GC/MS Analysis of Trace Fatty Acid Methyl Esters (FAME) in Jet Fuel Using Energy Institute Method IP585

Significance of the Topic

The incorporation of biodiesel-derived fatty acid methyl esters (FAME) into multi‐product pipelines poses a risk of contaminating aviation turbine fuel with trace levels of these polar compounds. As the Joint Inspection Group limits FAME in jet fuel to 5 mg/kg, sensitive and selective analytical methods are essential for quality control and regulatory compliance. GC/MS techniques leveraging selective ion monitoring enable reliable detection of low‐level FAME amidst a complex hydrocarbon matrix.

Study Objectives and Overview

This application note presents the evaluation of Energy Institute Method IP585 on an Agilent 5975C GC/MS system for quantifying six representative FAME compounds (C16:0 to C18:3) in jet fuel. The goals were to establish calibration linearity from 2 to 100 mg/kg, assess spike recoveries over 1–40 mg/kg, and verify precision relative to method performance criteria.

Methodology and Instrumentation

The method employs simultaneous selective ion monitoring (SIM) and full scan (SCAN) acquisitions for enhanced selectivity and confirmation. Calibration standards were prepared from bulk FAME solutions and internal standard methyl heptadecanoate‐d33. Jet fuel samples were spiked at defined levels and fortified with internal standard. Key instrument configuration:

• Gas chromatograph: Agilent 7890A with splitless inlet, HP-INNOWAX capillary column (50 m×0.2 mm×0.4 µm)
• Mass spectrometer: Agilent 5975C MSD with inert EI source, tuned by AUTOTUNE
• Autosampler: Agilent 7693A ALS for 1 µL injections
• Carrier gas: helium at 0.6 mL/min constant flow
• GC oven program: 150 °C (5 min) → 200 °C @12 °C/min (17 min) → 252 °C @3 °C/min (6.5 min)
• MS conditions: 70 eV EI, source 230 °C, quadrupole 150 °C, scan range m/z 33–320, SIM dwell 50 ms for target ions

Main Results and Discussion

Calibration performance exceeded method requirements, with linear regression coefficients (R²) above 0.99 for both low (2–10 mg/kg) and high (20–100 mg/kg) ranges. Total ion chromatograms and SIM overlays confirmed clear separation of six FAME peaks and negligible background. Matrix‐induced retention time shifts (up to 0.3 min for C16:0) were monitored and corrected via SIM window scheduling. Spike recoveries in jet fuel were quantitative across 1, 5, 10, and 40 mg/kg levels, and repeatability (r) was three to ten times better than IP585 criteria. Analysis of a commercial sample yielded 3.3 mg/kg total FAME with excellent duplicate precision.

Benefits and Practical Applications

This GC/MS approach offers:

• High sensitivity and selectivity for low‐level FAME in complex matrices
• Robust calibration over a wide concentration range
• Rapid confirmation of peak identity via combined SIM/SCAN data
• Reproducible quantification meeting or exceeding industry standards

This method supports fuel producers, pipeline operators, and quality laboratories in monitoring biodiesel contamination in aviation fuel.

Future Trends and Potential Applications

Advancements may include automated data processing with real‐time quality checks, broader compound libraries for emerging biofuel blends, and integration with high‐throughput platforms. Coupling GC/MS with orthogonal techniques such as GC×GC or high‐resolution MS could further enhance resolution of trace contaminants in complex fuel samples.

Conclusion

The Agilent 5975C GC/MS system effectively implements Energy Institute Method IP585 for trace FAME analysis in jet fuel. The method demonstrated excellent linearity, full recovery, and superior precision, affirming its suitability for routine quality control of aviation turbine fuels.

Reference

IP 585/10 “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”, The Energy Institute, London