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aldehydes by GC
Posted: Wed Aug 02, 2006 8:37 am
by WK
Hi All,
Has anyone tried stabilising a low MW (C8/C10) aldehyde mix?
Mine is in hexane and the response tails off quickly - within a week.
Thanks in advance.
WK
mix
Posted: Wed Aug 02, 2006 2:03 pm
by chromatographer1
Chemistry happens. Aldehydes react even with themselves, also in the presence of water and oxygen, like everywhere on earth.
Keep your mix in a freezer and use in small portions.
Allow to come to ambient temperature slowly.
best wishes,
Rod
Posted: Wed Aug 02, 2006 8:38 pm
by Radish
They behave even worse in methanol. I have had some success with acetonitrile.
aldehyde mix
Posted: Wed Aug 02, 2006 8:40 pm
by khirth
I have not encountered reduced response of a mix of aromatic aldehydes due to degradation upon storage. However, my mix was in high purity acetone instead of hexane. (Don't know if that makes a big difference.)
By "tails off quickly" I presume you mean that the response decreases, not that the peak shapes tail.
In my aldehyde mix I did observe significant tailing. It was particularly noticeable on the peaks of very low concentrations. (I wasn't seeing tailing in aldehydes standards because the concentration of the standards was much higher. Thus the tailing was a much smaller perturbation on the lineshape.) Changing from 5% phenyl to a WAX column improved peak shape significantly. And, the acetone solutions are very stable.