Tom,
Quantitation should be reliable if you subtract a spectrum of a blank sample
from the user's spectrum.
Of course, that will decrease the s/n.
About the shape of the signal: Is your RG too large? A clipped FID could give
you those additional peaks.
Best Regards,
Jürgen
_______________________________________________
Jürgen Schulte, Ph. D.
NMR Specialist
Binghamton University
SN Building, RM 1024
25 Murray Hill Road
Vestal, NY 13850
Ph.: 607-777-4405
Fax: 607-777-4478
schulte_at_binghamton.edu
http://nmr.binghamton.edu/Schulte.html
-----Original Message-----
> From: main_at_ammrl.groups.io <main_at_ammrl.groups.io> On Behalf Of Tom Pratum
> Sent: Wednesday, January 10, 2024 6:24 PM
> > To: main_at_ammrl.groups.io
Subject: [External Email] [AMMRL] 27Al background signal in iProbe
Hello All-
We have a fairly new 400 MHz NEO Nano instrument with a broadband iProbe. One
user is very interested in 27Al, and I note that in this probe there is a
relatively significant 27Al background signal - I have seen 27Al background
signals in pretty much every probe I have ever looked at. I have attached a
plot of the signal (tuned empty probe) as acquired with a 2 usec pulse (around
a 30 degree pulse at this power level), with the sw maxed out at 1.875 MHz, and
8 scans. The central component is around 11 kHz wide.
I find the background signal relatively surprising due to the large number of
components, and I am thinking the appearance could possible be due to one or
more spin 5/2 powder patterns in which only the narrowest components appear due
to how the spectrum was acquired, but really don’t know if that is the
case. These components are not artifacts as they do move with the field.
The user has some pretty broad signals they are interested in quantitating,
and it would be good to remove the central component of this background signal
if possible. I can think of a number of characteristics - such as T2 and rf
inhomogeneity - that could be used to remove the signal, but they would also
likely affect the quantitation to some degree,
Does anyone have any experience in removing this background signal they can suggest?
Thanks in advance.
Tom Pratum,
Southern Oregon University
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Received on Thu Jan 11 2024 - 05:33:10 MST