We have Heysep (to separate CO2) and Molsieve 13X (to separate other gases) columns to separate these gases.
Conc. levels are less than 5% for all gases except Ar.
Can anyone please suggest me the best carrier gas to spearate these?
Will helium interfere hydrogen conc. if He is used as carrier?
As nearly 80% is argon, Is argon good choice as carrier gas?
Is there any of these gases poison to these columns?
Helium and hydrogen are going to be difficult to separate. You'll need to run at a low flow rate and at near ambient temperatures. If you can easily run sub-ambient, that would be a good thing.
If the CO2 is introduced onto the Molesieve column it can take a long time to elute. If you can use the Hayesep to separate the CO2 from the rest of the sample then have it by-pass the Molesieve, that would also be a good thing.
Running a helium carrier would, obviously, prevent you from quantifying the helium concentration. The 80% argon peak will be so large that it will be hard to quantify it with good repeatability, and it may interfere with other peaks.
Using a carrier that is the same as your balance (a.k.a. matrix) gas is usually the easiest way to go. In this case that's argon. Your sensitivity will be less than with a helium carrier, but if you're looking for components with percent-level concentrations, sensitivity shouldn't be an issue.
Summary:
Argon carrier. Start with low flow and temperature to resolve the helium and hydrogen. Steeply ramp up the temperature and, if possible, the flow, after the helium and hydrogen come off to get off the CO2 in a reasonable time frame.
By chance are you running this on an SRI GC?