Re: [AMMRL] 99.8% MeOD vs 80% Ethylene Glycol

From: Clemens Anklin via groups.io <clemens.anklin=bruker.com_at_groups.io>
Date: Tue, 22 Aug 2023 23:21:12 +0000

The original equations go back to Merbach et al in JMR 46, 319-321 (1982).
Over time they have been refined. The equation for Glycol-d6 is experimentally
determined. The same is true for MeOD 99.8%.

Clemens


On 8/22/2023 12:52 PM, Zhang, Weixing via 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.
[cid:part1.hv0oZlUh.ujVVwL69_at_bruker.com]
[cid:part2.GNJIcd01.iieG6R7Q_at_bruker.com]

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<mailto:main_at_ammrl.groups.io> <main_at_ammrl.groups.=
> io<mailto: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<mailto: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. [cid:part3.ZkWK8mGk.7bYeLFqi_at_bruker.com]

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


________________________________


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==========================
==========================
====================
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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Received on Tue Aug 22 2023 - 16:56:48 MST