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

From: Heffron, Gregory J. <gregory_heffron_at_hms.harvard.edu>
Date: Fri, 18 Aug 2023 23:55:31 +0000

Hi Weixing,

Just wanted to say I agree completely with Bernd. I would suggest you use the
deuterated sample. There is a lot of data that demonstrates this sample
is quite accurate,

Greg


Gregory J. Heffron | Director, Biomolecular NMR Facility | Visiting Scientist,
Dana-Farber Cancer Institute | Department of Cancer Biology

Harvard Medical School | 240 Longwood Ave. | Boston, MA 02115 | Tel: 617-335-2929|



[cid:8768e6da-2808-4868-a367-c37d112e83d5]


________________________________
> From: main_at_ammrl.groups.io <main_at_ammrl.groups.io> on behalf of Bernd Simon <simon_at_embl.de>
> Sent: Friday, August 18, 2023 5:36 PM
> To: main_at_ammrl.groups.io <main_at_ammrl.groups.io>
> Subject: Re: [AMMRL] 99.8% MeOD vs 80% Ethylene Glycol

Hi,

you used 99.8% MeOD so you are probably measuring on a sensitive probe. The
shift difference in the (almost) pure Ethylene Glycol is flawed by radiation
damping. You should use deuterated Ethylene Glycol. If you use pure Methanol
you will see a similar effect.

Best regards,

      - Bernd -



On Fri, Aug 18, 2023 at 15:20, Walter Zhang <wzhang1001_at_gmail.com> wrote:

Dear All,
I need to use 80% Ethylene Glycol for high temperature calibration. [cid:18a0a098652ad7999131]

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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Received on Fri Aug 18 2023 - 17:23:06 MST