Chromatography Forum

Hi all I have a question.

I have a 5890-FID. It uses 40 ml/min of He as makeup. Can I use He as a carrier and N2 as makeup to conserve He and save money.

Or I suppose I can simply turn off the makeup when not running samples.

Hi all I have a question.

I have a 5890-FID. It uses 40 ml/min of He as makeup. Can I use He as a carrier and N2 as makeup to conserve He and save money.

Or I suppose I can simply turn off the makeup when not running samples.

In my opinion both solutions are possible.

N2 as makeup is preffered, and when not running samples, the flow may be reduced as well.

With He as a carrier you can use N2 as a make up and turn off the make up flow when not in use. If you'd like to do away with the He completely, you can use H as a carrier and N2 as a make up and that's actually the preferred gas recommendation for an FID with a cap column.

Yep I am pretty sure we will eventually be doing way with He for both the GC/MS and GC. The only issue us one we use a validated method for 3-mcpd and I am not sure about the Gerstell (ODP) GC-O sniffer port if it is ok to have hydrogen as a carrier.

All the comments are good ones.

The only concern I might have is the type of MS you are preforming. While having no experience with the problem I have understood that some have seen changes in the spectrum of analytes when using hydrogen carrier in some MS systems.

I would contact your MS vendor for advice.

best wishes,

Rod

Nitrogen as make up with helium as carrier, or as already mentioned hydrogen as carrier is the best solution. Turn off all the gasses to the FID when not running samples - but leave the FID heater on.

I have done GC-sniffing with hydrogen as carrier with no problems at all - using home made sniffer ports which might be different to the Gerstel.

Peter

FYI, there's a webinar coming up soon on converting your GC/MS from helium to hydrogen. It's listed under Announcements and the link to sign up is http://www.cen-online.org/media/webinar ... 00912.html.

Yep already registered.

Another complication is I use the Agilent Quickswap and the reference manual says don't use H2 as the purge gas even though they give the values to be able to do it in the manual. Perhaps a bit of finger waving.