Thank you to all who responded to my query. I have taken all your
suggestions into consideration or action, but because this issue only
occurs on a relatively low percentage of samples, it might take some time
to determine if it is fixed with your suggestions.
I had failed to mention that the spectrometer has a Prodigy probe, and that
we normally do not spin samples. Also, I had already used the moist Q-tip
method to clean up the upper barrel, However, I didn't notice any visible
signs of residue on the tip. This method, however, fails to clean the part
of the upper barrel where the narrow stem of the spinner is inserted. The
Q-tip is too broad and won't reach there. So using a 5/8" wooden dowel,
slightly narrower than the spinner's stem, I made a "flat Q-tip" to gently
swab that region (I know I might be touching the top of the probe, so I was
very gentle).
So far, after a few samples, the magnet is happy, but we'll have to see in
the coming days if sample insertion is 100% reliable.
Eugenio
*Eugenio Alvarado, Ph.D.
Director, NMR Services
Chemistry Department, University of Michigan
930 N. University Ave., Ann Arbor, MI 48109-1055.
Voice: (734)-764-9924, Fax: (734)-647-1179*
On Tue, Dec 16, 2025 at 3:53 PM Eugenio Alvarado via groups.io wrote:
> Dear all,
>
> Recently, our Avance Neo 500 with a SampleCase is having more frequent
> random issues with about 10% of samples that don't seat completely
> inside the magnet. The samples lift and descend properly in the magnet
> but sometimes they just don't settle down properly, even after a delay
> of 30 or 45 seconds, causing IconNMR to eject and try inserting the
> sample several times until it gives up. When that happens, not only
> that sample fails, but also the next one in the queue, probably because
> its start time has timed out after the previous attempts. The gas flow
> pressure in the console is set at 4.5 bar and I just changed the "VT gas
> flow limitation" in the BSMS Web Services interface from 700 to 250 with
> just a little improvement. The VT gas flow in standby is 40 l/h and
> for operation it is 400.
>
> Can anyone please suggest any other parameter to adjust to make sample
> insertions more reliable? Or could it be a problem with a valve?
>
> Thanks in advance,
> Eugenio
>
> --
> Eugenio Alvarado, Ph.D.
> NMR Facility Director
> Chemistry Department, room 3500. University of Michigan
> 930 N. University Ave., Ann Arbor, MI 48109-1055.
> Voice: (734)-764-9924
>
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Received on Thu Dec 18 2025 - 11:36:58 MST