Yes. What type od column you have? A PLOT column is a must.

Regards

G

Surely yes, but He is much more expensive that Ar

Please note, He and Hydrogen have almost the same retention time in GC So, its better to change the carrier gas, either use N2 or Ar. He carrier gas might give ambiguity in results.

Yes, but response will be low as both Hydrogen (0.182 W/mK) and Helium (0.151 W/mK) have similar thermal conductivities. Better to use Ar (thermal conductivity = 0.018 W/mK), cheaper than He and good separation.

Yes, if you have a PLOT column.. but I would also recommend switching to argon. Keeping the GC-TCD running for long periods of time with He can be expensive, and continuous flow (gas saver mode) is preffered to avoid water getting into the system.

Just keep in mind..

To preserve the resolutions of all peak pairs when switching from helium as a carrier gas to argon in the same column, do the following: 1. Before switching, measure the initial flow rate and the initial hold-up time in the analysis with helium (initial means at initial temperature, 50 C in your case) 2. Choose the initial flow rate of argon 3.85 time lower than the initial flow rate of helium 3. Measure the initial hold-up time in the analysis with argon 4. Calculate the ratio (G) of the measured hold-up times with argon and with helium 5. Rescale the temperature program with argon in proportion with G. Example. Suppose that G=3 (the hold-up time with argon is 3 times longer than with helium). In this case, instead of the temperature program with helium (50 C (10 mins) at 10 C/min to 120 (5 mins)), use this one: 50 C (30 mins) at 3.33 C/min to 120 (15 mins). [taken from https://www.chromforum.org/viewtopic.php?t=27090]

Good luck!

-S

Hi Grzegorz Boczkaj ,

Yes it is a HP-PLOT Q column .

Thank you .

Regards,

A

Hi Yurii V Geletii ,

I dont have Argon , If I can do that with Helium that will be okay , can you tell me how to do it ?

Thank you for the response .

Regards,

A

Hi Stephanie Colon-Santos and thank your for the response .

in my case i can not use Ar because the instrument is set up for some other purposes also . I was looking for using the same set up with He , if you know how to do it with He , it will great if you can tell me how .

Regards,

A

Hi, Saurav Sorcar and Rayees Ahmad Rather ,

Thank you for your response . I will try to find a nother GC with Ar or N2 . in this instrument I cant change the carrier gas as it is being using for many other purposes here , I was wondering if its possible to do it with helium.

regards,

A

Hi I have the same problem. I have HP PLOT Q column and helium as a carrier gas and cannot change it with argon. Anyone can help me if it is possible and how? I have injected my samples and did not get any peaks.

Connect the gas source of Ar in the place of carrier gas and TCD reference (and makeup if you have this option). Define it in the program. Depending on the compounds maybe you need to change the polarity (?). Probly also the bridge current should be changed.

Regards

G