Change of carrier gas

[aniket1706]

Dear All,
This particular question is being raised with respect to Indian Pharmacopoeia. I did not find any suggestions on whether it is allowed to change the carrier gas (I want to use helium instead of nitrogen which is specified in pharmacopoeia). I am analyzing ethanol (95%) and would like to improve resolution in system suitability between methanol and acetaldehyde (NLT 1.5). With nitrogen, I am getting resolution of 1.0 with nitrogen.
If I change the gas to helium, do I need to perform method validation or can proceed with method verification?
Please help and suggest.

Best regards,

Aniket

[DR]

Yes, you will need to demonstrate equivalency after figuring out your new flow rates etc. This is a significant undertaking - make sure you'd rather do the work than just replace a column or repack (if it's a packed column method).

That said, if you're going to switch, switch to Hydrogen! You'll save $$$ and possibly improve your resolution.