EN 15779 - Gas Chromatographic Analysis of Polyunsaturated FAME in Biodiesel Made From Algae and Marine Oils

Importance of the Topic

Algal and marine oils are emerging nonfood feedstocks for biodiesel production. Their high growth rates and oil yields make them attractive alternatives to vegetable and animal fats. However, elevated levels of polyunsaturated fatty acid methyl esters (PUFA FAMEs) can compromise fuel stability and promote engine fouling if not accurately monitored.

Study Objectives and Overview

This application note evaluates the performance of the EN 15779 gas chromatographic method for quantifying four major PUFA FAMEs in B100 biodiesel derived from algal oil. Two algal biodiesel samples were analyzed in duplicate using an Agilent 7890A GC system configured according to EN 15779 specifications.

Methodology and Instrumentation

The method employs an Agilent 7890A GC with a DB-Wax capillary column (0.32 mm × 30 m, 0.25 μm) and flame ionization detection. Key parameters include:

• Oven program: 150 °C (1 min), 15 °C/min to 200 °C, 2 °C/min to 250 °C
• Inlet: split 50:1, 220 °C, H₂ carrier at 1 mL/min
• FID: 250 °C
• Internal standard: methyl tricosanoate (C23:0)

Sample preparation involved spiking 100 mg biodiesel with 1 mg/mL C23:0 in n-heptane, diluting, and injecting 1 µL. Retention times of C20:4, C20:5, C22:5 and C22:6 FAMEs were established using a reference standard.

Results and Discussion

Chromatograms showed clear separation of the four PUFA FAMEs and the C23:0 internal standard. Quantification used theoretical response factors from EN 15779, corrected by the internal standard signal. Total PUFA contents were 11.08% and 11.11% for sample 1, and 4.93% and 4.98% for sample 2. Repeatability (r) values of 0.03 and 0.05 fell well below the EN 15779 threshold (r ≤ 0.07), demonstrating excellent precision.

Benefits and Practical Applications

• Reliable quantification of PUFA FAMEs ensures compliance with quality standards.
• Helps fuel producers monitor oxidation stability and prevent operational issues.
• The method integrates seamlessly into existing Agilent GC workflows.

Instrumentation Used

• Agilent 7890A GC with split/splitless inlet and EPC control
• Agilent 7693 autosampler
• DB-Wax capillary column (0.32 mm × 30 m × 0.25 μm)
• Flame ionization detector

Future Trends and Opportunities

Emerging research focuses on improving oxidation resistance of PUFA‐rich biodiesel via additive development and feedstock engineering. Advances in high-throughput GC methods and automated data processing will further enhance routine quality control in industrial settings.

Conclusion

The EN 15779 method implemented on an Agilent 7890A GC provides accurate and precise measurement of PUFA FAMEs in algal biodiesel. The approach meets all repeatability criteria and delivers robust results suitable for fuel quality assurance.

References

• EN 15779 Petroleum products and fat and oil derivatives – Fatty acid methyl esters (FAME) for diesel engines – Determination of polyunsaturated fatty acid methyl esters (PUFA) by gas chromatography; CEN, 2009.