Re: [AMMRL] : Puzzle of glucose HSQC

From: Vuckovic, Ivan, Ph.D. via groups.io <vuckovic.ivan=mayo.edu_at_groups.io>
Date: Wed, 04 Mar 2026 00:59:11 +0000

Hi Weixing,

I agree with Clemens — those are indeed HSQC-COSY artifacts, and the additional
peaks correspond to correlations of C-3 and C-5 with proton H-4.

However, the chemical shifts of H-3 and H-5 in your spectrum differ noticeably
from the literature values (HMDB and BMRB). What are your experimental conditions
(solvent, pH, temperature), and what reference you used for chemical shift calibration?

Your resolution in the F1 dimension is remarkable — the HSQC correlation
peaks of C-3 and C-5 are clearly resolved, which is not the case in database
spectra.

For reference, I am attaching a full assignment of glucose HSQC spectra,
along with additional examples of HSQC-COSY artifacts.

Best regards,

iv


________________________________
> From: main_at_ammrl.groups.io on behalf of Anklin, Clemens via groups.io
> Sent: Tuesday, March 3, 2026 3:37 PM
> To: main_at_ammrl.groups.io
> Subject: [EXTERNAL] Re: [AMMRL] : Puzzle of glucose HSQC

Hi Weixing

HSQC's can show COSY type peaks when the acquisition time in the indirect
dimension gets long. Would these peaks by any chance align with the C4
protons? The sequence hsqcedetgpsisp2.4 suppresses these COSY type artefacts.

Clemens

On 3/3/2026 2:38 PM, Zhang, Weixing via groups.io wrote:


Dear Colleagues,

The attached picture shows the HSQC cross-peak of C3 and C5 in natural abundance
β-glucose.

Coupling to the C2 and C4 protons makes C3 appear as a triplet, but I am unsure
what the small peak located ~32 Hz to the right of the main signal represents.

Similarly, for C5 there is also a small peak on the right side, approximately
20 Hz away from the main peak.

I would appreciate any insight into the origin of these additional peaks.

Thank you in advance.

Best regards,
Weixing

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Received on Tue Mar 03 2026 - 18:08:18 MST