Analysis of FAME in butter

Significance of the topic

Accurate profiling of fatty acid methyl esters (FAME) in butter is vital for assessing product quality, verifying authenticity and monitoring nutritional attributes. High-resolution separation of FAME enables reliable quantification of individual fatty acids, which is critical for food testing laboratories, research and quality assurance in the dairy industry.

Objectives and overview

This application note demonstrates the use of a 100% bonded polar GC column (Agilent CP-Select CB for FAME) coupled with flame ionization detection (FID) to achieve robust, high-resolution separation of FAME derived from butter. The study highlights column stability, loadability and suitability for routine split or on-column injections without loss of performance.

Instrumentation

• Gas chromatograph with capillary column capability
• Column: Agilent CP-Select CB for FAME, 0.25 mm internal diameter × 50 m fused silica WCOT
• Carrier gas: helium at 130 kPa (1.3 bar)
• Injector: split mode (1:100), temperature 250 °C
• Detector: flame ionization detector (FID), temperature 250 °C

Methodology

Butter samples were converted to methylesters and 1 µL aliquots were injected. The column was held isothermal at 185 °C to optimize separation of saturated and unsaturated FAME. Helium carrier gas provided low column bleed and consistent peak shapes, while the high thermal stability (up to 290 °C) of the bonded polar phase allowed rapid bake-out cycles between runs.

Main results and discussion

The method resolved twenty FAME components ranging from C6:0 to C18:2 isomers. Key observations:

• The CP-Select CB column delivered comparable selectivity to CP-Sil 88 with the advantage of higher mechanical and thermal stability.
• Loadability was at least three times greater than traditional polar phases, improving resolution of closely eluting isomers.
• Low column bleed enhanced quantification of trace FAME, particularly when paired with sensitive detectors.

Benefits and practical applications

• Robust column performance enables extensive sample throughput without loss of resolution.
• Enhanced stability reduces downtime and maintenance costs in routine food testing environments.
• High sensitivity and reproducibility support regulatory compliance and nutritional labeling.

Future trends and possibilities of application

Advances in GC stationary phases and integration with mass spectrometry will further improve detection limits and structural elucidation of minor FAME components. Automation of sample preparation and coupling with chemometric tools will streamline authenticity testing and adulteration detection in dairy products.

Conclusion

The Agilent CP-Select CB for FAME column combined with GC-FID provides a reliable, high-resolution method for butter FAME analysis. Its exceptional stability, low bleed and high loadability make it an ideal choice for laboratories seeking reproducible, high-throughput fatty acid profiling.