Analysis of Free Fatty acids - No. 506

Significance of the Topic

Free fatty acids are key indicators of food quality, nutritional value, and lipid stability. Accurate profiling of these compounds supports quality control in food science, nutritional research, and industrial analytics.

Objectives and Study Overview

This application note demonstrates a robust method for the separation and quantification of thirteen free fatty acids ranging from butyric acid (C4:0) to behenic acid (C22:0) using gas chromatography coupled with flame ionization detection (GC-FID) on a polar stationary phase.

Methodology and Instrumentation

Instrumentation used:

• Gas chromatograph equipped with a flame ionization detector (FID)
• SH-PolarD capillary column (30 m × 0.32 mm I.D., film thickness 0.25 µm)

Analytical conditions:

• Column temperature program: 40 °C (2 min), ramp at 10 °C/min to 250 °C, hold 15 min
• Injection: 1 µL splitless mode (hold time 0.25 min), injector temperature 250 °C
• Carrier gas: hydrogen at 6.0 mL/min (constant flow); split flow 75 mL/min
• Detector temperature: 250 °C

Main Results and Discussion

The optimized method achieved baseline resolution for all thirteen free fatty acids at a concentration of 100 µg/mL in methanol. Short-chain fatty acids eluted first, followed by medium- and long-chain homologues, illustrating the effectiveness of the polar column in resolving structurally similar compounds.

Benefits and Practical Applications

• High sensitivity and selectivity for free fatty acid analysis
• Reproducible retention times and peak shapes across replicates
• Applicability to food science, nutrition labs, and QA/QC environments

Future Trends and Applications

Emerging directions include coupling GC separation with mass spectrometry for structural elucidation, integrating automated sample preparation for high-throughput workflows, and expanding lipidomics libraries to cover broader lipid classes.

Conclusion

The presented GC-FID protocol on the SH-PolarD column offers a reliable, robust, and sensitive approach for comprehensive free fatty acid profiling, supporting diverse applications in food and industrial analysis.

References

SHIMADZU Corporation. Application Note ERAS-1000-0506: Analysis of Free Fatty Acids by GC-FID with SH-PolarD Column. First Edition, September 2023.