PERMANENT GASES DETECTION BY MS

[cristiancerda]

Hello everybody.
I have a Shimadzu QP2010 plus (GC/MS) and need detect permanent gases from biomass pyrolysis.(H2,CH4, CO, CO2, C2H2, C2H4). I pretend to use a capillary column like RT MSieve 5A, QPLOT or similar.
The pyrolysis gas is generated with N2 from a TGA or from heated reactor. To date analyze tars and non-condesables using a RTX 5MS capillary column with satisfactory resolution, but i think so permanent gases pass quickly together N2 through column.
N2 generates a big signal that saturate MS, therefore i turn off detector for cutting solvent (N2 in this case). This don't permit detect these gases . I tried SIM mode for several M/Z corresponding to these gases (2, 15, 28, 44, ) but doesn't work.

The gas from reaction is injected to GC by a Valco 6-port valve mounted over SPL injector and housed in a heating box for this purpose. Anybody have tried detect permanent gases by MS? since sadly i dont have TCD in my configuration.

Please post ideas,
Best regards,

Cristián

[chromatographer1]

I believe you have discovered that having the most expensive detector is not always having the correct detector.

An ionization detector (not a FID) like a HID or pHID: from Gow-Mac, Valco, AIC

or even a lowly TCD would be a better choice than a MS.

Good luck,

Rod

[AICMM]

cristiancerda,

Look in the GC-MS section of this site and you will find a good deal of information on why MS is going to be a very challenging detector for fixed gases. Sorry to be such a downer but this much more easily done with a GC detector rather than MS.

Best regards,

AICMM