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- Posts: 35
- Joined: Mon Aug 19, 2013 4:34 pm
I am looking to analyze CO/H2/CH4/C2H4 (in decreasing order of importance and concentration) in a CO2 stream using a 6890N with a sampling valve. Now, there are two things in which I am a bit clueless and I would greatly appreciate any tips and hints: 1) deciding whether the column/detector/carrier combo would work, and 2) calibration.
Regarding (1), I am planning to use helium as carrier with a TCD. I am aware that analyzing hydrogen in He with a TCD is far from optimal, but can it be done? What should one look out for? Would it be better to use a different carrier gas altogether? (however, I am more interested in accurately determining CO than H2).
There is an FID installed in the GC which I could use (either in series after the TCD, or use a splitter from the column). Would this be a good idea, or is it overkill?
As for the column, I am planning on using a Carboxen-1010 capillary column (http://bit.ly/18ZfdIg), which seems suitable. It is preferable to go with the 0.32 mm column instead of 0.50 mm, correct?
As for the calibration, I have been looking into using gas mixtures of each component (e.g. CO in He at different concentrations) to make a calibration curve for each. However, buying (for example) 3 cylinders of each component seems a bit... wasteful (and costly!). Is there a better way to go about this?
Thanks for your help!
p.s. it might be useful to add that a likely "lower boundary" for the concentration of the analytes (in molar terms) in the carbon dioxide flow would be:
- Carbon monoxide: 1200 ppm
- Hydrogen: 60 ppm
- Methane: 35 ppm
- Ethane: 35 ppm