How to convert helium to hydrogen as a carrier gas in gas chromatography

Significance of the Topic

Hydrogen generated on site as a carrier gas for gas chromatography addresses global helium shortages while improving laboratory safety, reducing operational costs, and increasing workflow convenience. This approach supports uninterrupted analytical operations and aligns with sustainable laboratory practices.

Objectives and Study Overview

This guide presents a structured procedure for converting gas chromatographs from helium to hydrogen carrier gas using in-house gas generators. It outlines key preparatory steps, system modifications, flow optimizations, and the transition from cylinder-supplied gases to fully generator-based configurations.

Methodology and Instrumentation

Conversion follows five major steps:

• Review and record existing run parameters including dead volume, linear gas rate, septum vent, make-up and detector gas flows, and temperature programs
• Perform routine GC maintenance: replace purifiers, septa, injection port liners, seals, and clean detector components
• Install new hydrogen and nitrogen lines, add gas purifiers to achieve >99.9999 purity, and integrate tees for carrier gas switching
• Establish and stabilize flows: set column, split vent, detector, make-up, and air flows; calculate and adjust linear gas rate; perform initial sample runs and calibration
• Replace gas cylinders with on-site hydrogen, zero air, and zero nitrogen generators, minimize line lengths, and configure modular gas station layouts

Pouzitá instrumentace

Primary equipment involved includes:

• Gas chromatograph with appropriate detector modules (FID, ECD, etc )
• Parker domnick hunter H-MD series PEM hydrogen generators delivering up to 1100 ml/min of 99.99995 purity hydrogen
• Parker domnick hunter UHP-ZA zero air generators for combustion detectors providing organic-free air at up to 30 L/min
• Parker domnick hunter UHPZN2 zero nitrogen generators for makeup or carrier gas supplying up to 3 L/min of 99.9995 purity nitrogen
• Copper or stainless steel tubing and high-performance purifiers for hydrocarbon, oxygen, and moisture removal

Main Results and Discussion

Experimental comparisons demonstrate equivalence or improved separation performance when operating at typical linear gas rates of 25 to 50 cm/sec with hydrogen versus helium. Chromatograms obtained post-conversion showed consistent retention times and resolution. Overnight purging and extended warm-up periods enhanced system stability. Cost analyses indicate dramatic savings: annual running costs drop from tens of thousands of euros for cylinders to under 700 euros per year with on-site generation.

Benefits and Practical Applications

• Safety improvements by eliminating high-pressure cylinders and limiting stored hydrogen volume
• Cost reduction through low maintenance budgets and avoidance of cylinder rental, shipping, and handling fees
• Convenience of 24/7 automated gas supply with minimal operator intervention
• High analytical performance across GC and GC/MS applications including trace analysis with combustion detectors

Future Trends and Possibilities

Advances in generator networking and remote monitoring will enable centralized control of multiple gas sources, further reducing downtime. Integration with laboratory information management systems can automate maintenance scheduling and purity monitoring. Emerging membrane and catalyst technologies may yield even higher purities and lower energy consumption. Wider adoption of alternative carrier gases will drive innovation in column design and detector compatibility.

Conclusion

Converting from helium to hydrogen carrier gas via in-house generation is a viable strategy for modern analytical laboratories. It offers significant safety, economic, and performance benefits while supporting sustainable resource use. A systematic implementation following maintenance, installation, flow optimization, and generator integration ensures a seamless transition with minimal impact on existing methods.

References

No literature references were provided in the original text.