ASTM D6730 Detailed Hydrocarbon Analysis of Spark Ignition Fuel using Zebron™ ZB-DHA-PONA Gas Chromatography Column

Importance of the Topic

The detailed analysis of hydrocarbon group types in spark-ignition fuels is essential for meeting stringent emission regulations, ensuring engine performance and optimizing refinery blending operations. Accurate quantification of paraffins, isoparaffins, olefins, naphthenes and aromatics supports both regulatory compliance and process control.

Objectives and Overview of the Study

This study evaluates the performance of Zebron™ ZB-DHA-PONA gas chromatography columns in accordance with ASTM D6730-01 for detailed hydrocarbon analysis (DHA) of spark-ignition engine fuels. It aims to demonstrate resolution, efficiency and reproducibility in quantifying 29 representative fuel components, including oxygenates.

Methodology and Instrumentation Used

The analysis employs gas chromatography with flame ionization detection under the following conditions:

• Primary column: 100 m × 0.25 mm × 0.50 µm Zebron ZB-DHA-PONA (100 % dimethylpolysiloxane)
• Tuning precolumn: 5 m × 0.25 mm × 1.0 µm ZB-DHA-PONA-TUNE (5 % phenyl, 95 % dimethylpolysiloxane)
• Carrier gas: Hydrogen at 2 mL/min (constant flow)
• Injection: Split ratio 150:1 at 200 °C, injection volume 0.2 µL
• Oven program: 30 °C (8.5 min), ramp to 48 °C at 22 °C/min (27 min), to 141 °C at 3 °C/min (1 min), to 275 °C at 1 °C/min (2 min)
• Detection: Flame ionization detector at 275 °C

Used Instrumentation

• Gas chromatograph with FID
• Zebron ZB-DHA-PONA GC columns (multiple lengths and film thicknesses)
• Zebron ZB-DHA-PONA-TUNE precolumn
• ZebronPLUS Straight Z-Liner™ for split injection
• Hydrogen supply or generator

Main Results and Discussion

The dual-column configuration delivered baseline separation of 29 key components, with column efficiency exceeding 400,000 theoretical plates for pentane, surpassing ASTM D6730-01 requirements. Critical pairs such as benzene/toluene and cycloalkanes/aromatics were well resolved. The Engineered Self Cross-linking™ stationary phase maintained low bleed and stable performance up to 360 °C, yielding symmetric peaks across both polar and nonpolar analytes.

Benefits and Practical Applications of the Method

• Regulatory compliance through accurate PONA quantification
• Refinery quality control and blending optimization
• Reliable detection of oxygenates and polar additives
• High throughput enabled by robust column stability and efficiency

Future Trends and Applications

Future developments may include coupling DHA columns with mass spectrometry for unambiguous compound identification, deployment of compact GC systems for on-site analysis, integration of chemometric data analysis tools and adaptation of methods for bio-blends and synthetic fuels. Ongoing innovation in column chemistries and detection technologies will expand analytical capabilities and support sustainability goals.

Conclusion

The Zebron ZB-DHA-PONA series offers high-resolution separation of spark-ignition fuel components in line with ASTM D6730-01. Its optimized stationary phases and column geometries provide reliable quantitation of hydrocarbons and oxygenates, meeting both regulatory and process control requirements.

References

• ASTM D6730-01: Standard Test Method for Detailed Hydrocarbon Analysis of Spark-Ignition Engine Fuels