Quantification of NSO-HET in fuel samples by GC×GC-ToFMS (Pedro Victor Bomfim Bahia, MDCW 2025)

🎤 Presenter: Pedro Victor Bomfim Bahia (Universidade Federal da Bahia, Salvador, Bahia, Brazil)

💾 PDF presentation

💡 Book in your calendar: 17th Multidimensional Chromatography Workshop (MDCW) 13 - 15. January 2026

Abstract

The polycyclic aromatic sulphur, nitrogen, and oxygen heterocyclic (PASH, PANH and PAOH, respectively) have received increasing attention over the years because they are considered relevant recalcitrant compounds in fuels. However, the determination of NSO-HETs in these matrices (e.g., diesel and gasoline) is a challenge due to the complexity and coelutions problems.

The comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC×GC-ToFMS) has already been successfully employed for qualitative analyses of individual NSO-HET classes, but a simultaneous and quantitative analysis has never been performed. The aim of this study was to, for the first time, apply the GC×GC-ToFMS for simultaneous and quantitative determination of NSO-HET in fuels.

A preliminary liquid chromatography fractionation (LC) was performed to enrich the NSO fraction and remove interferences. After optimization of the chromatographic parameters, the method was validated in terms of matrix-matched calibration. The limits of detection and quantification ranged from 0.34 to 70.34 ng mL-1. Correlation coefficients (R2) ≥0.99 were obtained for all compounds within the linear region (10-1000 ng mL-1). Addition/recovery tests were carried out at three levels (100, 300 and 600 ng mL-1) and the results were within a suitable range (70-120%). The instrumental precision, both intraday and interday, was assessed at two concentration levels (100 and 600 ng mL-1), and relative standard deviation (RSD) was less than 20%.

Finally, the method optimized and validated was applied in fuels, priory and after offline LC fractionation, collected in Salvador, Bahia, Brazil and in Gembloux, Belgium. GC×GC-ToFMS method proved to be precise, accurate, and suitable.

Video transcription

In a significant contribution to environmental chemistry and fuel diagnostics, Pedro Victor Bomfim Bahia presents a pioneering study on the quantification of nitrogen, sulfur, and oxygen-containing heterocycles (NSO-HET) in fuel samples. Utilizing comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-ToFMS), this research introduces a simplified and more efficient method for analyzing these complex compounds both before and after fractionation.

Why NSO-HETs in Fuels Matter

• NSO-HET compounds such as dibenzothiophenes, carbazoles, and furans are resistant to degradation and accumulate in the environment.
• Their presence in fuels (e.g., diesel and gasoline) can lead to engine damage and environmental hazards.
• Conventional methods rely on open-column chromatography, which is labor-intensive, solvent-heavy, and less efficient in separating complex matrices.

Methodology Overview

Pedro’s study innovates by comparing traditional open-column chromatography with HPLC fractionation and applying GC×GC-ToFMS to both fractionated and unfractionated fuel samples.

Key Steps:

• Preparation of 53 analytical standards across sulfur, nitrogen, and oxygen classes.
• Samples included: Marine Diesel, Diesel S500, Diesel S10, Diesel B7, and Euro 95 gasoline.
• Application of HPLC-based fractionation, reducing organic solvent usage.
• Direct and fractionated samples were both analyzed using GC×GC-ToFMS, without requiring separate prep for each class.

Major Findings with Timestamps

• 00:45: Introduction to NSO-HET compounds and their environmental/engine impact.
• 02:30: Explanation of traditional fractionation via open-column chromatography.
• 05:40: Introduction of HPLC-based preparative chromatography as an efficient alternative.
• 08:00: Setup for GC×GC-ToFMS analysis and calibration with matrix-matched standards.
• 13:00: GC×GC results show improved resolution across NSO-HET classes.
• 15:00: Principal Component Analysis (PCA) confirms differentiation between fuel types.
• 17:30: Results highlight 17 sulfur, multiple nitrogen, and 4 oxygen compounds detected, with significant improvements post-fractionation.

Analytical Insights

• GC×GC-ToFMS allowed simultaneous quantification of sulfur, nitrogen, and oxygen heterocycles—previously not achievable without multiple steps.
• Fractionated samples provided better separation, higher recovery, and clearer quantification, especially for sulfur compounds.
• Validation metrics showed strong linearity, accuracy (recovery between 56.6–103%), and low detection limits.

Implications and Future Outlook

• This study sets a new benchmark for fuel quality testing, particularly in identifying trace NSO-HETs efficiently.
• The approach minimizes solvent use, processing time, and analytical overhead while maximizing sensitivity and resolution.
• It is highly scalable and could be adopted by petroleum refineries, environmental labs, and regulatory bodies to ensure cleaner and safer fuel use.

Conclusion

Pedro Victor Bomfim Bahia’s work introduces a robust, validated GC×GC-ToFMS protocol for comprehensive NSO-HET analysis in fuels. By demonstrating clear advantages over traditional methods, this research paves the way for more sustainable, accurate, and scalable fuel diagnostics.

Keywords for Optimization

GC×GC-ToFMS, NSO-HETs, fuel analysis, sulfur compounds in diesel, nitrogen heterocycles, oxygenated aromatics, fractionation, environmental chemistry, fuel standardization, chromatography validation

This text has been automatically transcribed from a video presentation using AI technology. It may contain inaccuracies and is not guaranteed to be 100% correct.