Quick, Accurate Testing of FAMEs in Olive Oil by GC/FID Using a Zebron™ ZB-FAME GC Column

Importance of the topic

Olive oil is one of the most widely adulterated food products globally. Monitoring its fatty acid profile is essential both to confirm product authenticity and to assess nutritional and sensory quality. Conventional gas chromatography methods for fatty acid methyl esters (FAMEs) often require long columns and extended analysis times, limiting laboratory throughput and delaying quality control decisions.

Objectives and study overview

This study aimed to evaluate a shorter, high-selectivity GC column (Zebron ZB-FAME) for rapid, accurate quantitation of nine key FAME isomers in regular and extra virgin olive oils. The work follows the International Olive Council (IOC) method COI/T.20/Doc. No 25 and compares separation efficiency and run times against traditional longer columns.

Methodology

Samples of regular and extra virgin olive oil were obtained from a local retailer. Each oil was subjected to solid-phase extraction (Strata® Si-1 cartridges) to remove matrix interferences, followed by derivatization to FAMEs using potassium hydroxide in methanol. The resulting heptane layer was directly injected into the GC system after a 5:1 dilution in heptane.

Applied instrumentation

Gas chromatograph with flame ionization detector (GC/FID)

• Column: Zebron ZB-FAME, 30 m × 0.25 mm × 0.20 μm
• Carrier gas: Helium at 1.2 mL/min (constant flow)
• Oven program: 100 °C (2 min) to 140 °C at 10 °C/min, then 190 °C at 3 °C/min, finally to 260 °C at 30 °C/min (2 min hold)
• Injection: Split 50:1, 1 µL at 240 °C
• Detector: FID at 260 °C
• SPE Cartridge: Strata Si-1, 1 g/6 mL

Main results and discussion

All nine FAME isomers, including the internal standard C11:0, were fully resolved in under 20 minutes. The high-cyanopropyl phase delivered effective cis/trans discrimination, and the 30 m column length provided sufficient resolution of major FAMEs such as palmitic (C16:0), oleic (C18:1), and linoleic (C18:2) methyl esters. No significant coelutions or matrix interferences were observed, and the large oleic acid peak remained well separated from neighboring analytes.

Benefits and practical applications

By reducing run times from over 60 minutes to approximately 20 minutes, laboratories can significantly increase sample throughput for routine olive oil authenticity and quality testing. The method maintains accuracy and resolution while lowering operational costs and improving turnaround times for QA/QC workflows.

Future trends and potential applications

Further optimization could include faster temperature ramps or bake-out steps to extend column lifetime and throughput. Emerging column chemistries and shorter dimensions promise even quicker analyses. Integration with automated derivatization, multidimensional GC, or mass spectrometric detection may enhance sensitivity and broaden application to other edible oils and lipid matrices.

Conclusion

The Zebron ZB-FAME GC column delivers rapid, reliable separation of key olive oil FAMEs in under 20 minutes, aligning with IOC guidelines and enabling substantial productivity gains for food testing laboratories.

References

International Olive Council, Official Method COI/T.20/Doc. No 25