Basic alumina also works, and also gets rid of traces of water. I like to use
a small plug of cotton wool and push that into place with the end of a second
Pasteur pipette. Dusty samples can be filtered through a plug of Celite.
Thomas
________________________________
> From: main_at_ammrl.groups.io on behalf of Karel Klika via groups.io
> Sent: Friday, April 26, 2024 6:20:50 PM
> To: main_at_ammrl.groups.io <main_at_ammrl.groups.io>
> Subject: Re: [AMMRL] Silver Strips in CDCl3?
Dear all,
A faster way to deal with traces of acid is plug a Pasteur pipette with some
tissue (can be packed fairly tight for CDCl3) and then add some Na2CO3
(0.5-1 cm is usually sufficient) and then allow the CDCl3 solution to percolate
through directly into the NMR tube. The residual amount of non-absorbed CDCl3
solution retained in the Na2CO3 bed and tissue can be pushed through by
applying some gentle pressure with a pipette bulb (hence it helps to have
the tissue packed in nice and tight to retain the Na2CO3), or simply use
more CDCl3.
Regards,
Karel
________________________________________
> From: main_at_ammrl.groups.io on behalf of Platz Hirsch
> Sent: 24 April 2024 10:44:22
> To: main_at_ammrl.groups.io
> Subject: Re: [AMMRL] Silver Strips in CDCl3?
Hello,
that’s no direct answer concerning your question.
If you have really sensitive samples, the best way is to add a tiny amount
silver oxide directly into the NMR tube.
You might be interested to check out the effect.
Take CDCl3 as a solvent and add a drop of methanol. You should see two singlets,
one for the methyl, one for
The OH group. Now add a few micrograms of silver oxide. You have to shake it
a rather long time. Long time means
At least one hour. An ultrasonic bath should do the job.
Insert the sample immediately into the spectrometer to keep light away and
wait a few minutes to allow the silver
Oxide to move to the bottom of the tube.
And then measure again. You should see the expected doublet for the
Methyl and a quartet for the OH group.
Greetings
Rainer
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Received on Fri Apr 26 2024 - 18:13:03 MST