INTRODUCTION
to the Bruker AM-300
NMR Spectrometer
Training and Operators manual
Tufts University
Dept. of Chemistry
62 Talbot Avenue
Medford, MA 02155
by: M. d'Alarcao
D. Parkinson
C. Amass
D. Wilbur
rev 1/11/02
Bruker AM-300 Training and Operator’s Manual
Rev 1/11/02
Table of Contents
Subject
Table of Contents
General Procedures
1.
Preliminary Notes
2.
Loading a sample
3.
Locking the Instrument
4.
Shimming the Magnet
Running a 1H Spectrum
5.
Setting the Parameters
6.
Acquiring the Spectrum
7.
Transforming the Data
8.
Phasing the Spectrum
9.
Setting the Reference
10.
Plotting the Spectrum
10A.
Changing O1 and SW for increased resolution
11.
Integrating the Spectrum
Homonuclear 1H decoupling: 1H {1H sel.}
12.
Setting the Frequency to be Irradiated
13.
Setting the Decoupler Power
14.
Acquiring the Decoupled Spectrum
Observing 13C {1H}
15.
Setting the Parameters
16.
Starting, Stopping the Acquisition
17.
Transforming and Plotting the Spectrum
18. Naming & Manipulating Files
19. Rebooting the Computer
20. Leaving the Spectrometer
21. Other Useful EP Commands
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General Procedures
1.
Preliminary Notes
A. This manual is a condensed and incomplete account of instrument usage. For additional
information, see AM-300 Users Manual, and DISNMR Reference Manual. These manuals are available
in the NMR room (M-002)
B.
All users should sign the logbook before they do anything else.
C.
The screen intensity is controlled by the black knob to the lower left corner of the screen. The
screen should be left on, but the intensity should be turned down, when the instrument is not in use.
Vertical size (height) of any object on the screen may be controlled by the two black buttons to the left of
the console marked 'vertical display'.
D. The computer software is organized to allow work in three different 'Jobs'. The Job currently being
accessed by the terminal is noted at the top of the screen, and by the command prompt (e.g. '1' when in
Job #1). The current job may be changed at almost any time simply by typing the number of the desired
job. If you keep the method of using Job #1 for running the experiment, Job #2 for transforming and
plotting the experiment, and Job #3 for reading in or plotting other spectra while Job #1 is running, you
won't get mixed up.
E.
Within each Job there are five possible types of screen display pages (or subroutines): spectrum,
acquisition parameters, plotting parameters, automation parameters and processing parameters. Hitting
the 'esc' button again and again will allow you to cycle through the spectrum and parameter pages. Note
that it is not necessary to change the screen display to a parameter page in order to change the value of a
parameter listed on that page. Any parameter may be changed from any page.
F. Parameters are changed by typing the two letter code for that parameter followed by <RTN>. The
computer will respond by printing the current value of that parameter. Now, simply typing the new value
of the parameter followed <RTN> by will replace the old value with the new value. <rtn> alone will
accept the current value.
G. Within the spectrum screen there are three types of displays available: spectrum only, lock signal
only, or spectrum and lock together. Typing <CTRL>L will cycle though the possibilities.
H. A grid may be superimposed on the spectrum by typing <CTRL> D. Typing this again will remove
the grid.
I. The unit to the right of the keyboard consists of an array of buttons, one knob and one LED display
containing two numbers, and controls a wide variety of probe functions including sample raising and
lowering, spinning and shimming. Pressing of the buttons has three effects in general: a) a light goes on
above that button indicating that is operating or selected, b) the LED display now monitors that button's
value, and c) the knob controls that button's value. The orange button is a shift key and activates a
second function printed in orange below the button.
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2. Loading the Sample
A. NMR samples are prepared in a 5 mm sample tube as a solution in a deuterated solvent, since the
instrument uses a deuterium lock. (An unlocked spectrum may be run on any sample by running the
spectrum with the sweep button off.)
B. The probe should contain a sample at all times. When you arrive at the instrument with your research
sample, you should remove the standard sample from the magnet and replace it with your sample as
follows:
-Press the LOCK button to unlock the instrument. The light over this button will go off.
-Press the SPIN button to stop the spinning of the sample. The light over this button will go off.
-Press the ORANGE button (shift) followed by the LIFT button. The standard sample should rise out of
the probe on a stream of air. Remove the standard sample from the top of the probe. Remove the standard
from the spinner.
-Place your sample tube in the spinner and adjust the depth of the tube within the spinner by using the
depth gauge.
- Place your sample in the top of the probe. Do not release the sample unless you are sure it is supported
on the air current.
-Press the LIFT button again. Your sample should slowly lower into the tube as the air stream decreases.
Press the SPIN button.
C. The rate of the sample spinning should be 20-25 rps. To check this:
-Press the SPIN RATE button. The LED display will show two numbers, the one on the left is the
programmed spin rate and the one on the right the actual spin rate.
3. Locking the Instrument
A. The lock gain and power should be adjusted to give a strong lock signal. To do this:
-Press the LOCK POWER button. Turn the knob until the current lock power is about 30 for the 5mm
INV probe, 35 for the 5mm 19F probe and 40 for the C13 and QNP probe for the unlocked state. The
power is automatically lowered when lock is achieved to 75% of these values. Similarly, press LOCK
GAIN and adjust this to about 100. These settings assume d-chloroform, other solvents adjust lock signal
peak to mid scale.
B. You should now see a continuous wave deuterium NMR spectrum of your solvent. This should be a
trace across the screen with the signal in the middle of it. If it is not visible press the FIELD button and
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adjust the field while looking for a peak. Currently, d-chloroform will be found around 5200 and dacetone near 4200. Make sure the signal peak is upright. It is not, adjust the lock phase as follows:
- Press the LOCK PHASE button and adjust the knob until the signal is as upright as possible. The top
of the lock oscillation should be at the same height as the lock sweep wave traces on both scans (left to
right or right to left).
C. Once the solvent’s deuterium signal is phased you may proceed to lock it as follows:
- Press the LOCK button and see if the signal rises to a high level and the lock button light stops flashing
and stays on. If this fails to happen you may try the second method.
- Press AUTOLOCK. Watch the lock signal carefully. When the instrument finds the lock trace, it will
quickly rise to the top of the screen. (It may actually disappear off the top.) At the same time the light
over the LOCK GAIN button will begin flashing. This process may take from a few seconds to a few
minutes depending on the strength of the lock signal. Press the LOCK button, then press the ORANGE
(shift) button followed by the LOCK GAIN button. Now the light over the LOCK GAIN should be off
and the light over the LOCK button should be on. The light over the LOCK should remain on as long as
the instrument is locked. If it begins flashing, the instrument has fallen out of the locked mode and it
should be relocked. After lock is achieved adjust the trace to the top part of the screen by lowering the
LOCK GAIN.
4.
Shimming the Magnet
To obtain a high resolution spectrum it is essential that all parts of the sample are exposed to the same
magnetic field. Auxiliary gradient coils, called shims, have been installed around the probe to allow the
user to adjust the homogeneity of the magnetic field to fit the sample. These are named according to the
3-D Cartesian space which they govern. (e.g. X, Y, Z, Z2, etc.) The homogeneity of the field is generally
assessed by the intensity of the lock signal, the more intense the signal the better the field. In practice,
the shims most likely to require adjustment are the Z, Z2 and Z3. To adjust the homogeneity by hand
proceed as follows:
- Adjust the LOCK GAIN until the trace is in the top two squares of the grid. Press the Z button. Turn
the knob (slowly) to maximize the lock signal. Repeat for the Z2 button. Continue to alternate between
these buttons maximizing the lock signal each time until no further improvement can be seen. You may
have to adjust the LOCK GAIN if the trace goes off the screen.
-If the sample must be shimmed to highest standards, adjust the non-spinning shims by pressing the SPIN
button and waiting until the sample stops spinning. SPIN RATE can be used to monitor this. Raise the
lock level by adjusting the lock gain until the level is in the upper half of the screen. Now press the X
button and use the knob to adjust the lock level to maximum. Then press the Y button and repeat this
procedure until no further improvement is possible. Start the sample spinning again by pressing the SPIN
button and repeat the Z and Z2 shimming as above. When the magnet is adequately shimmed, press the
STANDBY button. For instruction on adjusting higher order shims consult with the nmr manager.
B. Automated computer controlled shimming is available. See the DISNMR Reference Manual, Shim
section.
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Running a 1H Spectrum
5. Setting the Parameters
A. Data files containing typical parameters for a proton spectrum are stored in the hard disk for easy
access. To retrieve these:
- Type RJ H1 <rtn> (read job). Typical proton parameters are stored in this file. Now type PJ
H1<rtn>. This loads typical processing parameters like the current TMS reference frequency.
- Now type II <rtn> to initialize the hardware interface.
B. A complete list of the two letter code for each parameter may be found in the manual. Some of the
commonly varied parameters are: number of scans (NS); spectral width (SW); time domain points (TD);
number of frequency domain points (SI); acquisition time (AQ); and the receiver gain (RG). The
following facts should be considered when making a choice of acquisition parameters.
-The signal to noise ratio (S/N) will increase proportionally to the square root of the number of scans.
Therefore to double the S/N you must use four times as many scans.
-The number of scans has no effect on the resolution (i.e. the ability to distinguish between two signals
which are close in frequency). In fact it can reduce it if drift occurs during a long acquisition.
-The maximum resolution obtainable is called the data point (digital recorder) resolution and is equal to
the frequency range being observed (SW) divided by the number of data points or spectrum intervals
(SI). This assumes the shim is good enough to support the resolution required. It is important to examine
the Hz/pt. in the acquisition screen. You need 3 to 5 pts for the line width you wish to resolve. Thus if
you desire 1 Hz resolution Hz/pt should be .2 to .3.
C. The last parameter to be set is the receiver gain (RG). To set this gain type RGA <rtn> (receiver
gain adjust). The computer will automatically take a few sample pulses and alter the RG between each.
When the best value is found, the computer will type out AUTO RG FINISHED. You may see this
value by typing RG <rtn>. If you wish to select another number then type in the new number which you
want and then type <rtn>. Do not increase the value, but you may decrease it.
6. Acquiring the Spectrum
A. To start the acquisition:
- Type NS <rtn>
and type the number of scans you want: 1, for one scan; or a multiple of 8 for a longer accumulation; or
if you wish it to run forever then set it to -1; then type <rtn>.
Type ZG <rtn> to start the acquisition.
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B. The acquisition will automatically end when the number of scans taken equals NS. However if you
have chosen -1 or wish to stop it prematurely or abort the run then you will have to type: (control) H
<rtn>. This will stop it on the next transient.
7. Transforming the Data
A. When the acquisition is finished the data is present in the time domain representation, called a Free
Induction Decay (FID). We now must Fourier Transform this data to obtain the normal 1D spectrum.
Before transforming, we usually multiply the data by an exponential function to reduce some of the
background noise or alternatively gain some resolution if the spectrum has a very high signal to noise
ratio already. This is done by setting LB to a positive number which will broaden lines (LB =1 makes
narrowest line 1 Hz wide) and decrease noise or a slight negative number which will increase noise but
sharpen lines.
Then transform the data by typing:
BC;EM;FT <rtn>
or as a short form, you can type: EF <rtn>
Note:
BC = base line correction function
EM = exponential multiplication function with LB determining the decay rate.
FT=Fourier transformation of data
8. Phasing the Spectrum
A. The transformed spectrum usually will not have all the signals perfectly upright in an absorption
phase.
To correct this:
-Type EP <rtn>. This command results in entry into the expanded view mode. In this mode the
displayed region of the spectrum is controlled by the knobs to the left of the console. Knob A controls the
center frequency. Knob B controls the width (or expansion) of the spectrum. Knobs C and D control the
cursor. When the cursor is not on the screen, an arrow head at the bottom of the screen will show which
way to turn the Knob C to bring the cursor on screen.
Zoom in on a prominent peak, preferably near one end of the spectrum. Hit the C (with no <rtn>) key
and put the cursor on the top of it with Knob C and then type: P (with no <rtn>).. Use Knob C to phase
this peak upright, and then use the A knob to move through the spectrum to the signal which is farthest
away from the first signal and phase this signal with Knob D. Look back through the spectrum and
adjust either C or D or both Knobs until you are satisfied with the spectrums' phase. If the C or D control
knobs can not move far enough for the necessary adjustment, <CTRL>C or <CTRL>D will reverse the
particular controls’ movement. Continue the adjustment. If some signals can not be phased they may be
folded back from outside the acquisition range. Try reacquiring with a larger SW value. Note any peaks
that move as a result. They are probably the folded ones.
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-When you are content with the phase of the signals then type: M (with no <rtn>) to memorize this phase
into the computer memory.
9. Setting the Reference
A. The spectrometer cannot provide an exact chemical shift without being calibrated to a standard
(usually TMS). It is therefore necessary to find its signal using Knobs A and B and setting its chemical
shift value. While in the EP mode, use Knobs A and B to find the reference signal. Use Knobs C and D
to put the cursor on the top of it. When the cursor is properly positioned type G. The computer will
respond by typing the current ppm value for the cursor. Type the correct ppm value for the standard (e.g.
0.0 ppm for TMS; 7.23 ppm for CDC13) followed by <rtn>. A chart of values for various solvents is
on the console.
10. Plotting the Spectrum
Place paper in the HP-7550A plotter. Press Load/Unload. Either 8 ½ x 11 or 11 x 17 paper can be used.
A. While still in the EP mode the frequency width desired for the plotted spectrum should be set. To do
this:
-Type F. The computer will respond by printing F1[PPM]= followed by the current ppm value for the
left border of the spectrum. Type the desired value (say 10.00p) followed by <rtn>. The computer will
respond with F2(PPM)= and the current right hand border value. Type the desired value (e.g. 0.00p
<rtn>).
-The height of the plotted peaks will be the same as they appear on the screen so adjust this before
plotting.
-Exit EP by typing <rtn>
B. The digital plotter has many optional features. To set these:
-Type DPO <rtn>. The computer will ask a series of questions about the plotted spectrum. If the
current answer is correct then just type <rtn>. If you wish to change the answer then type in the desired
answer followed by a return. A list of the questions, and standard answers and explanations is presented
below.
DRAW X-AXIS (Y OR N)? Y
OFFSET = -2.0 Controls the distance in cm between the spectrum and the X-axis.
MARK SEPARATION= 0.2P Controls the frequency of ticks on the X-axis. In this example a tick will
appear ever 0.2 ppm.
MARK CM = -0.2 Controls the length of each tick in cm.
DRAW Y-AXIS (Y or N)? N Controls the printing of the Y-axis.
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PEAK PICKING ON PLOT Controls the printing of ppm values for each peak, individually
(P=PPM; H=HZ; N-NO)?N. Do not set to P or H without setting the threshold for peak recognition. See
manual under MI for details.
PARAMETERS (Y OR N)? Y Controls whether a list or parameters is printed. The number and nature
of these parameters can be controlled. See the manual.
PARAMETERS INTO UPPER LEFT HAND CORNER (Y OR N) N If you answer Y peaks on left side
may be obscured by parameter list.
ROTATE (Y OR N)? N Controls the orientation of the plot on the paper. N gives a horizontal plot; Y
gives a vertical plot.
TITLE (Y OR N) Y Gives a prompt underneath > and here you type the title name of spectrum you want,
followed by a <rtn>.
C. The width of the plot in cm should be set. To do this:
- Type CX <rtn>. The current value for this parameter will be displayed. If you want to change it, type
the new value followed by <rtn>, otherwise just type <rtn>. Maximum values are 25 cm for 8 ½ x 11
paper, 40 for 11 x 17 paper.
E. To actually plot the spectrum, type PX <rtn>. This will plot the spectrum, print axis, etc. Ordinarily
this is allowed to run to completion but if the plotting must be stopped, hold down the (control) key and
type PT. Do not try to execute additional commands in the print job while printing or software
corruption will occur.
F. To plot an expanded region:
Define the region by typing F1. Enter the limits of the region as F1, F2. Set the following parameters as
desired:
X0
X position of beginning of plot in cm, relative to the lower left corner of the paper.
Y0
Y position of beginning of plot in cm.
CX
Length of X axis in cm.
10A. Changing SW and O1 for Increased Resolution
It is sometimes necessary to change the digital resolution of a spectrum to image fine detail. This
can be most simply accomplished in EP mode by putting the interesting area of a previously acquired low
resolution spectrum in the window by adjusting the A and B knobs. Be sure to consider fold over of
peaks outside the window when selecting it by avoiding having peaks just outside window. Then type
<CTRL>O. The printer will printout the new O1 frequency, SW and AQ. Change TD or SI if necessary
to get desired digital resolution or to lower AQ. Examine Hz/pt in first acquisition screen (hit esc) to
assure yourself of the desired digital resolution. Reacquire the spectrum and process. The new spectrum
will cover only the new area and will be of higher digital resolution.
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11. Integrating the Spectrum
A. To display the integral on the screen:
-Type EP <rtn>. Use the A and B knobs to display the region to be integrated To enter into the
integration subroutine type I. The integral should appear on the screen superimposed on the spectrum.
The amplitude of the integral may be changed with the + or - keys. If there is a discontinuity in the
integral it is probably because the cursor is somewhere in the observed range. Use the C Knob to move
the cursor. To correct the tilt type M. Now with the C and D knobs it should be possible to flatten the
integration line; the C Knob controls the curvature and the D Knob controls the overall slope of the
integral. After correction, type M again to memorize the correction.
It is also possible to integrate only selected portions of the spectrum to avoid solvent peaks and regions
with no peaks. First integrate the complete spectrum, and adjust curvature and slope. Set the cursor to
the beginning of the first region with the C knob. Type Z to zero the integral to the left of the cursor.
Move the cursor to the end of the first region. Type A, and the type a value for the integral to that point.
Type Z to reset the integral line to zero. Move the cursor, typing Z at the beginning and end of each
desired region.
B. When ready to print the integral onto your spectrum:
-Type S. The computer will respond with X-OFFSET= to which you should respond 0 <rtn> (unless
you want the integral displaced in the horizontal direction. The computer will respond with YOFFSET= to which you will respond with the number of centimeters above the spectrum that you want
the integral line to appear, usually 1 <rtn>. Upon typing your response, the printer should begin drawing
the integral line onto your spectrum.
Homonuclear Decoupling 1H Spectra
(This is just a rough guide, however a full explanation is located in the 1H decoupling section of the
'HOW TO' books VOLUME 1 which are located on top of the NMR console).
12. Setting the Frequency to be Irradiated
A. First you should take the normal undecoupled spectrum as described above. Once this is done you
should chose the signal to be irradiated and center the cursor on it. To do this:
-Type EP <rtn>. Move the A Knob until the peak to be irradiated is in the field of view, then move the
cursor onto it with the C and D Knobs.
B. You must now set O2, the offset value for the decoupling frequency, to the cursor frequency. To do
this:
-Type O2. The value for this parameter is displayed at the bottom of the screen. Type M. The value is
now set into memory and can be seen or checked in the acquisition parameters page.
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Type <rtn> to exit the EP subroutine.
13. Setting the Decoupler Power
A. The decoupler power (DP) must be set high enough to accomplish thorough decoupling of the
particular spin system which has been chosen, but not so high as to destroy the remainder of the
spectrum. The selection of the appropriate power level is done largely by trial and error. Two power
ranges are available, H (High 0-20 watts) and L(Low, 0-0.2 watts). The value within these ranges is set
by an attenuation number in dB units ranging from 1 to 63. Note: the higher the dB number, the lower
the decoupling power. For example, a setting of 5L results in a higher decoupling power than one of 20L.
For most applications a setting of 45L to 18L is usually suitable. To input this:
-Type DP <rtn>. The current decoupler value is displayed. Change this to an intermediate value by
typing 45L <rtn>.
14. Acquiring the Decoupled Spectrum
A.
red
The decoupling amplifier must be on. Type HD <rtn>. This may be verified by observing that the
light on "CW" and "GATED" are on, to the right of the screen.
B. Set the values of RG by typing: RGA <rtn>.
C. Acquire, transform, phase and plot the spectrum as usual. When the acquisition is finished, turn off
the decoupler power by typing: PO <rtn>.
If adjustment to the power level is required, repeat by setting lower or higher power levels until success
is achieved.
Running a 13C Spectrum with Proton Decoupling
15. Setting the Parameters
Before running C13, be sure the nucleus switch on the QNP probe is set to position 1 for 13C. For best
results, switches on the preamp module should be set as follows:
Matching 3
S2
D
C1
2.3
A. Type RJ C13.QNP<rtn> to read the appropriate parameters for the QNP probe. Type PJ
C13.QNP to read the processing parameters. Initialize the hardware interface by typing: II <rtn>
B. Set MOD=1 by typing MOD <rtn>, 1 <rtn>. This will enable composite pulse decoupling during
acquisition.
C. Type RGA <rtn> to set the receiver gain. When it has finished, set the NS to the number of transients
you desire or -1.
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16. Starting, Stopping the Acquisition
A. Start accumulation by typing: AU POWGATE.AU <rtn>. Merely typing zg will acquire data, but
will not activate the more efficient composite pulse decoupling.
B. When enough transients have accumulated, you can stop it by: CTRL H <rtn>.
17. Transforming and Plotting the Spectrum
A. To transform the FID, use the standard BC; EF <rtn>.
B. Phasing, setting the reference and plotting are carried out similar to 1H spectra. Except: the reference
value set by G in EP is set according to the 13C tables, and in DPO the Mark Separation value should be
set to be about 5-10 ppm/div.
18.
Naming and Manipulating Files
A. Any information stored on either type of disk must have a name. Acceptable names have the format:
the first four letters of the filename must be the first four letters of your last name. For example
BRUSchm for a file of a student with last name: BRUSH. The whole name may have up to eight
characters in it, and with up to a three character extension. For example BRUSCHMS.001 . Using this
method makes erasing files from the hard disk much simpler, since a wildcard can be used. It is your
responsibility to remove your old files from the D2 drive. It has limited space, crashes often, and
fills up quickly. Backup to floppies if you feel you need the spectrum later.
B. A number of commands may be used to manipulate a file. Some of these are listed below:
WJ
Writes the acquisition and processing parameters
WR
Writes the spectrum and the acquisition and processing parameters
WSH Writes the shim values
RJ
Reads the acquisition parameters
PJ
Reads the processing parameters
RE
Reads the spectrum and acquisition parameters
RSH
Reads the shim values
DEL Deletes the file
C. Any file manipulation should be of the form "COMMAND FILENAME.EXT =DEVICE"
<RETURN> where COMMAND is one of the two or three letter commands above, FILENAME.EXT is
the name of the file to be manipulated, and DEVICE is the disk to which (or from which) the file is being
sent. DEVICE options are D1 or D2 for the Hard Disks or F1 for the Floppy Disk. If no DEVICE is
specified D1 is assumed. Please store all files on either D2 or F1. D1 is saved for the NMR program
and pulse sequences.
For example, if you type:
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RJ H1 <rtn>, this will load the parameters of the file 'H1' from Hard Disk 'D1' into the computer job
memory.
RE BRUSDRP.001=F1, this will read the spectrum and its parameters of the file 'BRUSDRP.001' from
the Floppy Disk drive 'F1' into the computer job memory.
D. To see what files are present on a disk you may use the directory command, DIR=F1
(for the floppy disk) or DIR=D2 (for the Hard Disk D2)
E. The '*' symbol is a wildcard. For example typing: DIR BRUSKINE.*=D2 <rtn> will list all files
present on the disk D2 having the root name BRUSKINE regardless of the extension. Note if * is used in
the filename it replaces four characters, not the whole string as in MS-DOS. Use two * to replace all
characters.
F. Please delete only your own files. Floppy disks are freely available for personal storage. Hard disks
may also be acquired for storage of large amounts of data.
19. Rebooting the Computer
On occasion, the NMR will freeze for no apparent reason. To correct this problem the computer must be
rebooted. To do this:
1) type CTRL K <rtn>
2) Next, press the black buttons on the Aspect computer (located on the right hand side
of the NMR) in this order: STOP, CLEAR, DISK
3) The screen should then clear. The date prompt and then the time prompt will be written in green.
Either put in the correct date and time when it asks or reply with <rtn> in both cases. It will then
automatically subdivide the disk memory and load the program.
4) Type <rtn> again. It should now be at the main DISNMR program
20. Leaving the spectrometer
1) Remove your sample and insert one of the Ethylbenzene standards.
2) Lock the instrument on that sample. Shim by adjusting Z and Z2 for maximum lock level.
3) Turn off the decoupler by typing PO <rtn>.
4) Turn off the observe power by typing PR <rtn> 0 (return).
(Note that all the red lights (to the right of the screen) should be off.
5) Turn down the screen brightness using the black knob at the lower left of the screen but do not turn it
completely off.
6) Tidy up.
21. Other Useful EP Commands (Additional EP commands are available. See manual)
E
F
G
I
cycles between F1, F2 limits and a cursor value; to a scale on the screen in ppm
Enter F1(left) and F2(right) frequency limits for plot.
Set the cursor frequency. Enter value in Hz or value followed by p for ppm.
Enter integral Mode.
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M
Tilt/Curvature correction, knob C (Curvature), knob D (Tilt).
M
Memorize tilt/curvature correction
Z
Zero integral at cursor.
A
Assign integral value at cursor.
M
Set minimum value for peak picking.
O1 Set O1 to cursor value.
O2 Set O2 to cursor value.
P
Enter Phase mode.
B
Use biggest peak for reference for phasing.
C
Use cursor position for reference for phasing.
M
Memorize phase correction
5
Peak picking of currently displayed region, result to screen.
6
moves the spectrum down on the screen.
7
moves the spectrum up on the screen.
8
gives S/N at the cursor point.
9
shows individual data points on the expanded spectrum, pressing 9 again returns it.
:
(colon) changes the frequency values from Hz to ppm.
esc then H gives the EP help program.
Page 14 of 15
Bruker AM-300 Training and Operator’s Manual
Rev 1/11/02
Appendix A—Probe Tuning
Probe tuning must be matched to the sample in order to minimize pulse widths and maximize sensitivity.
Although the effects are small for routine proton spectra, they can be dramatic for more complex pulse
sequences. Although the tuning changes between different organic solvents usually do not justify the
effort to tune, if you are changing from an organic solvent to water or D2O, retuning the probe is usually
worthwhile, especially if the sample contains salts. If you are starting a long experiment, you will want
to check the probe tuning.
Disconnect the cable labeled TRANSM F1 from the side of the preamp box near the magnet, and attach
the cable directly to the probe H1 jack. Open the door on the right side of the console to gain access to
the XMIT MATCH meter. Type RJ TUNEH1.700 to load proton tune parameters. For 13C or 31P load
TUNEC13.700 or TUNEP31.700 and attach the cable to the X jack on the probe. Type ZG to start
acquisition. Adjust the SENSITIVITY knob next to the XMIT MATCH meter to show deflection of 3050% of full scale. Adjust the T and M knobs on the probe to minimize the deflection. The T and M
knobs interact strongly, and must be adjusted iteratively. After tuning stop the acquisition by typing
<CRTL>H, reconnect the TRANSM F1 cable to the preamp box, and reconnect the probe to the preamp
box.
CAUTION: Do not attempt to adjust the X channel of the QNP probe. There are four adjustments
that must be done in the proper order. Consult with the Instrumentation Specialist.
Page 15 of 15