Overview
CEN ISO/TS 22115:2021 - "Animal and vegetable fats and oils - Separation of lipid classes by capillary gas chromatography (fingerprint method)" - defines a semi-quantitative capillary GC fingerprinting method for oils, fats and oil/fat-related samples (including deodistillates). The technique provides a single-analysis overview of main lipid classes (e.g. triglycerides) and minor components (e.g. sterols, sterol esters, tocopherols, wax esters, fatty alcohols, glycerol). It is intended for screening and relative comparison of sample compositions rather than fully quantitative determination of pre‑identified compound classes.
Key topics and technical requirements
- Analytical principle: Hydroxylated compounds are converted to silyl derivatives and analyzed by capillary gas chromatography (GC) on a high‑temperature column; non‑hydroxylated (apolar) compounds remain unaffected.
- Instrumentation: Requires a GC for capillary columns with an on‑column injector (or equivalent), temperature‑programmable oven and flame ionization detector (FID); a fused silica capillary column rated up to ~400 °C with low film thickness is recommended.
- Reagents and standards:
- Silylation reagent (example mixture: MSHFBA + methylimidazole, 1 ml + 50 µL).
- Internal standard: 1,2,3‑tridecanoylglycerol.
- Reference compounds used for response factor determination include oleic acid, mono/di/triglycerides, tocopherols, cholesterol, cholesterol esters, squalene, plant sterol mix, etc.
- Solvents: isooctane, chloroform (chromatographic grade).
- Sample preparation: Follow ISO 661 for test‑sample preparation; perform silylation of sample and standards prior to GC.
- Data treatment: Peak identification and integration, calculation of response factors from reference standards, and semi‑quantitative reporting. The method includes criteria for repeatability, reproducibility and interlaboratory precision (informative annexes with example chromatograms and interlab results).
- Limitations: Designed as a fingerprint/screening method-use dedicated, validated quantitative methods when absolute quantification of a given class is required.
Applications and users
- Food and oil testing laboratories performing quality control, compositional screening and batch comparison.
- Producers of edible oils and fats and processors of fat‑derived ingredients who need rapid profiling of major and minor lipid classes.
- Regulatory or research labs conducting authenticity screening, compositional surveys or comparative studies of deodistillates and refined streams.
- Useful for preliminary screening prior to targeted quantitative analyses.
Related standards
- ISO 661 - Animal and vegetable fats and oils - Preparation of test sample (normative reference cited in CEN ISO/TS 22115:2021).
- CEN/TC 307 and ISO/TC 34 collaboration context - this document is a CEN‑endorsed ISO Technical Specification, initially provisional for three years.
Keywords: CEN ISO/TS 22115:2021, capillary gas chromatography, lipid classes, fingerprint method, oils and fats screening, silylation, GC‑FID, semi‑quantitative analysis.