Analysis of Biodiesel Fatty Acid Methyl Esters (FAME) in Aviation Jet Fuels Using Method IP 585

Significance of the Topic

Accurate determination of biodiesel fatty acid methyl esters (FAME) in aviation jet fuels is vital to prevent contamination that can impair low-temperature performance and oxidative stability. By maintaining FAME levels below regulated limits, aircraft safety and engine reliability are ensured.

Objectives and Study Overview

This study applies Energy Institute Method IP 585 to quantify FAME in jet fuel using a polar capillary GC column and GC-MS in selective ion monitoring (SIM) mode. The goals were to validate calibration linearity, assess recovery in fortified jet samples, and demonstrate that a Stabilwax column effectively separates FAME from hydrocarbon matrix interferences.

Methodology

Calibration standards spanning 2–100 mg/kg FAME were prepared in n-dodecane with methyl heptadecanoate-d33 as internal standard. Jet fuel samples were analyzed neat and fortified at 36, 60, and 120 mg/kg. Soy biodiesel B100 was also spiked into jet fuel and isooctane at 85 mg/kg to evaluate isomer separation.

Instrumentation Used

• GC-MS system: Agilent 7890B GC with 5977A MSD
• Column: Restek Stabilwax, 60 m × 0.25 mm × 0.50 µm
• Injection: Splitless 1 µL, inlet 260 °C, purge 100 mL/min after 1 min
• Carrier gas: Helium, 0.8 mL/min constant flow
• Oven program: 150 °C (5 min), 12 °C/min to 200 °C (17 min), 3 °C/min to 252 °C (3 min)
• MS conditions: EI source 300 °C, quadrupole 180 °C, scan 33–320 amu, SIM with target ions for C16:0–C18:3

Main Results and Discussion

Calibration curves for each FAME component (2–10 mg/kg low level and 20–100 mg/kg high level) met linearity criteria (R²>0.997, R>0.998). Recovery experiments in fortified jet fuel showed deviations within ±5%, confirming method accuracy. Minor retention time shifts in jet fuel due to hydrocarbon focusing were effectively managed by SIM detection. Methyl oleate cis/trans isomers were resolved and combined per IP 585 guidance. Background contamination of 1.5 mg/kg C18:1 in neat jet fuel was subtracted from fortified results.

Benefits and Practical Applications

• Ensures compliance with the 50 ppm FAME limit in commercial jet fuels.
• Rapid, reliable screening for pipeline cross-contamination monitoring.
• Applicability to quality control laboratories in aviation fuel production and distribution.

Future Trends and Potential Applications

Advances may include coupling high-resolution MS for even lower detection limits, automated sample preparation to increase throughput, and adaptation to biofuel blends in alternative aviation fuels. Portable GC-MS platforms could enable on-site pipeline monitoring and rapid field analysis.

Conclusion

Method IP 585 with a stabilwax GC column and GC-MS in SIM mode provides a robust approach for detecting and quantifying biodiesel FAME in aviation jet fuels. The method meets regulatory requirements, demonstrates high linearity and recovery, and effectively distinguishes FAME from complex hydrocarbon matrices.

References

• Energy Institute. IP 585: Determination of fatty acid methyl esters (FAME) derived from bio-diesel fuel in aviation turbine fuel—GC-MS with selective ion monitoring/scan detection method. January 2010.