Group-Type Analysis of Jet Fuel Using the Agilent Flow-Modulated GC×GC-FID

Significance of the Topic

In aviation turbine fuel quality, understanding aromatic composition is critical for safety, performance, and regulatory compliance. Conventional one-dimensional gas chromatography and spectroscopy lack the selectivity to resolve the complex mixture of hydrocarbon isomers in jet fuels. Comprehensive two-dimensional gas chromatography with flame ionization detection (GC×GC-FID) provides enhanced separation power, sensitivity, and reproducible quantification, enabling detailed profiling of mono- and diaromatic species according to stringent standards.

Objectives and Study Overview

This study applies an Agilent 8890 reverse fill/flush flow-modulated GC×GC-FID system to perform group-type analysis of jet fuel in accordance with China’s NB/SH/T 6078-2023 standard. The goals include determining the relative abundance and carbon number distribution of 1-ring and 2-ring aromatic hydrocarbons, and assessing the system’s repeatability, linearity, sensitivity, and quantitative precision for routine laboratory use.

Methodology and Instrumentation

The analytical approach involved direct injection of jet fuel samples and gravimetric standards without pretreatment. Three different column configurations were evaluated to optimize resolution and analysis time:

• Primary columns: nonpolar DB-1 (20 or 40 m, 0.18 mm id), ultra-narrow DB-1 (20 m, 0.10 mm id) with hydrogen carrier for enhanced efficiency.
• Secondary columns: polar DB-HeavyWAX (5 m, 0.32 mm id) and midpolar DB-17ht (5 m, 0.25 mm id) for orthogonal separation.
• Flow modulator: Agilent reverse fill/flush differential flow modulator (RFM) installed in the GC oven, no moving parts, modulation period of 3–4 s.
• Detector: Flame ionization detection with high acquisition rate (200 Hz).

Used Instrumentation

• Agilent 8890 GC×GC-FID system with split/splitless inlet.
• Agilent Capillary Flow Technology reverse flow modulator.
• Columns: DB-1, DB-HeavyWAX, DB-17ht; deactivated fused silica for monitoring.
• Software: Agilent OpenLab CDS 3.7 for acquisition; GC Image GC×GC Edition for data processing.

Results and Discussion

• Retention Time Repeatability: 1D RT RSD ~0%, 2D RT RSD ≤ 0.27% across 10 injections; allows stable template-based peak identification.
• Quantitative Precision: Area RSD < 2% for nontrace aromatics; normalized area RSD < 1% for most components.
• Linearity: Calibration of 12 individual aromatics and six aggregate groups over eight levels yielded R² > 0.999; recoveries 98–114%.
• Group Quantification: Two refinery jet fuels showed distinct aromatic profiles, with repeatability (n = 10) RSD < 4% even at low benzene levels (0.001 % w).
• Column Optimization: Thinner film and narrower id columns with hydrogen carrier gas dramatically improved resolution and reduced analysis time while preserving separation of saturates, monoaromatics, and diaromatics.

Benefits and Practical Applications

The described GC×GC-FID methodology delivers:

• Comprehensive profiling of jet fuel aromatics for regulatory compliance and quality control.
• High resolution and sensitivity for trace-level detection without sample pretreatment.
• Robust and easy-to-maintain flow modulation suitable for laboratories with limited GC×GC expertise.
• Data reproducibility enabling routine use in industrial and research settings.

Future Trends and Applications

Ongoing developments may include:

• Automation of data analysis workflows with advanced pattern recognition in GC×GC software.
• Integration with mass spectrometry for structural elucidation of unknown isomers.
• Application to alternative and sustainable aviation fuels to evaluate composition and performance.
• Miniaturized or on-site GC×GC platforms for rapid field screening.

Conclusion

The Agilent reverse flow-modulated GC×GC-FID system achieves exceptional separation, repeatability, and quantitative performance for group-type analysis of jet fuel aromatics according to NB/SH/T 6078-2023. Its robustness and ease of use make it well suited for routine laboratory implementation, enhancing fuel quality assessment and regulatory compliance.

References

1. China State Administration for Market Regulation. NB/SH/T 6078-2023: Determination of Benzene and Naphthalene Hydrocarbons in Jet Fuel by Comprehensive Two-Dimensional Gas Chromatography.
2. Agilent Technologies. Agilent Reversed Flow Modulator. Technical Overview 5994-0157EN, 2018.
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