INSTRUCTIONS FOR OBTAINING A ROUTINE ¹H NMR SPECTRUM

IN CDCl₃ ON THE VARIAN 400 MHz NMR (Version 2.1, July 15, 1998)

LOGGING IN:

Move mouse and wait for screen to activate.

Enter user name and password:

user name: your user name (three initials of research director; ex. jls)

password: nmrsparc

Click on spectrum icon to start VNMR.

INSERTING SAMPLE, LOCKING, AND SHIMMING:

In the Input Window, type e to turn on the eject air.

Remove the standard and put your carefully measured and cleaned sample in the probe.

Type i to insert or lower your sample.

Usually sample will begin spinning automatically (20 Hz) and will lock automatically. Look at the NMR400 Acquisition Status window to verify this; you should see Spinner: Regulated and Lock: Regulated. You should wait about a minute to see if it locks automatically.

USING GLIDE TO DO (ALMOST) EVERYTHING

If sample is spinning, but not locked, you may let GLIDE lock and shim the sample for you. The instructions in this box do not allow you to modify any parameters. See the instructions following this box for a more detailed/interactive approach.

Click on GLIDE.

Click on Setup.

For standard proton spectrum:

Experiment: Proton1D

Solvent: CDCl3

Location: 0 (no autosampler)

Sample: Insert

AutoLOCK: Yes **Click on No if sample is already locked

AutoSHIM: Yes

If you want to save data, click on line next to Save As: and type in file name.

Click in text box and enter text (plot does not include the file name, so it is useful to enter it again here, or a notebook number, sample description, etc.).

Click on Setup.

Click on Go. NMR will automatically lock, shim, acquire, process and plot sample.

Click on Exit. Follow REMOVING SAMPLE AND LOGGING OUT instructions.

THE FOLLOWING INSTRUCTIONS DESCRIBE A MORE INTERACTIVE APPROACH TO OBTAINING A ¹H SPECTRUM.

If sample is not spinning:

1. 1.Click on Acqi | Lock

2. Turn spinner on by clicking the ON button under SPIN (or you may need to turn it off and back on again to activate it).

If sample is not locked:

1. Click on Acqi | Lock (and make sure lock is off)

2. Turn up lock power and lock gain all the way (if signal is weak, try turning the lock gain down, then back up again).

3. Adjust Z0 (check to see if it is close to the value on the wall). Click LMB on +/-4 to lower, click RMB on +/-4 to raise. You want to see fewer/no oscillations. Sample is ready to lock when the signal goes up and is flat or angled down.

4. Turn lock on by clicking ON

After the sample is locked, adjust the lock power and lock gain (under Acqi | Lock) so the lock level is about 80%. A good value for lock power is 30 or less. The lock power should be less than the lock gain. Mentally note the lock power, because when you shim, you do not want the lock gain value to go below the lock power value (to avoid saturating).

To shim:

1. Click on Acqi | Shim

2. The shim parameters Z1, Z2, Z1C and Z2C should be listed. If not, click the RMB on the arrow and select coarse Z. For routine samples you should only need to shim on Z1C and Z2C!!

3. Begin optimizing the lock signal by increasing and decreasing Z1C by 16’s, then 4’s and 1’s. Response on Z2C is often very flat, so it is usually adequate to adjust by 16’s then 4’s. After you adjust Z2C, go back and adjust Z1C again.

4. Click CLOSE.

ACQUIRING, PROCESSING AND PLOTTING:

Click on GLIDE.

Click on Setup.

For standard proton spectrum:

Experiment: Proton1D

Solvent: CDCl3

Location: 0 (no autosampler)

Sample: Insert

AutoLOCK: No **you need to click on No

AutoSHIM: No **you need to click on No

If you want to save data, click on line next to Save As: and type in file name.

Click in text box and enter text (plot does not include the file name, so it is useful to enter it again here, or a notebook number, sample description, etc.).

Click on Setup.

Click on Acquire. Default values are okay. Check with research director for modifications.

Click on Do.

When screen says DONE, click on Custom, then click on Process.

Click on Process button. Spectrum will appear. (**If adjustments in the appearance of the spectrum or the integral are desired, click on Glide in the permanent menu to hide the Glide menu bar. Do not exit Glide. Instructions for adjusting the phase, integral and peak threshold are provided at the end of this document.)

Click on Custom, then click on Plot. Default values are okay, again check with research director for possible changes.

Click on Do Plot.

Click on Exit.

REMOVING SAMPLE AND LOGGING OUT:

Type e to eject sample. Remove sample from magnet. Replace standard (EB in CDCl₃).

Type i to turn off eject air. Make sure standard sample is spinning and locked by looking at Acquisition Status window. If not, follow previous instructions on spinning and locking.

Type exit. (Or click on Main Menu | More | Exit VNMR.)

Click on EXIT sign on CDE tool bar. Click on OK on logout confirmation.

ADDITIONAL INFORMATION ON PHASING, INTEGRATING AND SETTING THE PEAK THRESHOLD

PHASING

If you use Glide to process your data, your spectrum will be autophased. If you do not use Glide, you can autophase the spectrum using the command aph.

If there are still problems with the phase, you may phase the spectrum by hand (for details, see p 228-229 in Getting Started):

1. Click on Phase.

2. Click the LMB on a spectral region of interest toward the right side of the spectrum, about halfway vertically up the screen. (The middle mouse button adjusts the vertical display, if you want to increase the y-scale.)

3. Click and drag the LMB up and down to phase the spectrum. (For finer adjustment, use RMB.) This adjusts the zero-order phase.

4. Now click the LMB on a region of the spectrum near the left edge of the display.

5. Click and drag the LMB to phase. This adjusts the first-order phase.

6. To exit phasing mode, click another menu button (Cursor or Box is a good choice).

INTEGRATING

1. Click on Part Integral (you may need to click through Full Integral and No Integral to get there). Integral may be y-scaled with the middle mouse button.

2. Click on Resets. Add resets with LMB. Remove resets with RMB. If you have two integrals very close together that you want to split, you need to click the LMB twice. Click on another menu button (Cursor or Box is a good choice) to turn off Resets.

3. To set the integral value, click the cursor on the integral line you wish to set and click Set Int. Type in the desired value for that integral region. (You may need to click Flip twice to put spectrum back on top of dg window.)

4. If you want to adjust the appearance of the integral (for example, if it slopes up too much) click on Lvl/Tlt and adjust by clicking and dragging the LMB for level and the RMB for tilt. Click Lvl/Tlt again to turn off.

SETTING PEAK THRESHOLD FOR PEAK PRINTOUT

1. Click on Th.

2. Move the horizontal threshold line to the desired height by clicking and dragging the LMB.

3. Click Th again to turn threshold off. (See dll and pll commands below to print list.)

To retrieve good shim file:

rts(‘goodshim’) (goodshim will always be the name of the updated shim file)

su

To save your current shim parameters:

svs(‘filename’)

Other useful commands:

aph autophase

cz clears reset points on integral

dll displays line frequencies and intensities above the threshold

ds display spectrum

inset displays the part of the spectrum between the two cursors in ds as an inset

pll plot list of lines (follow by page command to eject page from printer)

vsadj vertical scale reset

wft weighted fourier transform