Hydrogen Detection with a TCD using Mixed Carrier Gas on the Agilent Micro GC

This application note highlights percentage level analysis of hydrogen on an Agilent Micro GC using a mixed carrier gas. Hydrogen is typically analyzed with argon carrier gas on a thermal conductivity detector. Argon however, will result in a decreased sensitivity for the other permanent gases. Helium carrier gas is, in most cases, also not a suitable alternative. Mixtures of helium and hydrogen give nonlinear conductivity response and signal inversion with strange s-shape peaks when hydrogen concentration increases. The use of a mixture of 8.5% hydrogen in helium as the GC’s carrier gas results in a hydrogen concentration in the detector above the point of inversion. The resulting negative peak for hydrogen can easily be integrated. This enables the detection of a broad range of hydrogen on the same channel as the other permanent gases, while maintaining the sensitivity for these compounds.