Chromatography Forum

Hello all

I have a GC Agilent 6850 with TCD, I've tried to separate CO, CO2, O2, and N2 without any good results (I know it isn't easy). I tried with a i) HP-PLOT Molesieve and ii) HP-PLOT Q. I use He as a gas carrier.

I read in other topic that Carboxen 1004 column is good for this analysis, can I use this column in my GC?... Any other suggestion?


Thanks

I would suggest that a 4.5 meter Carboxen 1000 60/80 2mm ID column would perform the O2, N2, CO, and CO2 separation, depending upon the sample size. (H2 and methane is also separated)

But isn't your 6850 a capillary column ONLY GC? Installing a packed column into a dedicated capillary instrument might be troublesome, but it is possible. Bypassing the pneumatics is the easier path, but will you be using a µTCD?

You might have to install an injection site outside the GC oven but that is not a problem.

One PLOT column that will perform this analysis would be Molecular Sieve 13X. The Molecular Sieve 5A will NOT separate these four analytes, as CO2 will be trapped in the pores of the 5A.

To use a Carboxen PLOT column is possible but sample capacity is limited and the O2/N2 separation could be affected.

If you use a porous polymer column (packed or PLOT) it will require subambient temperatures.

best wishes,

Rod

thank you Rod.... I'll discuss your suggestions with my advisor

A ten port sampling and backflush trap valve or two 6 port valves would allow you to use a porous polymer and a MS5a column and perform this analysis.

There are third party vendors that will supply you with the hardware and the technical details.

best wishes,

Rod

yeah!!! I just found that option, with the system scheme .... It's a shame that I don't have the last word... and money

Thanks again