User Guidelines for Solution NMR Spectrometers

If you are a user of any of the solution NMR magnets, please take time to read the following material. There are only a few rules but I expect them to be followed. Constructive comments and suggestions are always appreciated. Copies of this note will be placed in the NMR notebooks.

A. User Guidelines

A1.  Notebooks are provided for the 500, 600 and 720 NMR spectrometers. ALWAYS sign them with the mini­mum of your name and starting and ending dates.

A2.  ALWAYS measure the signal/noise on the ethyl benzene s/n standard and record this value in notebook. Also note the probe serial number. The reasons are endless for making this rapid measurement (< 15 minutes) on a routine basis. If you do not know how to do this, please ask.

A3.  When applicable, record ¹H, ¹³C, and ¹⁵N pulse lengths and associated power levels. This will provide use­ful information about long term amplifier performance, tune and match of the circuits, etc.

A4.  Note anything that is unusual, e.g., computer reboots, unusual noises, fans not working, other hardware or software problems, etc. Please send me an E-mail if any problems occur.

A5.  When you are finished recording data, ALWAYS place the ethyl benzene s/n standard in the probe and indi­cate the ending date in the notebook. Finally, unless other arrangements are made, reserved NMR times begin and end at 9 am on the first and last scheduled days of your time blocks.

A6.  Probes are very expensive and need to be carefully installed and stored, at this time I would prefer to handle all probe swaps. Please plan ahead if you anticipate having to change probes during the weekends or over­night.

A7.  NMR data should not be stored on the workstation disks. Please copy the raw data to your personal worksta­tion and then delete the large fid file. The workstations are backed up daily by the NHMFL system adminis­trators but you still should have personal backups of your data. I usually save all my fid directories (minus fid files) in their original locations for future access to the acquisition parameters and shims.

A8.  Limited remote access to the spectrometers will be possible in the near future. You will have to send me your workstation IP address by E-mail when you want this access. Tim Logan and I will determine who will have this access. Since we would prefer most users to work at the spectrometer console this will not be freely available to most users.

A9.  The air pressure at the wall regulators should not be changed from the current values: shim (or body) air, 8psi; VT air, 25-32 psi; and leg support, 60 psi. The air flow rate for cooling and VT air be about 15 Liters/min. Excessive VT air pressure and flow rate will increase the noise value. If air pressure is insufficient to eject the NMR sample, check that the upper barrel is seated against the probe by carefully pushing downward on the top of the upper barrel. As a last measure, increase the VT and cooling air flow rates until the sample is ejected and then make sure to return the flow rates to about 15 Liters/min.

B. NMR Spectrometers and Workstations

The workstations at the 500, 600 and 720 spectrometers have been upgraded to Ultra-5 Sparc workstations run­ning Solaris 7 and version 6.1c VNMR software. I’ve assigned a contact person for each of the spectrometers. They will be responsible for routine testing and maintenance, this opportunity will also provide them additional NMR training. The contact persons are Vedrana Marin (500 MHz, telephone 644-2286, e-mail ved_marin@yahoo.com) and Kersten Schroeder (600 MHz, e-mail kschroed@chemmail.chem.fsu.edu).

All spectrometer consoles have been thoroughly cleaned, i.e., filters and screens removed and washed, inside of console vacuum cleaned and all other surfaces washed and wiped dry. All panels that had been removed from backs of spectrometer consoles have been replaced to their original positions. Removing the panels will lead to inadequate cooling of the RF electronics and should not be done without first notifying me.

The following spectrometer repairs have been made or are in progress: 500, the VT solenoid has been bypassed; 600, cooling fans have been replaced on the two RF amplifiers; 720, the low band preamp electronics have been repaired, allowing direct detection on the low band channel and their tuning and matching. The RF amplifier originally on the third channel has been repaired.

I have inventoried and tested many of the probes that are currently available and summarized the results on the page corresponding to each spectrometer — see the links below.

500 MHz solution NMR spectrometer
600 MHz solution NMR spectrometer
720 MHz solution NMR spectrometer

At each of the spectrometers a directory is present (/export/home/vnmr1/probes/) containing all fids and shims for these results. Directory names are constructed from the probe name and serial number. Please feel free to start with these shim sets when setting up your experiments. Since this table is still incomplete, users are welcome to spend some of their time to upgrade the results.

— Jack Skalicky
Assistant Scholar Scientist