An alternative approach for ASTM D-7845 in determining chemical species in marine fuel oil by GCMS-QP2020 NX

Importance of the Topic

Marine fuel oils contain varied heavy hydrocarbons and phenolic compounds that pose environmental hazards and potential engine damage. Accurate quantification of these species is critical for regulatory compliance, quality control, spill response and ensuring marine engine longevity.

Objectives and Study Overview

This work presents an alternate approach to ASTM D-7845 using Shimadzu GCMS-QP2020 NX. The method aims to simplify the standard multidimensional GC-MS procedure, reduce cost and instrument complexity, while maintaining sensitivity and compliance with method limits for 30 target analytes in marine fuel oil.

Instrumentation

The key equipment included:

• Shimadzu GCMS-QP2020 NX with UFMS and FASST capabilities
• Split/splitless injector 300 °C, split ratio 30
• SH-Rxi-1ms pre-column (30 m×0.25 mm, df 0.25 μm)
• Rxi-5ms analytical column (60 m×0.32 mm, df 0.50 μm)
• Auxiliary advanced pressure control unit and T-junction for backflushing
• Helium carrier gas

Methodology

Sample and calibration standards were prepared in toluene with ethylbenzene d-10 as internal standard. Five calibration levels 10–1000 ppm were analyzed under simultaneous scan/SIM mode using FASST. Backflush time was optimized at 28.5 min by monitoring hexadecane retention. Data acquisition employed one target and two reference ions per analyte.

Main Results and Discussion

All 30 analytes exhibited linearity coefficients R² above 0.98. The method successfully quantified target compounds, with sample analysis revealing 200 ppm of dibutyl ether. FASST mode enabled simultaneous targeted quantification and untargeted screening, enhancing confidence through spectral library matching.

Practical Applications and Benefits

• Cost-effective alternative to traditional D-7845 without PTV, FID or Dean switch
• High sensitivity and trace-level detection via UFMS
• Simultaneous targeted and untargeted analysis for contaminant screening
• Suitable for QA/QC, environmental monitoring and fuel quality assessment

Future Trends and Potential Uses

Advances may include real-time on-board fuel analysis, integration with high-resolution MS, automated data processing and application to diverse fuel matrices. Coupling with AI-driven interpretation could further enhance rapid decision-making in marine operations.

Conclusion

The described GCMS-QP2020 NX method provides a streamlined, robust and sensitive alternative for ASTM D-7845 compliance, facilitating comprehensive profiling of marine fuel oil species in a cost-effective workflow.

References

ASTM D-7845-17 Standard Test Method for Determination of Chemical Species in Marine Fuel Oil by Multidimensional Gas Chromatography/Mass Spectrometry