Overview
ISO 24363:2023 specifies a validated gas chromatography (GC) method for the determination of fatty acid methyl esters (FAME) - including saturated, cis- and trans‑mono‑ and polyunsaturated FAME from C12 to C24 - and squalene in olive oil and other vegetable oils. The standard describes sample preparation, reagent requirements, GC operating conditions and quantitative expression of results (area %, mass g/100 g and squalene in mg/kg), enabling reproducible laboratory analysis for quality control, labeling and research.
Key technical topics and requirements
- Scope: FAME C12–C24 (saturated, cis/trans mono- and polyunsaturated) and squalene by capillary GC.
- Sample prep:
- Trans‑esterification with methanolic KOH (2 M) at room temperature to form FAME.
- For oils with free fatty acids (FFA) > 2.0%, a silica-gel SPE clean-up is recommended to remove FFA before methylation.
- Drying of extract (anhydrous Na2SO4) and short-term refrigerated storage (≤ 12 h) prior to analysis.
- Standards and calibration:
- Use of internal standard (C21:0 FAME, 5.0 mg/mL in heptane) for quantification by mass.
- Squalene quantified via an external calibration curve (stock 10.0 mg/mL; standards 0.5–5.0 mg/mL).
- Reference mixtures for isomer identification and system suitability (critical pairs: C18:3/C20:1 and C23:0/squalene).
- GC instrumentation and conditions:
- Capillary column (e.g., SP‑2560 or CP Sil 88, 100 m × 0.25 mm, 0.25 µm film).
- Injector/detector temperatures: 250 °C; FID detection.
- Oven program: start 165 °C (30 min), ramp 2 °C/min to 200 °C, hold 12 min.
- Carrier gas (hydrogen or helium), split injection (1:100), injection volume 1 µL.
- Data & performance:
- Results expressed as % area of total FAME, g/100 g (with internal standard), and squalene in mg/kg.
- System suitability checks and documented interlaboratory precision/repeatability criteria are included.
Practical applications and users
ISO 24363:2023 is intended for:
- Food testing laboratories performing olive oil authenticity and composition analysis.
- Quality control teams in olive oil and vegetable oil production.
- Regulatory bodies monitoring trans fatty acids and label claims.
- Research labs studying oil composition, oxidation or varietal differences.
Benefits include standardized, reproducible quantification of FAME profiles and squalene - important for nutritional labeling, fraud detection and product specification.
Related standards
- ISO 661 - Preparation of test sample (referenced for sample prep).
- ISO 5555 - Recommended sampling methods (sampling recommended but not part of the method).
Keywords: ISO 24363:2023, FAME analysis, squalene determination, gas chromatography, olive oil, GC‑FID, cis trans fatty acids, vegetable oil testing.