This is the latest version of the guide to converting an Agilent EI GCMS system from using Helium carrier gas to using Hydrogen carrier gas.
These 36 pages also include information about the Agilent HydroInert Ion Source that is designed to be used exclusively with Hydrogen carrier.
In general, helium is always a better choice for GC/MS analysis. If helium is available at a reasonable cost, it is clearly preferred. However, if it is not an option, hydrogen can be considered. The purpose of this document is to help users of Agilent EI GC/MS systems determine if hydrogen can be used as a carrier gas for their analyses and what considerations and procedures are necessary to make the transition successful.
Regardless of the method to be adapted, there will be at least some changes required. Therefore, it is necessary to allot time for the necessary updates to SOPs and method validation. It is important to recognize the differences between using hydrogen and helium carrier gas. Time should be allotted for adapting the methods, optimization, and resolving potential problems. There are several topics to consider when converting from helium to hydrogen carrier for EI GC/MS.
Areas that will need attention are discussed in the following sections and include:
- Hydrogen safety
- Source of hydrogen
- Plumbing for hydrogen
- GC/MSD and GC/TQ hardware changes
- Choosing new chromatographic conditions
- Initial startup with hydrogen
- Potential reduction in signal-to-noise ratio (2 to 5 times or more) due to higher noise
- Changes in spectra and abundance ratios for some compounds
- Activity and reactivity with some analytes