Emily,
This is from the good folks in Farmington, CT:
https://urldefense.com/v3/__https://health.uconn.edu/structural-biology/wp-=
content/uploads/sites/177/2017/10/Resetting_lock_freq_vnmrj.pdf__;!!PvDODwl=
R4mBZyAb0!RqLC_Bvj5e8Ek-5pEkt9WYg3BD96j_xs5McfJzFQM5JFSGAau0O8Y4Nq_pgAF9SR1=
-QmmUE5NuodR3V0APEd4iF6$
I'd start by putting in an easy standard, such as one of your lineshape
samples (99% d-acetone, 1% protonated chloroform), since this will have
a very strong lock signal.
Change the frequency downward in conservative increments, until you can see
that strong lock signal (not a weak one like the sidebands), and try to get
it to the middle of your numerical field.
For Bruker spectrometers, the 'cf' command should access something similar
where you can change the base frequency of the spectrometer.
Ronald Shin
University of Alabama at Birmingham
O'Neal Comprehensive Cancer Center
Central Alabama High Field Nuclear Magnetic Resonance Facility
> From: main_at_ammrl.groups.io On Behalf Of Emily Crullvia groups.io
> Sent: Friday, June 6, 2025 11:44 AM
> To: main_at_ammrl.groups.io
> Subject: [AMMRL] Checking and editing magnet's base frequency on VNMRJ4 #agilent #varian #VarianAgilent
Hi all,
I'm working on a Unity Inova 600 MHz NMR. Recently, the console went offline
due to a power issue. It has since come back online and we still have a
magnet. However, it is experiencing a new problem.
When acquiring a 1H spectra of our D2O standard (90% H2O, 10% D2O), the H2O
peak is extremely broad (presumably due to poor shims) and appears at roughly
4.6 ppm. In addition to this, I cannot get a strong lock signal, even after
sweeping all of the z0 range and phasing it. According to people who have
been at WVU longer than I, it has had problems finding z0 automatically
for years.
I have the instructions for changing the lock frequency, but am wondering if
we are also seeing the effects of magnet drift. Is there a way to check the
magnetic field and if necessary correct it in VNMRJ4?
Best,
Emily
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Received on Sat Jun 07 2025 - 19:57:21 MST