Rules for using NMR routine
http://www.biochemie.ch.tum.de/eisenreich/NMR/nmr.html
From outside find data with:
https://www.oc1.ch.tum.de/intranet/nmrWebdisk.html
14.01.2011
PD Dr. Wolfgang Eisenreich (WE, head of the NMR unit, administration, service and
maintenance, hardware and software, implementation of new experiments):
Tel.:289-13336; email: [email protected]
Christine Schwarz (CS, automation and cryo gases, measurements at special
temperatures):
Tel.: 289-13049; email: [email protected]
Birgit Keil (automation):
Tel.: 289-13043; email: [email protected]
Christoph Grassberger (cryo gases):
Tel.: 289-13359; email: [email protected]
§1 Intention
The intention of the NMR routine is to efficiently measure NMR samples co-equally for a large
number of research groups, for each coworker and member of these every research groups, and for
students participating in practical courses. The highly sensitive instrumentation should be accessible
and useable for every research groups´ users. The samples from students are measured by the
technical staff.
§ 2 Personal data, rights and responsibilities
2.1 The spectrometers have to be used very carefully following the rules.
2.2 Using the spectrometers requires the knowledge of these rules, the participation in at least one
introductory course, and the permanent supervision by the head and staff of the unit, as well as by
the NMR confidant(s) of the research groups.
2.3 There has to be at least one NMR confidant in every research group who serves as a contact
person between the users and the head/staff of the NMR unit.
2.4 The head of the NMR routine unit has the authority in all NMR affairs concerning the unit.
2.5 Due to the large number of users with different requirements, expertise, training and principles
of operation, the rules have to be obeyed strictly. In addition, each user has to work in a cooperative
and friendly style, if possible at all.
2.6 In case of continued and serious mal-operation, the rights of individual users or individual
research groups can be restricted by the head of the NMR unit.
§ 3 Contingents and fees
For the time being, there are no defined time slots, contingents or specific constrictions for individual
research groups/users. Using the service instrumentation is free of charge. However, costs due to
maintenance or repair of a specific instrument are distributed among the research groups on the
basis of the used time slots with the same instrument over the last year (under control of the
automatic accounting in ICONNMR).
§ 4 Important rules for private safety
4.1 NMR spectrometers imply strong magnetic fields including hazardous stray fields. These fields are
increased in the direct vicinity of the magnetic centers. Typically, within a radius of approximately 2-3
m from a magnet, these fields are dangerous and can destroy magnetic materials. Therefore,
patients carrying a heart pacemaker are strictly forbidden to enter the NMR rooms.
In addition, metallic tools can become dangerous “bullets” in the vicinity to the magnet and injure
humans and instrumentation. Thus, heavy metal parts like gas bombs, tools and carriages are
forbidden within the NMR room.
Magnetic cards (EC-cards, SIM-cards or similar things) are also damaged in direct vicinity to the
magnet. Therefore, they have to be laid down at the entrance (e.g. hood after the door) or at the
central corridor in the NMR room. This also holds true for loose metal parts (keys, spatula, scissors,
bridge bars, slides or similar things). Please proof the contents of your open shirt or coat pockets.
You should also lay down your mechanical clocks.
4.2 Electric radiation: Due to the electronic components in the consoles, there is significant electric
radiation if the doors of the consoles (front or back) are open. Therefore, the doors (in the front and
back) have to be closed.
4.3 Magnets and auto samplers: Potential vibrations of the magnets are suppressed by sensitive
dampers. The auto samplers are adjusted exactly and they must not be moved. Therefore, the
magnets and auto samplers must not be touched/moved when the samples are put into the sampler.
Do not lean against the magnets or auto samplers when you put the tubes into the carrousel.
4.4 Highly toxic and explosive substances are not allowed. Tubes containing toxic compounds and
organic solvents (e.g. CDCl3) have to be closed accurately. Tightly close the tube with a cap, don´t use
broken NMR tubes.
4.5 The tubes have to be smoothly fixed in the spinners (not too strongly, not too slightly!!). In case,
take another spinner. Take care not to break the thin glass of the tubes.
4.6 Using both high-field instrumentations (AV 500 and AV 500c) tubes with adequate specifications
(e.g. Wilmad or Norell tubes specified for > 400 MHz) are required.
§ 5 Spectrometers
5.1 General
The NMR routine department currently (2011) operates six NMR spectrometers (AV 500, AV 500c,
DRX 500, AV 360, AV 250, AV 200). In the medium term, another spectrometer will be integrated (AV
300) and the more than 15-years old DRX 500 has to be upgraded with a new console and probe
head.
The most important features of the mentioned spectrometers are shown in Table 1 (attachment).
Currently implemented experiments, the required amount of samples and the specific measurement
times are listed in Table 2 (attachment).
5.2 Mode of operation
5.2.1 The spectrometers AV 500, AV 360 and AV250 are operated in a full open-access mode. Each
individual user is responsible for the auto samplers´ assembly, the input of the required experiments
by ICON-NMR, the control of the measured tubes, and the processing/archiving of the data. The log-
in in ICON-NMR occurs with password-saved accounts for each research group. The supervisor sets
up new accounts on demand.
5.2.2 The NMR staff operates the spectrometers AV 500c, DRX 500 and AV 200. For measuring
samples by these spectrometers, you have to bring samples (filled tubes) to the staff.
5.2.3 The acquisition is done in full automation. This means that shimming, locking, acquiring the FID,
and data transfer (= FIDs) to a fileserver occur automatically (controlled by ICONNMR). In case of AV
500, AV 500c and AV 360, the measurements are done at 300 K. The samples are tempered in the
magnet 5 minutes before the measurement starts to equilibrate the temperature. Data analysis,
print-outs, and archiving are done by each user with external PCs (typically using MestreNova,
campus license is available for each user).
5.2.4 Sensitive samples can be measured with the priority function in ICON-NMR (normally you can
set up short experiments; if longer measurements have to be done contemporarily, you can do this in
exceptional cases, but you have to obtain approval by the staff; the measurements are then done at
reserved times).
5.2.5 The automation has to be interrupted at least once a week to supply the magnets with cooling
media (liquid nitrogen, liquid helium). Depending on the requirements, this takes about 1-2 hours
per spectrometer; currently during Thursday morning). Helium is filled at required intervals (normally
2-3 times a year). In these cases, the automation has also to be interrupted (about 2 hours).
5.2.6 In exceptional cases (e.g. for high-temperature measurements up to 80 °C, low-temperature
measurements down to 0°C, or for titration experiments), the automation has to be stopped and
measurements can be done after having consulted the staff (CS or WE). These experiments are then
done manually by CS preferably after the magnet supply with liquid nitrogen (i.e. Thursday morning).
In case, contact CS at least 3 days before. Measurements at changed temperatures can be done with
AV 360, AV 500 and AV 500c, presently.
§ 6 Sample preparation
Measurements can only be done with fully dissolved samples free of particles. No solid-state NMR!
To enable a high-quality spectrum, the following rules are important:
1. Use 5 mm quality tubes with at least 7´ length (e.g. Schott Duran Type E or Norell 5400 or better
ones for the high-field instruments). Only use intact and unscratched tubes. Before putting the tubes
in the spinner, clean the tubes with cloth free of lint. In any case, check the integrity of the tube.
Remove air bubbles (especially in D2O-samples) by careful shaking.
2. The solutions´ concentration should be adjusted according to the data given in Table 2
(attachment). If the concentration is too high, line broadening can result. If the concentration is too
low, the signal-to-noise ratio will be a disaster.
3. Heavy metal ions can cause line broadening. Avoid or remove paramagnetic ions during the
sample preparation. Consult your supervisors in case.
4. Again: The NMR solution has to be clear. Suspensions or precipitations cause disappointing quality.
Particles have to be removed by filtration or centrifugation.
5. The filling height in the tube has to be exactly 4 cm (this is equivalent to 500 – 600 μL of solvent).
The filling height influences the shim-behavior which is pre-adjusted to 4 cm height.
6. Close the NMR tubes with caps securely and densely.
7. Mark the NMR tubes carefully with a water-proof pen directly beneath the cap. This makes the
finding of your samples easier.
8. Treat the tubes with great care. Don´t scratch the tubes while carrying, storing or cleaning
(scratches cause troubles during the measurement). Don´t knock the tubes on the table or benches.
§ 7 Post-handling of samples
1. Retrieve the samples as soon as possible after the measurement. However, take care that all
experiments have been measured as requested before taking from the samples. After the
measurements, the tubes are kept in special equipments for at least 1 week. Please don´t extricate
the tubes hectically from the equipments, don´t scratch the tubes to one another or kick them on the
table (this leads to scratching or disruption).
2. NMR is a non-destructive method. For documentation, it might make sense to store critical
samples for a while (enabling repetition of the measurements with the option of additional
experiments). Consider that plastic vessels (caps) can contaminate the samples, especially with
organic solvents. If there is no archiving, dispose the compounds and solvents professionally. Don´t
clean the tubes with heavy metalliferous purifying agents (chromo sulphuric acid or something like
that). Don´t scratch the tubes while cleaning (use a soft pipe cleaner if necessary). Don´t forget to
also clean the caps. Don´t dry the tubes and caps at temperatures > 80°C.
§ 8 Setting samples and experiments
The following steps are assumed on an open ICON-NMR window. If this window is not shown,
contact the staff.
1. Log in to your account by “change user”. Choose the account and enter your password.
2. The input are listed by the number (position) in the auto sampler (holder #). Auto samplers with
120 positions have an inner circle in the carousel (1-60) and an outer circle (61-120). Don´t mix
them! Select the next available position (shown in ICON-NMR window with “available”) with double
click. The input bar opens. Enter the sample specification under “name”. Select the solvent under
“solvent”. Select the “experiment”. Set the title if necessary.
3. If you need more experiments with the same sample, open another editing bar by “add”.
4. Adjust the sample in the spinner (not too heavily, not too slightly). Adjust the height in the spinner
by the specific tool. Note that the instruments have specific adjustments. Therefore, use the tool
specified for the respective instrument. Do not touch the code of the spinners. Please note that there
are different types of spinner for different instruments. Don´t interchange.
5. Transfer the experiments with “submit” to the queue.
6. Further experiments can be set up following steps 2-5 afterwards.
7. Log out with “Change User” in “Lock ICON-NMR”.
8. Enter the measurement in the logbook (in following order: Holder #, name, sample labeling, if
applicable comments/observance).
9. From outside: Find the data under the web-disk:
https://www.oc1.ch.tum.de/intranet/nmrWebdisk.html
9. Retrieve the measured samples.
Priority:
Depending on the spectrometer and selected experiment, the measurement of sensitive samples can
be set on priority (see also § 5.2.6). Therefore put a mark in “Pri”.