Determination of Aromatic Hydrocarbons in Aviation Fuel with the Agilent 1260 Infinity Binary LC System with RI Detection According to IP436/ASTM D6379

Importance of the Topic

The accurate quantification of aromatic hydrocarbons in aviation fuels is essential for ensuring fuel performance, regulatory compliance and environmental impact management.
Aromatic content directly affects combustion efficiency, emission characteristics and material compatibility in aircraft engines.

Objectives and Overview of the Study

This work demonstrates the application of the Agilent 1260 Infinity Binary LC System with refractive index detection for the determination of mono-aromatic (MAH) and di-aromatic hydrocarbons (DAH) in jet fuel according to IP436/ASTM D6379.
The method covers boiling range fractions from 50 to 300 °C and establishes calibration, sensitivity and precision benchmarks.

Methodology and Instrumentation

Sample Preparation

• Weigh 4.9–5.1 g of fuel into a 10 mL volumetric flask and dilute to volume with HPLC-grade n-heptane.
• Allow to settle for 10 minutes and filter to remove insoluble residues.

Chromatographic Conditions

• Column: ZORBAX NH2 analytical column (4.6 × 250 mm, 5 μm) with matching guard cartridge.
• Mobile Phase: n-Heptane at 1.0 mL/min.
• Temperature: Column and detector at 35 °C; autosampler at 10 °C.
• Injection Volume: 10 μL; total run time 15 minutes.
• Valve Configuration: Forward flush (positions 1 & 6) for sample loading and separation; backflush capability for matrix removal.

Instrumentation

• Agilent 1260 Infinity Binary Pump with integrated degasser.
• Agilent 1260 Infinity Standard Autosampler and Thermostat.
• Agilent 1260 Infinity Column Compartment with Quick-Change valve.
• Agilent 1260 Infinity Refractive Index Detector.
• Data acquisition via Agilent OpenLAB CDS ChemStation Edition.

Key Results and Discussion

System Performance Standard containing cyclohexane, o-xylene and 1-methyl naphthalene showed clear elution at ~3.55, 4.87 and 6.78 minutes respectively.
Calibration curves for o-xylene (MAH) and 1-methyl naphthalene (DAH) exhibited excellent linearity with correlation coefficients above 0.9999 over 0.01–1.5% and 0.005–0.5% concentration ranges.
Precision tests including valve switching and backflush yielded retention time RSD below 0.1% and area RSD below 0.2%.
The method detection limit was determined to be below 1 μg/mL for aromatic analytes (S/N = 3).

Benefits and Practical Applications of the Method

This normal-phase HPLC-RI approach provides a robust, solvent-simple protocol for routine QA/QC of aviation fuels.
It meets industry standards for aromatic content determination and supports decision-making in fuel formulation, process optimization and regulatory reporting.

Future Trends and Opportunities

Emerging directions include coupling with mass spectrometry for improved specificity, application of UHPLC for faster throughput, green solvent alternatives and integration of automated data processing using advanced algorithms.
Expanding the method to include polyaromatic profiling and real‐time monitoring platforms can further enhance fuel analysis capabilities.

Conclusion

The Agilent 1260 Infinity Binary LC System with RI detection fulfills IP436/ASTM D6379 requirements for aromatic hydrocarbon analysis in jet fuels.
The demonstrated method offers high sensitivity, precision and linearity, making it a reliable tool for fuel quality assessment.

References

1. ASTM D6379 11 Standard Test Method for Determination of Aromatic Hydrocarbon Types in Aviation Fuels and Petroleum Distillates by HPLC with RI Detection ASTM International 2011
2. Agilent Technologies Application Note 5991-3170EN Determination of Aromatic Hydrocarbons in Petroleum Middle Distillates with the Agilent 1260 Infinity Binary HPLC System and RI Detection According to IP391(2000)/ASTM D659 2013
3. Agilent Technologies Application Note 5991-3171EN Determination of Total Aromatic Hydrocarbons and Total Saturates with the Agilent 1260 Infinity Binary LC System with RI Detection According to ASTM D7419 2014