Simulated Distillation by High Temperature Gas Chromatography Based on ASTM D7500

Significance of the Topic

Petroleum fractions such as base oils and lubricants are complex mixtures whose performance, pricing and quality control depend critically on accurate boiling range distribution data. Simulated distillation by high-temperature gas chromatography (SIMDIS GC) defined by ASTM D7500 offers a fast, reproducible approach to obtain detailed distillation curves for samples with initial boiling points above 100 °C and final boiling points up to 735 °C.

Objectives and Study Overview

This study demonstrates the application of ASTM D7500 on the Nexis GC-2030 system equipped with the new OCI-2030 NX injection unit to characterize lubricating oil samples. It covers system setup, calibration procedures, sample analysis, performance verification and report generation using LabSolutions™ SIMDIS GC Software.

Methodology and Used Instrumentation

Samples, including calibration mixes (Polywax 655 and n-alkanes standards) and reference material 5010, were prepared in carbon disulfide and cyclohexane. The GC conditions followed ASTM D7500:

• Injector temperature: 100 °C ramped to 430 °C at 15 °C/min
• Column: Ultra ALLOY-SIMDIS(HT) 5 m × 0.53 mm, df 0.1 μm
• Oven program: 35 °C to 430 °C at 10 °C/min, hold 10 min
• Carrier gas: Helium constant flow 19 mL/min
• FID: 450 °C with He makeup (24 mL/min), H2 (32 mL/min), air (200 mL/min)
• Injection volume: 0.6 μL via OCI-2030 NX

LabSolutions SIMDIS GC Software was used for acquisition, peak integration (i-PeakFinder), calibration, and report generation.

Main Results and Discussion

System performance checks with calibration mixes yielded:

• Resolution of C50/C52 peaks: 2.5 (meeting 2–4 standard)
• Peak skewness for C12–C110 between 0.8–1.8 (equivalent tailing factor 0.778–1.125)

The retention time vs boiling point calibration curve was linear across C16–C110. Reference oil analysis matched accepted boiling point distributions within specified tolerances (±3–18 °C). Lubricating oil samples produced clear chromatograms and distillation curves consistent with ASTM criteria.

Benefits and Practical Application of the Method

Key advantages include:

• Rapid, accurate boiling range profiles for quality control and formulation
• Automated calibration and distillation curve generation via LabSolutions SIMDIS GC Software
• Enhanced peak detection and skewness calculation using i-PeakFinder
• Full report customization for routine testing and regulatory compliance

Future Trends and Opportunities

Advancements may include integration of machine learning algorithms for real-time peak deconvolution, development of higher temperature-stable column materials for extended boiling range analyses, miniaturized on-site SIMDIS GC systems, and coupling with mass spectrometry for compositional identification alongside boiling point data.

Conclusion

The Nexis GC-2030 with OCI-2030 NX successfully performed simulated distillation of lubricating oil according to ASTM D7500. System performance, calibration linearity, and reference oil reproducibility all met standard requirements. LabSolutions SIMDIS GC Software streamlines data processing and reporting, supporting efficient quality control workflows.

References

• Shimbo E., Nagao Y. Simulated Distillation by High Temperature Gas Chromatography Based on ASTM D7500. Shimadzu Application News, First Edition Sep 2021.
• ASTM International. ASTM D7500-21: Standard Test Method for Determination of Boiling Range Distribution of Petroleum Fractions by Gas Chromatography. 2021.