Safety
The magnetic field extends roughly 5 feet from the center of the magnet. Do not bring any cell phones, laptops, floppy disks, credit cards, or mechanical watches near the magnets as they will be permanently damaged. Do not bring metal objects near the magnets as they can damage the instrument or cause personal injury. Please refer to the NMR Safety Guidelines for complete and detailed information.


Logging In
After entering your login name and password, you will be asked for your account number. This is the charge number you use in the stock room.


Starting the VNMR Software
To start the VNMR software click on the VNMR icon (the one that looks like an NMR spectrum) on the menu bar at the bottom of the screen.


Loading the Parameters
In your folder there should be some parameters for ¹H and ¹³C (e.g. h1parmnew.200, c13parmcdcl3.200). There are more parameter files in the vnmr1 folder - click on File, Set Directory, Parent, select vnmr1 from the list and then click on Change. To load the parameters that you need, click on Main Menu, File, select the parameter file from the list and then click on Load. Be sure to load the parameter file for the correct nucleus and solvent. If you want to load the shim values, type load='y'. If you need to change the solvent, type solvent='solvent name'. Type su to set up your changes.


Loading the Sample
Insert your tube into the spinner and check the tube height using the depth gauge. Click on Acqi to bring up the acquisition window. Click on LOCK to open the lock window and turn the spinner off. Click eject to eject the standard and place it in the holder on the wall. Place your sample in the barrel on the air cushion and then click insert. Turn the spinner back on.


Locking and Shimming your Sample
First make sure the sample is spinning; the spin counter should be green and showing a rate of 20 Hz. Now make sure that LOCK is turned on. This locks onto the deuterium signal of your solvent to stabilize the magnetic field. The lock indicator should be green, and the signal should look like a square wave:

If the lock level is very low or you do not see a square wave:

1. Raise the lock power and lock gain values to the maximum by right clicking on the buttons. If this doesn't work, go to step 2.


2. With LOCK turned off, make positive or negative adjustments (right or left mouse clicks, respectively) to Z0 until you see the square wave. Turn LOCK back on. The lock signal and square wave may reach a maximum. Lower the lock power and lock gain until the square wave becomes visible again; the lock power should be about 10 less than the lock gain. Always keep the lock level above 30 or you will lose the lock signal.

The square wave should be positive (like the picture above). If it is negative, adjust the lock phase until it is positive. Optimize the lock phase by making positive or negative adjustments until you find the maximum lock level.

To shim on your sample, click on SHIM to bring up the shim menu. The coarse shims come up by default, but the only shims you will need to adjust are the fine shims: Z1, Z2, Z3, Z4, and Z5. To get to the fine shims, click on the shim button under the lock level bar.

1. Make positive or negative adjustments to Z1 until you reach a maximum lock level.


2. Adjust Z2 until you reach a maximum lock level (as in step 1).


3. Repeat steps 1 and 2 until there is no increase in the lock level.


4. Cycle through the shims (Z1-Z5) in this fashion until there is no improvement in the lock level.


5. If for some reason you exceed the range of the Z1 or Z2 shims, move them back to the middle and adjust the coarse shims Z1C or Z2C to bring the lock level back up. Use Z1 or Z2 for fine tuning.

If you need more information, please refer to the User's Handouts titled "Locking" and "Shimming."


Setting Up Your Experiment
The default parameters are for the MERCURY Vx 200 MHz spectrometer and are good for most experiments on that instrument. The only ones you might want to change are sw, pw, d1 and nt.

Acquisition Parameters

Parameter	Default	Description
sfrq	199.972	Spectrometer Frequency in MHz. This is a NOT an adjustable parameter.
tn	H1	Transmitter Nucleus. It is set to 1H and is not adjustable.
sw	3000.3	Spectral Width in Hz. The default value of 3000.3 will give you a 15 ppm window. (3000.3 Hz/199.972 MHz = 15 ppm). The window must be large enough to accommodate all possible signals from your sample. If you have a strangely placed peak or a peak which cannot be phased, the peak is most likely outside of your sw and has folded into the opposite end of the spectrum. For example, if your spectral window is set from 10 to -5 ppm, a signal at 12 ppm would fold and show up at -3 ppm. Conservative settings for the spectral window are an sw of 15 ppm spanning from 13 to -2 ppm. If you need to make adjustments to your spectral window, follow the procedure described in the User's Handout titled "Setting the Spectral Window."
at	2	Acquisition Time in s. This is the length of time that the FID is collected for each transient (See the figure at the end of this section). In practice this parameter is best adjusted indirectly by changing sw or np and letting the computer calculate at accordingly.
np	12002	Number of Points. For digital storage, a FID is represented by data points. np must be at least twice sw. A value of 4*sw is recommended for good digital resolution.
fb	1600	Filter Bandwidth. This parameter is automatically adjusted by the computer when sw is changed.
bs	4	Block Size. bs represents the minimum number of transients that need to be acquired before you can perform a weighted Fourier transform of your spectrum in the foreground while acquiring more transients in the background. The instrument only saves data in completed blocks. In practice, a bs of 4 is advisable to assure that at most only three transients are lost when acquisition is stopped or aborted.
ss	0	Steady state transients. ss is the number of times the instrument will perform the desired pulse sequence without data collection prior to carrying out the acquisition of real data (sometimes known as dummy scans). This is done to magnetically prepare the spins in the sample prior to acquiring an NOE measurement. ss is usually set to zero unless you are doing an NOE experiment.
tpwr	52	Transmitter Power in dB. This is the pulse power. It can be adjusted but MUST NOT EXCEED 60.
pw	18	Pulse Width in μs. This pulse is applied just prior to acquisition (See the figure at the end of this section). pw = 18 is approximately a 60° pulse for proton. For some experiments it is necessary to have a well-calibrated 90° or 180° pulse (e.g. T1 measurement by inversion recovery). If you need to calibrate the pulse time for your experiment, refer to the User's Handout titled "90° Pulse Calibration" for instructions. When the instrument cannot adjust the receiver gain because your signal is too strong, a message about ACD overflow will appear on the screen. To fix this, lower the pw. The coils detect the projection of the net magnetization of your sample in the x,y-plane. A shorter pw will give a smaller angle, and thus reduce the projected magnetization detected by the coils. Another advantage of a smaller pulse angle is shorter relaxation time to the pre-pulse magnetization.
p1	0	First Pulse Length in μs. In multiple pulse experiments (e.g. inversion recovery), this is the length of the first pulse.
d1	1	First Relaxation Delay in s. This is the delay time before the first pulse in both single and multi-pulse experiments (see the figure at the end of this section). The relaxation delay is very important. If it is too short, the pre-pulse magnetization will not be restored prior to the next pulse and the resulting spectrum will not provide quantitative data. If the integrals for your spectrum do not make sense, increase d1 and re-acquire. The optimum d1 is at least 5 times your longest T1 time.
d2	0	Second Relaxation Delay in s. This is the delay time between pulses in a standard two-pulse sequence.
tof	14.8	Transmitter Offset Frequency in Hz. tof is the shift in frequency required to put the carrier frequency in the middle of sw. Different solvents will have different values of tof due to their deuterium chemical shifts. To optimize tof, follow the procedure in the User's Handout titled "Setting the Spectral Window."
nt	4	Number of Transients. This parameter sets the number of FIDs to be acquired in the experiment. It should be set as a multiple of 4; 40 is good for most research samples. The more scans you take the better the signal to noise ratio (S/N) will be. S/N increases as the square root of the number of transients. This means that if you wish to double your S/N you must collect 4 times as many transients.
ct	0	Completed Transients. This shows how many scans have been completed during your experiment. It is updated by the computer during acquisition.
gain	Not used	Receiver Gain. This parameter represents the amount of amplification of the signal. gain='n', or gain not used, is actually auto gain and the computer controls the level. In some experiments, such as arrayed experiments, auto gain cannot be used. gain='y' uses a fixed value.

Sample Parameters:

Parameter	Default	Description
solvent	CDCl3	To change the solvent, type solvent='solvent name' using the appropriate name or formula for your solvent.
file	h1parmnew1.200.fid	This tells you the filename of the current experiment.

Decoupling Parameters:
Please refer to the User's Handout titled "Decoupling."


Processing Parameters:

Parameter	Default	Description
lb	0.10	Line broadening. Sets artificial line broadening and exponential weighting along the directly detected dimension.
fn	32768	Fourier number. Selects the Fourier number for the Fourier Transform along the directly detected dimension. If fn < np, only fn points are transformed. If fn > np, fn minus np zeros are added to the data table (zero filling).

Acquiring a Spectrum
Before acquiring data, you MUST lock and shim on your sample.

• After optimizing the parameters, it is always best to setup your changes by typing su. To run your experiment and automatically perform a weighted Fourier transform after completing nt FIDS, type ga (go acquire). If you do not want the console to automatically perform the transform type go instead.


• There are two ways to abort the acquisition prior to completion of nt. Typing sa will stop the acquisition but allows you to continue by typing ra (resume acquisition). sa/ra can be thought of as a pause function. Clicking on Abort Acq will abort the experiment such that it cannot be restarted.

Transforming Your FID
After completion of a block of transients, you can Fourier transform the acquired FIDs by typing wft (weight and Fourier transform). This can be done many times during acquisition. After execution of the command your spectrum will be displayed on the screen. To get the full window, type f.


Processing Your Spectrum
The middle mouse button controls the vertical scale (vs). To increase the vs hold down the button and drag the mouse up. wp controls the width of the plot, and sp controls the start of the plot. The left button controls the left cursor and the right button controls the right cursor. wc controls the width of the chart (or window). The ds command will display the spectrum.


Phasing Your Spectrum
To phase the spectrum type aph to automatically phase the spectrum. To manually phase the spectrum click on Phase and then click on the peak that needs to be phased. The left mouse button controls the course phase and the right mouse button controls the fine phase.


Creating a Scale and Changing the Axis Units
To place a scale under the spectrum, type dscale for display scale or click on the Dscale button. To change the units of the scale type axis='h' for Hz and axis='p' for ppm.


Referencing the Solvent
To reference the solvent, zoom in on the solvent peak by surrounding it with the two cursors. Then click expand. Place a single cursor on the solvent peak, and type nl for nearest line. This will center the line in the middle of the peak. If the chemical shift is incorrect click on Ref or type rl(#.##p). (e.g. For CDCl3 you would type rl(7.27p)).


Integration
There are three integration modes: part, full, and none. By clicking on Integral you can change the mode that you are in. The "part" mode lets you break up the integral. The "full" mode gives you a single integral.

• Breaking up the integral. First click on Part Integral. When the integral comes up, type cz to clear the memory (clear zeros). Click on Lvl/Tlt to interactively adjust the integral line with the mouse. Then click on Resets. To break up the integral, left click on the left side of a peak then the right side. Repeat this until you integrate all of the peaks that you want. The ins command is used to normalize the areas. By typing ins=100 all of the areas on the screen will add up to 100. If you want absolute areas, type ins=1 and insref=l. (Note: you can use insref=le-5 to move the decimal point.)


• There are two ways to display the integral areas:
1. Typing dli (display list of integrals) displays the areas in the text window. To print out the list of integral areas type printon dli printoff.
2. To display the areas on the spectrum, first adjust the vertical position by typing vp=12, then type dpirn for normalized areas or dpir for absolute areas.

Peak Picking
Press the Th button and use the left mouse button to raise or lower the yellow line. Type dpf (display peak frequencies) to label the peaks. All peaks above the line will be labeled.


Creating a Text Label
To create a text label type text('your label').


Configuring the Plotter
On the 200 MHz NMR, there are two printers that you can use. For standard size paper use the printer next to the computer (LaserPlot6L). For the large 11x17 paper choose the printer in the 3rd floor NMR room (LaserPlot800011x17). To select the printer, click on Main Menu, More, Configure, Select Plotter. This changes the selected printer to the next option. The current printer will be displayed in the text window above the command line. Repeat this entire process until you've selected the printer that you want.


Printing your Spectrum
To print out the spectrum, type the appropriate print commands ending with page.

pl	Plots the spectrum
pscale	Prints the scale
pir	Prints the integral areas
ppf	Prints the peak frequencies
pap	Prints all of the parameters
ptext	Prints the text label
page	Gives you a new page

Saving your FID
You can only save FIDs in your own folder. If you are in a different folder, return to your own folder by clicking on Main Menu, File, Set Directory, Home. To save your FID, type svf (save FID). It will ask what you want to call it. Type the filename followed by the following suffixes:

.200	200 MHz spectrometer
.qnp	400 MHz spectrometer
.idp	500 MHz indirect detection probe
.swp	500 MHz switchable
.bbp	500 MHz broad band probe

Joining Different Experiments
To join a different experiment, type jexp#, where # is the experiment number.


Logging Out
When you are done, eject your sample and insert the ethyl benzene standard. After locking and shimming, take 4 scans to check the resolution of the TMS peak. Zoom into the TMS region, the peak should be a singlet. Place the cursor on the TMS peak and type nl then dres (display resolution). If the resolution is below 1 Hz you can log out. If not, you must reshim until the linewidth is < 1 Hz.

To log out, click on Main Menu, More and Exit VNMR. This will get you out of the VNMR software. To log off the system, click on the EXIT button on the menu bar at the bottom of the screen. Be sure to sign the log book and appropriate charge sheet.