In gas chromatography, a carrier gas is usually an inert gas such as helium or an unreactive gas such as nitrogen. If analysis of helium or hydrogen is required on TCD channel, the carrier gas must be argon. We have been successfully used argon as a carrier gas for hydrogen detection on our Micro GC device.
We used Helium as a carrier gas and it worked for H2 at high concentrations, above 2000 ppm, but lower then that the detection wasn't good. So I agree with Erkan, you should select Argon.