Robust, Sensitive, and Reliable ACCUTRACETM Plus Fuel Marker Analysis by Two-Dimensional GC/MS Using Hydrogen as the Carrier Gas

Význam tématu

Fuel marking plays a critical role in protecting government revenues by deterring the illicit trade of lower-tax or tax-exempt fuels. National and regional authorities rely on chemical markers to authenticate the origin and tax status of fuels. At the same time, analytical laboratories face rising helium costs and supply constraints, driving the need for robust methods that employ alternative carrier gases without losing chromatographic performance.

Cíle a přehled studie

This study demonstrates the quantitative analysis of ACCUTRACE™ Plus fuel marker (butoxybenzene) in diesel using two-dimensional gas chromatography coupled with mass spectrometry (2D GC/MS). The method employs hydrogen as the carrier gas and a capillary flow technology (CFT) Deans switch to achieve sensitive detection at mg/L and sub-mg/L levels, meeting regulatory marking limits and laboratory efficiency requirements.

Použitá metodika a instrumentace

The analytical setup comprises an Agilent 8890 GC system with split/splitless inlet, flame ionization detector (FID), and a CFT Deans switch, coupled to an Agilent 5977B GC/MSD operated in selected ion monitoring (SIM) mode. Hydrogen is used as the carrier gas to replace helium. Key components include:

• Primary column: Agilent J&W DB-17ht, 15 m × 250 µm, 0.15 µm
• Secondary column: Agilent J&W DB-WAXetr, 30 m × 250 µm, 0.5 µm
• Deans switch for heart-cutting and concurrent backflush to protect the MS source
• MSD extractor source monitoring m/z 94 and 150 with 100 ms dwell time

The method uses direct injection of diesel fuel spiked with butoxybenzene standards in m-xylene, with a six-point calibration from 0.05 to 10 mg/L.

Hlavní výsledky a diskuse

The method exhibits excellent linearity (R2 = 0.99998) across the calibration range, with accuracy better than 10% at all levels. At the lowest standard (0.05 mg/L), the S/N ratio exceeds 28:1, demonstrating sufficient sensitivity for trace analysis. Reproducibility tests of 20 injections of a 0.14 mg/L spike in diesel yielded an RSD of 1.07%. The Deans switch heart-cut window was optimized to 0.1 min, minimizing matrix load on the MS and enabling run times under 15 min while maintaining column integrity.

Přínosy a praktické využití metody

The proposed approach offers several advantages:

• Eliminates dependence on helium by using hydrogen without sacrificing chromatographic resolution
• Provides robust protection of the MS source via heart-cutting and concurrent backflush
• Delivers rapid analysis suitable for high-throughput quality control
• Meets regulatory requirements for fuel marker quantification at mg/L and sub-mg/L levels

Budoucí trendy a možnosti využití

Future developments may include integration of automated sample preparation with on-line GC/MS systems, adoption of alternative carrier gases such as nitrogen for certain applications, and further miniaturization of Deans switch assemblies. Advances in 2D GC software and hardware could enable even faster analyses with enhanced data processing for real-time compliance monitoring.

Závěr

This work validates a hydrogen-carrier 2D GC/MS method using a CFT Deans switch for reliable, sensitive, and efficient quantification of butoxybenzene fuel marker in diesel. The approach addresses helium shortages, reduces analysis time, protects MS instrumentation, and meets stringent regulatory standards.

Reference

1. Sandy C. Fuel Marker Analysis in Diesel Fuel Using 2D-GC/MS, Agilent Technologies solution note, publication number 5991-6219EN, 2015.
2. Implementing Decision (EU) 2022/197 of 17 January 2022, Establishing a Common Fiscal Marker for Gas Oils and Kerosene, Official Journal of the European Union L 31/52.