[mir]

How big differences in response (FID/TIC in GC) have you experienced between your product and substrate? I am standing now with a GC chromatogram with 80% yield, but the product is showing up like Himmelbjerget in dennmark (very small) beside the Mount Everest (my substrate) 

[chiralic]

Hi mir:

How do you to know that you have a 80% yield? Are you reaction completed? Is a right column?
Check leaks in your system GC-MS... Did you try use only FID mode?

Congratulations by you analogy between Himmelbjerget ("The Heaven Mountain" or "The Sky Mountain") and the Mount Everest, Very nice!
 
Regards,

Chiralic

[greengiant]

I have often observed huge differences between FID and TIC for reactions that convert a polar/non-polar functional group (like amine protection) on the order of seeing 80% starting material by TIC when in reality the reaction has gone to 90% completion (by FID and TLC).

The most rigorous answer would be to make a standard solution of your starting material and also a standard solution of your product and determine the response factor by injecting a known quantity of each. Alternatively, NMR with an internal standard is easier.

At least your product is not Mount Sunflower next to Denali...

[mir]

How do you to know that you have a 80% yield?

It is tested against an internal standard.

Are you reaction completed?

I am doing the workup tomorrow :-)

Is a right column?
Check leaks in your system GC-MS... Did you try use only FID mode?

Well, the GC/MS is taking a lot in these days (with dirty petroleum and environmental analysis all the time). So the problem might be somewhere in the system (liner, detector etc).

Im going to run a GC with FID only.

But how probably is that the response differences between substrate and product (on TIC or FID), is that huge? We are talking of a small difference in structure, an arene methyl ether against a arene methyl ether with a hydroxy group.

Maybe this molecule I have made could be named Himmelbjerget as a trivial name? 

[chiralic]

Hello mir:

Did you run your "samples" in GC FID mode?  What about your reaction? Was completed?

You wrote:
So the problem might be somewhere in the system (liner, detector etc)...

Did you check it if you some trouble in your system?...

Regards,

Chiralic