Date: Tue, 22 Aug 2023 14:07:18 -0400
Hello Weixing,
If radiation damping is the problem, you might be able to get a spectrum
without its effect by using the shortest pulse width with lowest level of
RF power possible, i.e. a very very small flip angle. This will let you
use the calibration sample you already have (80% ethylene glycol) and the
well established NMR temperature measurement parameters.
Regards,
Donghui
On Tue, Aug 22, 2023 at 1:03 PM Zhang, Weixing via groups.io <Weixing.Zhang stjude.org_at_groups.io> wrote:
> Dear All,
>
>
>
> Thanks to everyone who has read and replied to my email.
>
> We want to use a CryoProbe to run experiments at different temperatures up
> to 90 oC (363 K).
>
> Many people think that radiation damping of 80% ethylene glycol is the
> problem.
>
> Massively detuning the cryoprobe or using deuterated ethylene glycol
> should give more accurate results.
>
>
>
> Clemens told me that the Bruker part number of 99% ethylene glycol-d6 is
> Z10629.
>
> Z10629 is currently under development in Germany and it would be about a
> month for it to be completed.
>
>
>
> The Bruker AU program calctemp has these options.
>
>
>
> I am curious where Bruker got the equations from, and I would greatly
> appreciate any information.
>
>
>
> With warm regards,
>
>
>
> Weixing Zhang (Walter)
> Research Operation Manager
> Biomolecular NMR Spectroscopy Center
> St. Jude Children’s Research Hospital
> Memphis, TN 38105
> USA
>
>
>
>
>
> *From:* main_at_ammrl.groups.io <main_at_ammrl.groups.io> *On Behalf Of *Clemens
> Anklin via groups.io
> *Sent:* Friday, August 18, 2023 2:26 PM
> *To:* main_at_ammrl.groups.io
> *Subject:* Re: [AMMRL] 99.8% MeOD vs 80% Ethylene Glycol
>
> Hi Weixing
>
> if you do this on a cryoprobe this will be the expected result. 80% Glycol
> gives a massive amount of radiation damping. This leads to different
> readings as shown by Stefan Berger in https://doi.org/10.1002/mrc.1941
>
> You can try to run a more accurate measurement by massively detuning the
> probe.
>
> With best regards
>
> Clemens
>
> On 8/18/2023 3:09 PM, Walter Zhang wrote:
>
> Dear All,
>
> I need to use 80% Ethylene Glycol for high temperature calibration.
>
> Before I do the calibration, I compared it with 99.8% MeOD at 303 K.
>
> When I set temperature to 303 K,
> 99.8% MeOD gives 303.03 K while 80% Ethylene Glycol gives 300.57 K
>
> The difference between the two calibration samples is 2.46 K.
>
> Is this normal?
>
> Your comments are appreciated!
>
>
>
> Best regards,
>
> Weixing Zhang
> St. Jude Children’s Research Hospital
> Memphis, TN 38105
> USA
>
>
>
>
> ------------------------------
>
>
>
> -- ======================================================================
> Clemens Anklin Ph.D. Vice President Bruker BioSpin NMR Applications &
> Training 15 Fortune Drive NEW Phone: 978-313-5NMR(5667) Billerica MA 01821
> twitter: _at_canklin web: http://www.bruker.com
e-mail: clemens.anklin_at_bruker.com
> ======================================================================
>
>
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