Use Hydrogen Carrier to Analyze More Compounds

Importance of the Topic

Global helium shortages have led to significant cost increases and supply limitations for gas chromatography (GC) and GC/mass spectrometry (MS) laboratories. Hydrogen, being renewable and low-cost, emerges as a promising carrier gas alternative. However, hydrogen’s reactive nature can compromise analyses of semivolatile organic compounds (SVOCs), necessitating specialized source designs to maintain analytical performance.

Objectives and Overview of the Document

This document introduces the Agilent HydroInert source, developed to enable robust GC/MS analyses using hydrogen as the carrier gas. It outlines the source’s design principles, evaluates its performance with a model SVOC (nitrobenzene), and highlights operational advantages, including efficiency, sensitivity, and reduced maintenance demands.

Instrumentation Used

The key instrument configuration comprises:

• Agilent HydroInert source (complete assembly for 5977 and 7000 series GC/MS systems)
• Standard extractor source for comparison (3 mm extraction lens)
• Agilent 5977C Inert Plus GC/MSD and 7000E GC/TQ platforms
• J&W HP-5ms Ultra Inert GC column (20 m × 0.18 mm × 0.18 µm)

Main Results and Discussion

Using nitrobenzene as a test analyte, the HydroInert source delivered:

• Reduced hydrogenation by-products: The conventional EI source showed abundant m/z 93 (aniline) due to hydrogenation, whereas the HydroInert source preserved the target m/z 123 fragment with improved ion ratio.
• Enhanced spectral quality: Cleaner mass spectra with lower baseline noise and minimized spectral anomalies when using hydrogen carrier gas.
• Improved chromatographic performance: Faster separations, sharper peaks, and reduced tailing compared to the standard source under hydrogen flow.

Benefits and Practical Applications

Adopting hydrogen with the HydroInert source offers multiple advantages:

• Cost efficiency: Utilizes a lower-cost and renewable carrier gas, reducing operational expenses.
• Laboratory throughput: Shorter run times and optimized separations increase sample throughput.
• Analytical robustness: Sustained sensitivity and reproducibility with minimal source cleaning and downtime.
• Environmental impact: Supports greener analytical workflows by replacing helium.

Future Trends and Opportunities

As hydrogen becomes more prevalent in GC/MS, future developments may include:

• Broader analyte coverage: Method expansion for various SVOCs, volatile organics, and emerging contaminants.
• Source optimization: Further refinement of ionization optics to enhance compatibility with reactive gases.
• Integrated workflows: Automation and software tools designed for hydrogen-based GC/MS operations.

Conclusion

The Agilent HydroInert source effectively addresses the challenges of using hydrogen as a GC/MS carrier gas. By mitigating hydrogenation artifacts and enhancing chromatographic and spectral performance, it enables cost-effective, high-throughput analyses of semivolatile compounds while reducing helium dependency.