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effective carbon numbers for GC-FID
Posted: Wed Jun 14, 2006 4:17 am
by sg
Dear all,
Could anybody here help me to find out the ECNs value for carbon bond with various functional group?
Thank you very much!
Posted: Mon Jun 19, 2006 4:08 pm
by GOM
It isn't a complete answer for you but,
1. The FID will only respond to carbon which can be burned to give CO2
2. So, for example, an oxygen linked to a carbon will effectively "neutralise" that carbon to the FID
3. Therefore, the less carbon atoms in the molecule, the greater the effect as a percentage reduction of signal.
4. So the "substance-specific correction factor" would be for example
Methanol 2.46
Ethanol 1.77
C3 alcohols 1.55
C4 alcohols 1.42
It is a similar story with other oxygenated compounds.
Hope that helps a bit.
Ralph
Posted: Wed Jun 21, 2006 4:16 pm
by MikeD
I would only add that in my experience such factors are not very consistent (for oxygenated compounds anyway) from one FID to another - even the from the same manufacturer and apparently set up the same. If you get less than 10% difference, fine, but don't count on it.
Posted: Fri Jun 23, 2006 12:22 am
by sg
Thank you very much for your information!