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Hydrogen versus helium as carrier gas with opium alkaloids

Posted: Mon Mar 20, 2017 7:26 pm
by osp001
Client is seeking exemption from DEA/ICE regulation on natural products imported for decorative purposes. These are to be run on GC/FID because the client doesn't require high sensitivity.

I have attempted to replicate two methods found for running underivatized opium alkaloids on GC; still can't get good peaks with the standards. However, the methods I have found all use helium as carrier gas, while we run hydrogen. Is there any reason these alkaloids wouldn't show up using GC/FID using hydrogen as carrier gas? The other parameters (pressure, linear velocity, timing, etc.) have been adjusted for hydrogen from helium.

Example Restek chromatogram: http://www.restek.com/images/cgram/gc_ph00235.pdf

Re: Hydrogen versus helium as carrier gas with opium alkaloids

Posted: Mon Mar 20, 2017 7:56 pm
by tkubowicz
Hello

In my opinion it'd be better if you paste problematic chromatogram with full method description (parameters) rather than sample chromatogram from Restek website.

Regards

Tomasz Kubowicz

Re: Hydrogen versus helium as carrier gas with opium alkaloids

Posted: Mon Mar 20, 2017 9:49 pm
by Peter Apps
To get a chromatogram that good you would need a brand new column and a base-deactivated inlet liner. What you use as carrier gas will not make a difference.

Peter