Determination of Chemical Species in Marine Fuel Oil in accordance with ASTM D 7845 by GC-MS

Significance of the Topic

Marine fuel oil is extensively used in shipping engines but is susceptible to contamination by aromatic and oxygenated compounds, which can impair pump performance and increase maintenance costs. Standardizing the quantification of these species is critical for ensuring fuel quality, operational safety and compliance with regulatory specifications such as ASTM D7845.

Objectives and Overview of the Study

This study aimed to validate a GC-MS analytical protocol, based on ASTM D7845, for simultaneous quantitation of 30 target aromatic and oxygenated compounds in marine fuel oil. Using a Shimadzu GCMS-QP2020 NX system, the work assessed sensitivity, linearity, reproducibility, sample analysis and carryover characteristics under a “Configuration B” setup.

Methodology and Instrumentation

The analytical procedure employed a programmed temperature vaporization (PTV) inlet, a four-way flow splitter directing effluent to both MS and FID detectors, and backflush of high boilers. The system used helium carrier gas with pressure programming and operated in simultaneous scan/SIM (FAAST) mode to enhance selectivity and sensitivity. Calibration standards and internal standard (ethylbenzene-d10) were prepared in toluene, and sample oils were diluted 1:2 with the IS solution.

Instrumentation Used

• Gas Chromatograph–Mass Spectrometer: Shimadzu GCMS-QP2020 NX with AOC-20i autosampler
• Inlet: PTV-2030 with Topaz straight inlet liner
• Columns: SH-Rtx-1 (30 m × 0.25 mm ID, df 0.25 µm) and SH-Rtx-5 MS (60 m × 0.32 mm ID, df 0.5 µm)
• Detector splitting: Four-way connector with 1 m × 0.15 mm VSD restrictor to FID
• Detectors: Mass spectrometry (EI ionization, scan/SIM) and flame ionization (FID)

Results and Discussion

Sensitivity testing for styrene (m/z 104) at 1 mg/kg yielded a signal-to-noise ratio of ~1300 (requirement >5). Calibration over five levels showed R² values >0.99 for all 30 analytes and relative standard deviations <3.7%. Analysis of two marine fuel samples detected 13 and 7 target compounds above the highest calibrator, respectively. Phenol concentration differed sixfold between samples, and indene varied by a factor of 42. Carryover testing demonstrated <3% residual carryover for the most abundant analyte after ten injections.

Benefits and Practical Applications of the Method

• High sensitivity and accuracy for regulatory compliance and fuel quality monitoring
• Simultaneous MS/FID detection enhances compound confirmation and quantitation
• Backflush capability reduces column fouling and system downtime
• Reproducible performance supports routine quality assurance in marine fuel analysis

Future Trends and Opportunities

Advancements may include coupling high-resolution mass spectrometry for improved compound identification, accelerated temperature programming or microcolumn technology for faster runtime, and integration of automated data processing with machine learning for real-time fuel quality assessment. Expanding the target list to include emerging contaminants will further strengthen fuel monitoring strategies.

Conclusion

The Shimadzu GCMS-QP2020 NX, configured per ASTM D7845, demonstrated robust performance for quantifying key aromatic and oxygenated pollutants in marine fuel oils. The method’s high sensitivity, linearity and minimal carryover make it a reliable solution for routine laboratory and on-site fuel quality control.