Overview
EN ISO 12873:2014 (identical to ISO 12873:2010) specifies a laboratory method for the determination of wax content in olive oils and olive‑pomace oils by capillary gas chromatography (GC). The method reports wax content as a mass fraction in milligrams per kilogram (mg/kg) and separates individual wax esters by carbon number (C40–C46). It is widely used to distinguish oils obtained by pressing/centrifuging from olive‑pomace oil.
Key topics and technical requirements
- Scope: Quantifies total waxes (C40–C46 esters) in olive and olive‑pomace oils; recommended for differentiating olive oil vs. pomace oil.
- Principle: Add an internal standard, fractionate the oil on a hydrated silica gel column, collect the wax fraction, and analyze by capillary GC with flame‑ionization detection (FID).
- Reagents & standards: hydrated silica gel (2% water), n‑hexane, diethyl ether, n‑heptane, Sudan I dye, and an internal standard (e.g., lauryl arachidate).
- Apparatus: liquid chromatography column (glass), fused‑silica capillary GC column (SE‑52/SE‑54 or equivalent), cold on‑column injector, programmable oven, FID, and computer integration.
- Chromatographic conditions (recommended): temperature program to separate C40–C46 esters, detector at high temperature (example: 350 °C), carrier gas helium or hydrogen, injection volume ~1 µL on-column.
- Sample preparation: silica gel packing, cleanup with n‑hexane, elution with a fresh n‑hexane/diethyl ether (99/1 v/v) mixture, visual check with Sudan I dye, solvent removal, reconstitution in n‑heptane for GC.
- Quantification: calculate wax content from peak areas of the individual esters (C40–C46) relative to the internal standard, and report the sum in mg/kg (one decimal).
- Precision & reporting: Annex B summarizes interlaboratory precision (repeatability and reproducibility limits). Test reports must identify sample, method reference, results and any deviations.
Applications and users
- Who uses it: food testing laboratories, olive oil producers, regulatory authorities, quality control departments, and research labs in the edible‑oil sector.
- Practical uses:
- Authentication and classification of olive oils and olive‑pomace oils.
- Regulatory compliance and trade quality control.
- Routine QC testing during production and after storage to monitor wax levels.
Related standards
- ISO 661 - preparation of test sample for fats and oils.
- ISO 5555 - recommended sampling for olive oils (sampling not part of EN ISO 12873).
Keywords: EN ISO 12873:2014, olive oil wax content, olive‑pomace oil, capillary gas chromatography, wax determination, gas chromatograph, C40–C46 wax esters, olive oil analysis.