Which Gas is Better?

Comparing Hydrogen and Helium for GC

With fluctuations in the global helium supply market, many gas calibration users are looking at other options. Hydrogen is a promising alternative carrier gas for multiple reasons. While helium can only be obtained by purchasing canisters from a supplier, hydrogen can be easily produced in virtually unlimited supply using a gas generator.

Hydrogen offers multiple advantages for GC applications, comparing favorably to helium. Ultimately the question "which is better" can only be answered by each lab based on your specific application needs.

But when produced by an on-site gas generator, hydrogen is actually safer than storing high-pressure cylinders of helium or other carrier gasses on site. Using a hydrogen generator often provides greater convenience, availability, purity, and faster analysis times, at a lower cost. Compare for yourself in the chart below:

Comparing Helium and Hydrogen Characteristics and Suitability for GC Applications

Helium Hydrogen
Atomic number 2, noble gas 1, nonmetal
Reactivity Inert Reactive
Toxicity Non-toxic Non-toxic
Properties Lowest boiling point: 268.9°C
Liquid at ultra-cool temperature		 Low atomic mass: 1.007825 g.mol-1
Low boiling point (l/c) –252.8°C
Molecule size Van Der Waals radius: 0.118 nm Van Der Waals radius: 0.12 nm
Thermal conductivity (W/m K) 0.146 0.161
Viscosity (μPa·s) 18.6 8.4
Density (kg/m³) 0.169 0.0852
Reactivity Very inert, will not react with analytes Reactive under some circumstances
Flammability Non-flammable Can form explosive mixture with air at >4% concentration
Sustainable Non-replenishable resource Easily generated from deionized water
Separation time Time-efficient separations Most time-efficient separations
Cost Increasingly costly Affordable especially via in-house gas generator
Supply Mode High-pressure gas cylinders High-pressure gas cylinders or gas generators