555 - Recommended sampling methods for olive oils (sampling guidance)
- COI/T.20/Doc.26 Rev.2:2017 - technical basis referenced in the standard
Keywords: ISO 12871:2019, olive oils, olive‑pomace oils, aliphatic alcohols, triterpenic alcohols, capillary gas chromatography, TMSE, thin‑layer chromatography, unsaponifiable matter.