From Helium to Hydrogen: Case Study in the GC-MS Analysis of VOCs and SVOCs

Importance of Topic

The global helium shortage and rising costs threaten the continuity of gas chromatography mass spectrometry methods that depend on helium carrier gas. Transitioning to hydrogen addresses supply constraints and offers potential gains in speed and resolution, particularly for regulated analyses of volatile and semi-volatile organic compounds.

Objectives and Study Overview

This case study optimized EPA Methods 8270 (SVOCs), 524 (VOCs in drinking water) and 525 (VOCs in drinking water) for hydrogen carrier gas. Performance metrics for peak shape, resolution, run time, linearity and sensitivity were compared between helium and hydrogen conditions.

Methodology and Instrumentation

• Sample Preparation: Solvent and standard mixes prepared for SVOCs; purge-and-trap for EPA 524; liquid extraction for EPA 525 with ethyl acetate.
• Gas Chromatography: Replaced 30 m × 0.25 mm column with 20 m × 0.18 mm inner diameter columns to manage backpressure with hydrogen; used split/splitless injector and purge & trap adapter.
• Mass Spectrometry: Installed hydrogen kit in Thermo Scientific ISQ single quadrupole MS; preconditioned by one-hour high-flow hydrogen bake-out with ion source at 350 °C.
• Data Analysis: Employed Thermo Scientific Xcalibur, Target or TraceFinder software for direct target processing and quantitative evaluation.

Main Results and Discussion

Hydrogen bake-out effectively desorbed contaminants and reduced low-mass background ions (m/z 18–41). Linearity studies over method ranges yielded R2 > 0.99 with %RSD meeting EPA criteria. Instrument detection limits with hydrogen (0.15 ppm for EPA 8270; 0.074 ppb for EPA 524) were comparable to helium. Hydrogen enabled faster separations, narrower peaks and improved resolution of critical PAH pairs, reducing total run time by approximately 20 %.

Benefits and Practical Applications

• Reduces dependency on scarce helium — lower operational costs and supply risks.
• Increases sample throughput via shorter chromatographic runs.
• Ensures regulatory compliance for complex environmental analyses.
• Enhances maintenance intervals through in-situ source cleaning by hydrogen species.

Future Trends and Potential Uses

Integrating on-site hydrogen generators will streamline carrier gas supply. Broader adoption across environmental, food safety and industrial laboratories is expected. Advances in high-resolution MS and automated data platforms may further leverage hydrogen’s chromatographic advantages.

Conclusion

This study demonstrates that GC-MS methods for VOC and SVOC analysis can be successfully migrated from helium to hydrogen carrier gas with minimal method redevelopment. Hydrogen offers comparable performance, operational benefits and strategic resilience against helium scarcity.

Used Instrumentation

• Thermo Scientific TRACE 1310 GC with Instant Connect split/splitless injector.
• Thermo Scientific ISQ Series single quadrupole MS equipped with hydrogen kit.
• TraceGOLD TG-5MS and TG-VMS capillary columns (20 m × 0.18 mm × 0.36 µm or 1.0 µm film thickness).