Determination of aliphatic and aromatic contents in aviation kerosene by GC-VUV

Significance of the Topic

The composition of aviation kerosene, particularly its aromatic hydrocarbon content, directly influences fuel performance, emission profiles, and material compatibility in gas turbine engines. Rapid and reliable quantification of aliphatic and aromatic fractions supports quality control, regulatory compliance, and environmental impact assessment.

Study Objectives and Overview

This study proposes a gas chromatography–vacuum ultraviolet (GC-VUV) method, aligned with ASTM D8267, to quantify aliphatic, total aromatic, monoaromatic, and diaromatic hydrocarbons in aviation kerosene. The goal is to achieve a complete analysis within 14 minutes while maintaining high accuracy and repeatability.

Methodology and Instrumentation

The analytical system consisted of a Shimadzu GC-2030 gas chromatograph coupled with a VGA-101 VUV detector. Separation was performed on an SH-Rtx-1 column (30 m×0.25 mm×0.25 μm) under the following conditions:

• Oven program: 50 °C (0.1 min) to 260 °C at 15 °C/min
• Carrier pressure: 139.9 kPa, flow rate: 2 mL/min
• Injector: split mode (100:1), temperature 250 °C, injection volume 1 μL
• Transfer line and flow cell: 275 °C; makeup gas pressure 0.35 psi
• Spectral range: 125–430 nm at 4 Hz acquisition

Data processing utilized VUVision for spectrum library matching and VUVAnalyze software with time interval deconvolution (TID) to resolve coeluting species.

Main Results and Discussion

The method delivered complete hydrocarbon class separation and identification via characteristic VUV absorption spectra. A representative kerosene sample yielded:

• Aliphatic hydrocarbons: 82.5 % mass fraction
• Total aromatics: 17.5 % mass fraction (monoaromatic 17.4 %, diaromatic 0.06 %)

The repeatability test (n=5) showed relative standard deviations below 1 % for both mass and volume fractions, confirming robust precision.

Benefits and Practical Applications

• Significantly reduced analysis time compared to fluorescent indicator adsorption (ASTM D1319).
• Minimal chromatographic separation requirements due to spectral deconvolution.
• Fully automated identification and quantification, enhancing laboratory throughput.
• Applicable for routine QA/QC of aviation fuels and compliance with emerging regulatory standards.

Future Trends and Applications

Advancements may include expanding VUV spectral libraries for broader fuel types, integrating real-time monitoring in production lines, coupling GC-VUV with other detectors for comprehensive fingerprinting, and development of portable VUV systems for field analysis.

Conclusion

The proposed GC-VUV method, adhering to ASTM D8267, achieves rapid (14 min), accurate, and repeatable measurement of hydrocarbon classes in aviation kerosene. Its automated spectral identification and TID-based separation make it a powerful tool for modern fuel analysis.

References

• ASTM D8267 – Standard Test Method for Determination of Total Aromatic, Monoaromatic, and Diaromatic Content of Aviation Turbine Fuels Using GC-VUV.
• Shimadzu Corporation, SGC-ADS-0191 – System Gas Chromatograph Application Note.