does anyone have any experience with hydrogen as carrier gas in GC-MS?
I tried it and it is 4-7 times less sensetive the helium?
I tried (0.1-0.2)mm, with 0.33thikness,and lenght from (10-25)m, with optimizing the flow and still did not work!
help!!

Unless the compound you analyze is known you cannot get a relevant answer. Hydrogen is known to promote catalytic and possibly homogeneous sample degradation at the injector for pesticides and drugs but not for stable VOCS and petrochemicals. If you wish I can provide references.
Aviv Amirav amirav@tau.ac.il

Walt Jennings had an article in the J&W publication and web site a few years ago dealing with the use of hydrogen as a carrier for GCMS. For some of the older systems, the higher flow rates required to achieve the optimum linear velocity for hydrogen overpressured the ion source, and in some cases the flow was too great for the vacuum system to handle effectively. This was primarily a problem with columns of 0.25 mm id and 25 m length. A column of 25 m in the ids you mention should not have this problem, although a 10 m 0.2 mm column may be marginal.

A diffusion pump will pump hydrogen more efficiently than a turbo will. A system with a relatively small turbo pump may have some difficulty with the flow rates involved with the shorter, wider bore columns.

A final potential problem area is the solvent expansion volume and the liner volume. Head pressures for hydrogen are lower than for helium, thus the solvent expansion volume is larger. If you are using a narrow bore liner, especially if you are doing splitless injections, you may be having flashback and losing analyte in this manner. This is a bigger problem in inlet that don't have a pure splitless mode, such as the HP 5890.

I am assuming you are performing direct injections. For other sample introduction methods there may be other issues, especially for volatiles analysis.

Hope this helps.