• Department of chemistry & Biochemistry Home
• NMR Facility Home
• ARX500
  • ARX500 Overview
  • ARX500 NMR Users Rules
  • Operation of 1D Experiment
  • XWIN-PLOT to WORD
• Avance300
  • Avance300 Overview
  • Avance 300 NMR Users Rules
  • Operation of 1D Experiment
• Unity300
  • Unity300 Overview
  • Unity 300 NMR Users Rules
  • Operation of 1D Experiment
  • EZ Procedure for 1D
  • Get program for processing NMR data on PC
• Contact Information

 

 

Nuclear Magnetic Resonance Facility

Instructions For Operating The Bruker ARX 500 MHz NMR Spectrometer

1. SIGN UP IN THE LOG BOOK AND LOGIN
Sign the login/logout notebook near the workstation. Click on your group icon, enter your password.

2. OPEN XWINNMR
Open UNIX shell and type “xwinnmr” at the prompt to open the XWIN-NMR window.

3. EJECT THE CURRENT SAMPLE AND INSERT THE NEW SAMPLE
1) Press Lift On/Off button on the BSMS control unit.
2) Remove the previous sample and spinner turbine from the magnet bore.
3) Insert the new sample tube into the spinner turbine. Carefully, measure the depth of the tube using the sample depth gauge (2 cm). Clean off the sample tube using a KimWipe.
4) Place the sample and turbine into the magnet bore. Once your sample is being held at the top of the magnet by air, the turbine should be floating, the spinner does not get caught on the lip of the spin stack (If this happens, the sample will fall suddenly when the eject air goes off and usually break in the probe).
5) Press Lift On/Off button on BSMS control unit again.

4. SET UP EXPERIMENT
1) Type edc, Enter the dataset name and experiment number (1) and processing number (1), click on Save. The user information should be set to your username and the default directory.
2) Type rpar PROTON all.

5. LOCKING and TUNING
1) Type lockdisp to open the lock window
2) Type rsh bb500 to read the standard shim file
3) Type lock and select the solvent of your sample from the list and automatically set the lock. This takes a few minutes as the BSMS unit toggles through the lock parameters.
4) Press Lock On/Off button to toggle off the lock and view the sweep pattern.
5) Adjust Lock Phase as needed. If the sweep lines are not on same level for forward and back directions, press Lock Phase button, Turn the knob to adjust both sweep baselines to same level.
6) Press Lock On/Off button to lock.
7) With the lock on, the lock gain is adjusted to bring the sweep lines in the upper of the vertical lock display.
8) Typing a then wobb will display the tuning curve. The tuning dip display should be shown on the screen. The tuning and matching indicator lights on the preamplifier should also be lit. Make sure the tuning nucleus is listed as the nuclei you want (small box on the wobb display). If not, click on the wobb-SW button, and then type y to the question about changing nuclei.
9) Locate the proton tuning and matching capacitor wands on the bottom of the probe.
10) Slide the gold tuning stick onto the proton tuning wand (labeled with a T). Slowly and gently turn the stick to feel it lock onto the tuning wand. Turn the stick and watch the response on the preamplifier or on the screen. Adjust the tuning until a single green light is lit in the center of the horizontal display or thf tuning curve is center on the screen. Do not force the stick to turn – you can damage the capacitor.
11) Slide the gold tuning stick onto the proton matching wand (labeled with a M), and use the same procedure to adjust the matching until only green lights in the vertical display are lit or the curve dip touches to the bottom line on screen.
12) Iteratively adjust the tuning and matching as needed.
13) When properly tuned and matched, the dip in the wobb display will touch the bottom line at the cross line. Type stop to stop the tuning.

6. SHIM USING THE LOCK SIGNAL SHOWN IN LOCK DISPLAY WINDOW.
1) Adjust spinner rate (20) using Spin Rate button and the knob on BSMS control unit. Press Spin On/Off’ button on BSMS control unit.
2) Press Z1 button, turn the knob to maximize the position of the sweep lines in the lock display.
3) Press Z2 button, turn the knob to maximize the position of the sweep lines in the lock display.
4) Repeat the Z1 and Z2 until the lock signal will no longer go up.
5) Press STANDBY when finished to prevent accidental change of last selected shim value.

7. SET THE DATA ACQUISITION PARAMETERS
1) If you want to collect necleus other than proton, Use rpar to call up the parameters for other nucleus(such as 2D, 11B, 13C, 19F and 31P), type rpar and choose from the list the appropriate experiments. Click copy all to copy all of the experimental parameters(includes acquisition, processing, plotting, and output files). You will need to tune the probe to each nuclei you are observing, starting with the lower frequency and moving up. Press Spin On/Off’ button to turn off spin before tuning other nuclecus and turn spin on after finishing tuning.
2) Type eda to edit the relevant acquisition parameters in a window, Note that not all acquisition parameters are used. DO not change parameters you do not understand. Scroll to the bottom portion of the acquisition parameter listing. Find the entry called PROSOL. Click PROSOL button and it should now read true (it originally was set to false). The entry directly next to it, exp, should now say “PS DONE” after clicking the PROSOL entry (before clicking PROSOL is was blank) THIS IS VERY IMPORTANT!!! THIS PARAMETER INDICATES THAT THE PROPER POWER LEVELS AND PULSE WIDTHS ARE LOADED IN THE ACQUISITION PARAMETERS. LACK OF THIS ENTRY CAN RESULT IN SEVERE DAMADGE TO THE PROBE (the cost of a probe is $20000-35000). After setting PROSOL to true go to the bottom of the window and save the entry before you make any other changes. Once it is saved then you can go back in to the eda and adjust other parameter.
3) A few acquisition parameters that are routinely changed are (some good starting values):
For proton spectrum:
o1p sw/2 + min ppm center of SW in ppm
td 64k number of data points (time domain size)
ns 16 number of scans
ds 2 number of dummy scans
sw 8000 Hz sweep width in hertz
d1 1.0 delay parameter in seconds
p1 ~14us pulse length in microseconds
Tl0 1dB pulse power level in terms of dB
4) Type rga to automatically set the receiver gain.

8. ACQUIRING DATA
1) Type expt to display an estimate of the total experiment time.
2) Type zg to start the data acquisition. This command overwrites existing data.
3) Type a or acqu to go to the acquisition window and view the FID signal in real-time.
To terminate data acquisition prior to completion of all the scans, type halt to stop at the end of the current scan and store the data.

9. PROCESSING AND PLOTTING
1) Type ef after acquisition finished or type tr then ef during acquisition. Auto phase the spectrum using “apk”. or phase manually: Left click on “Phase” to open phase mode; Left click on PH0 button. While holding the mouse button down, drag the mouse vertically to adjust the zero order phase correction. Left click on PH1 button. While holding the mouse button down, drag the mouse vertically to adjust the first order phase correction. Left click on “Return”, and select “Save & Return”.
2 ) If needed, adjust data acquisition parameters (e.g. increase number of scans) using “ased” and recollect the spectrum. The spectral width and offset frequency can also be automatically adjusted in the utilities display – click the “sw-sfo1” button to adjust SW to the area displayed on screen and set SF to center. Type efp (efp=em+ft+pk, pk: phase correction using stored values)
3 ) To integrate the spectrum, click the “integrate” button to enter the manual integration display: Define each integral region using the cursor. (Left click to bring up or remove the cursor from spectrum, middle click to select the start and end of region, right click to remove marks). To calibrate the integrals, left click the spectrum under the integral to be referenced. The selected integral will now be marked with an arrow. Left click the “calibrate” button and enter the value to assign to the integral. The integrals will be automatically rescaled. Click “Return” and “Save as ‘intrng’& return” to save the defined integrals and close the integration display.
4) To label peaks (Peak picking), Expand the spectrum to display region of interest. Type “pscal” set to “global”. To set the peak-picking threshold: Left click on the “utilities” button. Press YU button to change spectrum vertical scale to cm. Type pscal choose global, click mi, Drag the mouse to set the threshold line at desired position then click on the left Mouse button to set the position (any peaks above threshold line will be included) Click on return button when finished
5) Type pps to display the peak list on the screen.
6) Type setti to open the text box and enter a title or comments. Save and then exit when finished.
7) Type edg to set some plotting parameters
Change plabels to yes (to plot peak frequencies on spectrum)
Click on edplabl then change plunit to ppm or Hz and plcolor to black
integr and ilabels should be set to yes to plot integral curves on spectrum
title should be set to yes if you want a text written on the spectrum
param should be set to yes to plot parameters
click edspect
set cy = 0; this will allow for manual adjustment of spectrum intensity otherwise with cy = 12.5 the computer scales all peaks relative to largest peak
dhei = 11.0 if integrals are to be plotted on spectrum otherwise set to dhei = 13.5 if you don’t plot integral curves
click save when you have made changes
8) Use “view” to display the spectrum as it will be printed (print preview). If needed, adjust the spectrum region using “dp1” and the height of the plot in cm using “cy”. Plot the spectrum using “plot”. Default plotting parameters will include the integrals and peak picking results.

10. LOGGING OFF THE INSTRUMENT PROPERLY WHEN FINISHED.
When finished, Turn off the field lock by pressing the key labeled LOCK. turn off the spinner by pressing Spin On/Off button, press Lift On/Off button on the BSMS control unit and remove your sample from the magnet. Reinsert the standard sample (Repeat Step 3). Lock on the standard (CDCl3).

11. USE“exit” TO CLOSE THE XWIN-NMR PROGRAM.
Log out of the SGI workstation. The login window should reappear, ready for the next user.

12. SIGN THE USAGE IN LOGIN/LOGOUT NOTEBOOK.