Hi all,
Turns out my predecessor(s) fought this problem tooth and nail before finding
a suitable workaround. The artifact is indeed from the carrier frequency. It
crept up long ago in the lab and eventually affected all of our Bruker systems.
This being the first time I've run into it myself I assume some degree of
intermittence. From what I hear it's a common issue many labs have experienced.
It's removable by applying linear prediction in TopSpin processing, and then
in Mnova loading the 1r file to receive the same benefit. There's still some
mystery why this happens at all, but with a fix in place I can live not knowing.
Thank you all for the rapid feedback, your numerous offers to help are highly
appreciated. I've attached an example raw data file here for the several who
were curious to take a look themselves.
Kind regards,
Luke
Luke Fulton, PhD
CHEM BLDG R003
NMR Core Facility Director
Unit 3060
COR2E & Department of Chemistry
55 N Eagleville Road
University of Connecticut
Storrs, CT 06279
email: fko24003_at_uconn.edu
(alias): luke.fulton_at_uconn.edu
mobile: (603) 953-5275
Office: (860) 486-4069
________________________________
> From: main_at_ammrl.groups.io on behalf of Fulton, Lukevia groups.io
> Sent: Thursday, October 3, 2024 5:54 PM
> To: main_at_ammrl.groups.io
> Subject: [AMMRL] Artifact: processing or acquisition?
Hi all,
A user has reproduced a strong singlet centered at o1p in udeft carbon spectra.
I'm reminded of center spectra phantom peaks that appeared on varian's when
number of transients wasn't a power of 2. But those "signals" only contained a
single data point, and in this case the "signal" has plenty of points. It appears
on Mnova, is absent in TopSpin, and we've confirmed independently with multiple
computers. I'm certain it's an artifact rather than sample contents. What I'm
less sure of is whether it stems from the instrument and acquisition conditions,
or file transfer and data processing. We've encountered both sorts of issue
previously. The console's TCU B cable has known problems right now.
If no has heard of this before then I'll push them to repeat the measurement
on a different magnet. They're itching to submit and won't want to chase the
ghost. I just don't want them relying on questionable data.
Kind regards,
Luke
Luke Fulton, PhD
CHEM BLDG R003
NMR Core Facility Director
Unit 3060
COR2E & Department of Chemistry
55 N Eagleville Road
University of Connecticut
Storrs, CT 06279
email: fko24003_at_uconn.edu
(alias): luke.fulton_at_uconn.edu
mobile: (603) 953-5275
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Received on Fri Oct 04 2024 - 10:04:05 MST