Determination of Hydrocarbon Components in Petroleum Naphthas

Importance of the Topic

This summary addresses the characterization of hydrocarbon composition in petroleum naphthas using fast GC-TOFMS analysis. Understanding detailed naphtha composition is critical for refinery process control, product quality assessment, regulatory compliance, and mathematical modeling of refining operations.

Objectives and Study Overview

The study aimed to implement and adapt ASTM D5134 on a LECO Pegasus GC-TOFMS platform to achieve rapid, accurate profiling of a PIANO standard mix and industrial naphtha samples. Key goals included:

• Reducing analysis time compared to the 122.5 min standard method
• Maintaining or improving resolution and quantitative accuracy
• Confirming spectral deconvolution capability for coeluting compounds

Methodology and Instrumentation

The modified method employed:

• LECO Pegasus GC-TOFMS operating in EI mode
• GC conditions: Supelco SPB-1 column (30 m × 0.25 mm × 0.25 μm), injector 225 °C, split 400:1, constant flow 1.8 mL/min
• Oven program: 40 °C (2 min) to 250 °C at 10 °C/min (2 min hold)
• Acquisition: mass range 45–450 amu, 25 spectra/s (up to 500 spectra/s capability)

Main Results and Discussion

The high acquisition rate and spectral continuity enabled accurate definition of narrow peaks and automated deconvolution of complex coelutions. Highlights include:

• Five-fold reduction in run time (122.5 min to 25 min) for ASTM D5134
• Effective deconvolution of coeluting analytes, including those sharing m/z values
• Accurate area percentage and retention index calculations without extended chromatographic separation
• Identification of 170 components in a naphtha column load sample and 152 components in a bottom sample at S/N ≥ 200

Benefits and Practical Applications

The approach delivers:

• Enhanced laboratory throughput and productivity
• Reliable quantitative data aided by response factor correction
• Improved confidence in complex mixture analysis for petrochemical QA/QC
• Automated data handling: peak finding, deconvolution, library search, and reporting

Future Trends and Applications

Potential developments include:

• Further acceleration of chromatography with ultra-fast modulation
• Real-time process monitoring using inline GC-TOFMS
• Advanced chemometric algorithms for pattern recognition
• Extension to other complex matrices (biofuels, environmental samples)

Conclusion

The LECO Pegasus GC-TOFMS platform, combined with modified ASTM D5134 parameters, achieves rapid, high‐resolution analysis of petroleum naphthas. Fast spectral acquisition and continuity underpin robust deconvolution and quantification, offering significant gains in analytical speed and data quality.