GCC: Use of Thermo Scientific Trace GC for ASTM D2887 Accelerated Procedure with Alternative Carrier Gases

Significance of the Topic

This application note evaluates the accelerated ASTM D2887b gas chromatography procedure for boiling point distribution of petroleum samples using the Thermo Scientific Trace GC. Fast temperature ramping and alternative carrier gases support higher sample throughput, reduced analysis time and operational flexibility in fuel and petrochemical quality control.

Objectives and Study Overview

• Assess the Trace GC performance under the accelerated D2887b ramp rate (35 °C/min) across the full oven range.
• Compare helium, hydrogen and nitrogen carrier gases for retention time accuracy and boiling point determination.
• Validate results against the standard D2887a method using helium at 15 °C/min.

Instrumentation Used

• Gas chromatograph: Thermo Scientific Trace GC configured for high-rate oven ramps.
• Column: 10 m × 0.53 mm ID × 0.88 µm PDMS phase.
• Detectors: Flame ionization detectors on front and back positions for retention profiling.
• Carrier gases and flows: Helium 26 mL/min, hydrogen 35 mL/min, nitrogen 35 mL/min.
• Injection: 0.1 µL neat hydrocarbon mixture (C5–C44) and reference gas oil.

Methodology and Instrumentation

• Oven program: ramp from initial temperature (60 °C for helium; 40 °C for hydrogen and nitrogen) to 360 °C at 35 °C/min.
• Verification: Confirm linear ramp capability for the full temperature range; adjust to the highest achievable linear rate if 35 °C/min is not attainable.
• Data acquisition: Record retention times for n-alkanes C5–C44 and standard distillation points (IBP through FBP).

Main Results and Discussion

• Chromatograms demonstrate clear separation of C5–C44 with compressed run times (approx. 20 min).
• Retention time shifts between carrier gases remain small and predictable: hydrogen shows slightly faster elution, nitrogen slightly slower compared to helium.
• Calculated boiling point distribution points (IBP, 5 %, 10 %, …, 95 %, FBP) for all gases fall within ±5 °C of reference values, meeting ASTM acceptance criteria.
• Precision across replicate injections remains within specification for all gases, confirming method robustness.

Benefits and Practical Applications

• High throughput: Accelerated ramp nearly halves analysis time versus standard D2887a.
• Carrier gas flexibility: Hydrogen offers speed benefits; nitrogen provides cost savings where helium is limited.
• Quality control: Reliable boiling point distribution supports petroleum product specification, blending control, and feedstock evaluation.

Future Trends and Potential Applications

• Integration of ultra-fast columns and advanced stationary phases for sub-10 min runs.
• Automated ramp verification and oven diagnostics to ensure consistent performance over instrument lifetime.
• Data processing enhancements with machine learning for more accurate boiling point predictions and trend monitoring.
• Expansion to alternative energy feedstocks, biodiesel, and pyrolysis oils using similar rapid GC approaches.

Conclusion

The Thermo Scientific Trace GC successfully executes the ASTM D2887 accelerated procedure with helium, hydrogen and nitrogen carrier gases. All configurations achieve acceptable retention accuracy and boiling point distribution within ASTM limits, offering laboratories a flexible, high-throughput solution for petroleum analysis.

References

• ASTM D2887 Standard Test Method for Boiling Range Distribution of Petroleum Fractions by Gas Chromatography.