NMR Acquisition Procedure Be sure to never lean on the magnet and touch it as little as possible Always log into the log book first by writing your name and the name of your sample. Follow other entries in order to include all information. 1st: Make sure the air column is up, you will know this if you can hear it.  To raise air column you must hit the orange button, then the lift button. (see diagram 1) 2nd: Load your sample into the magnet. You need to first put the blue spinner on your sample. Then you measure the height of the spinner using the depth gauge -- to learn how to do this see Dr. Timm Place the sample in the central column where the air is coming out, your sample will "float" on top of the air column until it is lowered.

*do NOT put the depth gauge in the magnet, if you do you will never be allowed to use the NMR again!!

Diagram #1

Lift	X	X	X
Field	Sweep Amplitude	X	X
X	Lock Phase	Lock Power	Lock Gain
Spin	Lock	Auto Lock	X

Previous 20

Actual 20 or 21

X	X	X	X
Z	Z2	X	X
X	Standby	X	Orange

3rd: Preparing to run the sample. (See diagram 1 for clarification) Press the lift button and the sample will slowly lower into the magnet. Press spin, this will spin the sample. You will know the sample is up to speed when the spin numbers read 20 or 21. Check to see if the lock signal (peak) is centered on the screen.  If not you'll have to adjust the field (click field and use the black knob).  If you are unsure of how to do this find Dr. Timm. Auto-lock: Press auto-lock in order to lock the signal. You will know the signal is locked when the console numbers go back to the original spin numbers and the orange line appears at the top of the page. Once the signal is auto-locked you must lock the signal by pressing the lock button. The signal of the sample must be shimmed in order to get the best signal possible. Shimming Procedure: Read in a Shim file by typing RSH_LAST2004.990 followed by RETURN. Press the lock-gain button, this gives you the ability to move the orange raster (line) down Lower the orange raster by spinning the black knob --- move it down approximately two blue grid lines Now press Z, then use the black knob to move the orange line up and down on the screen: the goal is to get the line as high as possible on the screen. Once it is as high as possible hit the Z2 button and repeat the procedure. You should go back and forth between Z and Z2 as many times as is necessary to get it right but it should only require a few. Standby: There is a button labeled standby that you need to press in order to get out of Z (shim) mode. Then hit the lock-gain button again and spin the black knob until the orange line is at the very top of the screen.

4th: Acquiring a spectrum Set program: Depending on what type of spectrum you would like to acquire (H, C, etc.) Proton NMR: Type RJ_HCDCL3.PAR followed by RETURN (There must be a space between the J and the H) Carbon NMR: Type RJ_CCDCL3.PAR followed by RETURN After this is done and if no one else is using the NMR between your sample runs then you do not have to do this again after the first time unless you are changing the type of acquisition.  If you'd like to change parameters, see Dr. Timm. Type II then RETURN: this process initializes the computer/spectrometer interface Type RGA (automatically sets receiver gain) and then RETURN: wait until the sequence is complete -- it will say:"Auto RG Finished" Type ZG (zero go) then RETURN: After you do this the computer will run through 16 times for a proton NMR and 128 times (these are default numbers for a carbon NMR You can see it counting off at the top of the monitor screen. Name the sample and then hit RETURN: To do this you just type WR_OCMHxxxx.date or WR_OCMCxxxx.date depending on whether you are saving a H or C NMR spectrum.   You have an 8 character limit for the entire name.

5th: Removing the sample at the end of a run: Turn the lock off by pressing the lock button on the console. Turn the spin off by pressing the spin button on the console. Press the orange button then press the lift button. You can then take the sample off of the air column and place a new sample in and repeat the procedure. Be sure to turn off the air column by pressing the lift button a second time before you sign out of the log book. SIGN OUT of the log book.

 

Timm A. Knoerzer email Naz Chem. Dept. Naz. Home Page Last Updated Monday, January 31, 2005 02:35:28 PM