Analysis of FAME in soya bean oil

Importance of the Topic

Soya bean oil is a key edible oil rich in fatty acids that influence nutritional value, stability, and functional properties of food products. Accurate profiling of fatty acid methyl esters (FAME) is essential for quality control, authenticity testing, and compliance with regulatory standards in the food and agricultural sectors. Chromatographic separation of FAME provides critical data for lipid composition analysis, enabling laboratories to monitor product consistency and detect adulteration.

Objectives and Study Overview

This application note demonstrates a robust gas chromatography–flame ionization detection (GC–FID) method for resolving FAME components in soya bean oil. The goals are to achieve high resolution of isomeric species, maintain column stability over repeated runs, and deliver reliable quantification of both major and trace fatty acids. The study evaluates the performance of a 100% immobilized polar phase column tailored for FAME analysis.

Methodology

Sample preparation involves converting oil-bound fatty acids into methyl esters. A 1 μL aliquot of soya bean oil methyl esters is introduced into the GC system under split injection conditions. The temperature is held at 185 °C to optimize separation without excessive thermal degradation. Helium serves as the carrier gas at 130 kPa, ensuring sharp peaks and minimal diffusion. The run parameters are designed to maximize resolution of cis/trans isomers and longer-chain fatty acids.

Used Instrumentation

• Gas chromatograph with capillary inlet system
• Agilent CP-Select CB for FAME column, 0.25 mm × 50 m fused silica WCOT (Part no. CP7419)
• Split injector (1:100), 250 °C
• Flame ionization detector (FID), 250 °C
• Helium carrier gas at 130 kPa (1.3 bar)

Main Results and Discussion

The CP-Select CB column achieved baseline separation of 12 FAME peaks, including saturated (C16:0, C18:0, C20:0, C22:0), monounsaturated (C18:1 cis/trans), diunsaturated (C18:2 cis/trans), and triunsaturated (C18:3 cis/trans) isomers. High immobilization of the polar phase supported repeated splitless and on-column injections without loss of efficiency, and stable operation up to 290 °C enabled rapid column bake-out. Low column bleed enhanced sensitivity for trace components. The greater loadability of the CP-Select CB phase (approximately threefold higher than comparable polar columns) improved peak shapes for closely eluting isomers.

Benefits and Practical Applications

This method offers several advantages for routine lipid analysis laboratories:

• Robust and repeatable separation of cis/trans and positional isomers
• Extended column lifetime with minimal performance loss
• Enhanced sensitivity for low-abundance fatty acids when coupled with FID or MS detectors
• Streamlined analysis suitable for quality assurance, regulatory compliance, and research applications

Future Trends and Possibilities

Advances in stationary phase design and detector technology will further refine FAME analysis. Hybrid GC–MS systems combined with high-throughput sample automation promise faster turnaround times and deeper profiling of minor lipid constituents. Emerging techniques in comprehensive two-dimensional GC (GC×GC) may unlock even finer resolution of coeluting isomers, supporting detailed nutritional and metabolic studies.

Conclusion

The described GC–FID method using the Agilent CP-Select CB column provides a reliable, high-resolution approach for FAME analysis in soya bean oil. Its stability, low bleed, and high loadability make it well suited for both routine quality control and advanced research settings.