Methanol, DME, water and gases
Posted: Wed Aug 19, 2009 8:44 pm
by puff
I use Porapak Q (110°C) 2m column and TCD, Ar as carrier to separate and analyse CO, CO2 and H2 (high level). Currently I must also analyse methanol, water (high level), DME (ppm level) in the same gas sample containing also carbon oxides and H2. Is it possible to do it with Porapak Q, or additional column is necessary? I have also FID in my chromatograph. Isothermal separation is preferential for me. Thanks in advance for any column configuration proposals.
Posted: Thu Aug 20, 2009 2:40 pm
by AICMM
puff,
Don't have specifics on the Q but here is what I think would happen. I would expect water to come out after the CO2, as a big, ugly, tailing peak. Easy enough to test with a room air injection, plenty of water in that. Just make sure you extend your run out quite a bit (like 20-30 minutes.) I would expect that methanol will come out after the water, also probably tailing somewhat. The hard one is the DME. It would come out quite a bit after the methanol. Furthermore, using argon as carrier and TCD, I think it would be difficult to detect ppm levels without swamping the system with the other components.
You might consider setting up a second channel for just the methanol and DME analysis using the FID.
Best regards.