Hydrogen Impurity Analysis Using the Agilent 990 Micro GC

Significance of the Topic

Hydrogen is emerging as a clean energy carrier for fuel cell vehicles, but trace impurities can impair fuel cell performance and longevity. Monitoring ppm-level contaminants such as noble gases, nitrogen, oxygen, carbon monoxide, methane and carbon dioxide is essential to ensure the quality and reliability of hydrogen used in fuel cells.

Objectives and Overview of the Study

This study evaluates the Agilent 990 Micro GC’s capability to rapidly and sensitively quantify hydrogen impurities at concentrations from 2 to 10,000 ppm. Two standard gas mixtures covering a range of impurities were analyzed to assess separation efficiency, repeatability, and total analysis time.

Methodology

The analysis employed high-purity hydrogen (>99.9995%) as carrier gas, eliminating matrix interferences and enhancing detector response. Two capillary channels were used: a 20 m CP-Molesieve 5Å column for noble gases and permanent gases, and a 10 m CP-PoraPLOT U column for hydrocarbons and carbon dioxide. Operating conditions included column temperatures of 75 °C and 50 °C, injector temperature of 50 °C, pressures of 230 kPa and 120 kPa, and injection times of 40 ms and 50 ms for the two channels.

Used Instrumentation

• Agilent 990 Micro GC with low-dead-volume micro thermal conductivity detector (µ-TCD)
• 20 m CP-Molesieve 5Å column
• 10 m CP-PoraPLOT U column

Main Results and Discussion

Chromatograms demonstrated baseline resolution of helium and neon, and clear separation of argon, oxygen, nitrogen, carbon monoxide, methane and carbon dioxide. The resolution between argon and oxygen reached 1.13. Ten-run repeatability tests yielded retention time RSDs below 0.1% and peak area RSDs under 5% for most gases, except oxygen at 5.28%. The total analysis time was under 150 s, enabling rapid quality assessments.

Benefits and Practical Applications

• Fast, reliable detection of multiple impurities in a single, portable system
• High sensitivity and repeatability for ppm-level analysis
• On-site hydrogen quality control for fuel cell vehicle refueling stations

Future Trends and Potential Applications

Advances may include integration into automated online monitoring systems, extension to additional impurity classes, coupling with complementary detectors, and deployment in decentralized hydrogen production and distribution networks to support real-time quality assurance.

Conclusion

The Agilent 990 Micro GC provides fast, accurate, and repeatable analysis of hydrogen impurities at ppm levels, with separations completed in under 2.5 minutes. Its portability and high performance make it well suited for field and laboratory deployment in hydrogen fuel cell applications.

References

• Van Loon R. Permanent Gas Analysis—Separation of Helium, Neon and Hydrogen on a MolSieve 5Å column using the Agilent 490 Micro GC. Agilent Technologies application note, 5990-8527EN, 2011.
• Bajja M. Permanent Gas Analysis—Separation of Argon and Oxygen on a MolSieve 5Å column using the Agilent 490 Micro GC. Agilent Technologies application note, 5990-8700EN, 2011.
• Van Loon R. Mud Logging—Rapid Analyses of Well Gases with an Agilent Micro GC. Agilent Technologies application note, 5991-2699EN, 2013.