Analysis of Gasoline and Alcohol using PONA System

Importance of the Topic

Analysis of complex hydrocarbon mixtures in gasoline is critical for fuel quality control, regulatory compliance, and performance optimization.
PONA (Paraffins, Olefins, Naphthenes, Aromatics) profiling provides detailed composition data that inform octane rating, vapor pressure, and environmental impact assessments.
Recent market trends toward low-alcohol fuels underscore the need for robust methods that can simultaneously quantify hydrocarbons and alcohols under consistent conditions.

Objectives and Study Overview

This study evaluates retention time stability in PONA analysis using a Shimadzu GC-2010 gas chromatograph equipped with a CRG cryogenic module.
It also demonstrates simultaneous separation of gasoline components and various lower alcohols, addressing the growing demand for blended fuel analysis.

Methodology and Instrumentation

The PONA system comprises:

• Shimadzu GC-2010AF gas chromatograph with AOC autosampler and CRG-2010 cryogenic attachment
• GLC-Petrostar capillary column (0.25 mm × 100 m, 0.5 µm film thickness)
• Carrier gas: helium; split ratio: 1:200
• Temperature program: start at 5 °C (7 min), ramp at 2 °C/min to 45 °C (0 min), ramp at 5 °C/min to 200 °C (10 min)
• Software: GCsolution for instrument control and data acquisition; PONAsolution for peak identification, quantitation, and PONA calculations

Main Results and Discussion

Repeatability testing on five injections of identical gasoline samples showed retention time coefficients of variation below 0.01% for key hydrocarbon peaks, reflecting excellent temporal stability.
Chromatograms indicated clear peak separation across the PONA classes, with enlarged sections confirming resolution of closely eluting isomers.
Alcohol standard mixtures (methanol, ethanol, isopropanol, tert-butanol, n-propanol, methyl tert-butyl ether, sec-butanol, isobutanol, benzene, n-butanol) were baseline-separated, with minor overlaps only at high concentrations for specific n-butanol isomers.

Benefits and Practical Applications

• High retention time stability enhances identification accuracy and reduces manual correction time
• Comprehensive PONAsolution software streamlines batch processing and statistical evaluation of fuel properties
• Simultaneous analysis of hydrocarbons and alcohols supports quality control in gasoline blending and alternative fuel development

Future Trends and Potential Applications

• Integration with mass spectrometry for enhanced compound confirmation
• Adoption of multidimensional GC techniques to further resolve complex mixtures
• Expansion to emerging biofuels and synthetic fuel blends
• Automation of data processing using advanced machine learning algorithms

Conclusion

The GC-2010 with cryogenic module demonstrates exceptional retention time stability and separation performance for comprehensive PONA analysis of gasoline and low-alcohol fuels.
This robust platform delivers reliable quantitative and qualitative insights essential for fuel quality control and research in alternative energy sources.