While argon is an excellent choice for H2 sensitivity due to the large difference in thermal conductivity between Ar and H2, it is not a good choice for CO and CO2 since the thermal conductivities are similar. It limits your detection limit. As you already proved to yourself, it is not a separation issue but a detection issue.

Most people running H2, CO and CO2 use a post-column methanizer to detect the CO/CO2 with an FID (you turn them into methane). In the absence of that you may have to go to a complex, dual carrier system whereby you get the H2 using Ar carrier and then switch carriers/columns to He. It is complex and a royal pain in the butt to maintain. FIDs are cheap; you might check into a methanizer/FID setup

Thanks alot Mark. I will look at the possibility of a methanizer

Hi,

CO and CO2 can be easily analysed by GC with a TC detector using He as carrier gas.

Take a 1/4" by 60 cm Molsieve column 60/80 mesh and a sinple temperature program form 50 or 60 °C up to 230°C @ 25 °C/min.

In a single run you can separate Ar+O2, N2, CO, CH4, C2H6 and CO2.

That's a routine GC-method in my Labs for over 30 years.

Of course, the column is "hand made" within 30 min and ready for use after conditioning at 240°C overnight.

Dear you can go for TCD /GC -FID detectors. This will allow to detect low concentrations of carbon monoxide and carbon dioxide.Make sure to use it with catalytic microreactor using a raw catalyst like nickel oxide and look for the temperature maintained.Or you can go for alternative i.e. Polyrac reactor. Hope it will help you dear.