Derivatization/Silylation

[kostas]

Hello everyone!

I have recently started using a new Shimadzu GC-2014 gas chromatograph, which is a replacement for an old HP 5890. However, the column is still the old one from the HP 5890. I am doing gas injections with a sampling valve. The reactant of my reaction is propanol and the main product is propanal with smaller quantities of aldol condensation products and propane.

We have had big problems with tailing of the oxygenate peaks, which greatly reduces the sensitivity for the later peaks. My PI suggested that this is due to the column (HP-1) being activated by silanol groups on the stationary phase and suggested that I use some silylation reagent to cap these groups. Does anyone have any idea how to do this? There is trimethylchlorosilane in the lab, which apparently can titrate the silanol groups and form nonpolar groups.

Many thanks,

Kostas

[Jumpshooter]

Try out your idea of using the named reagent to titrate "off" the activated silanols that purportedly are on your HP 1 phase column. Then, run your sample and see if you have tailed oxygenate peaks.
Pls report back to us of your findings.

Thanks.

[kostas]

That is exactly the problem; I do not have any ideas as to the procedure I should use. I am a bit apprehensive, because I do not want to damage the FID or any other parts of the system, as HCl gas will come out.

[krickos]

Why not first consider changing to a more inert column (different brand) or increasing filmthikness?