Please
use only intact sample tubes and check if the fit and condition of the plug are
correct.
Sample
tubes must not be longer than 21 cm and not shorter than 15 cm.
Sample
tubes should be marked in the upper quarter with the sample id identical with
the id given on the submission form (permanent marker).
Please observe the requested amount of deuterated solvent (4.5 cm,
700ul).
Please
submit your samples with a reasonable and appropriate concentration.
Your
samples should be homogeneous (no suspension, no precipitate) and diamagnetic.
Please
choose the machine which suites your requirements best.
Keep
appointments and submit samples for overnight measurements by 2:00 pm (Friday
11am)
Please
fill out the form thoroughly, completely and unambiguously. Please mention in
particular if your solvent is only partially or not deuterated
Please use only intact sample tubes and check if the
fit and condition of the plug are correct.
In
order to improve the homogeneity we have to shake the samples before starting
the measurement. In addition we cannot insure that during the handling the
sample is always in an upright position. Thus in case of a broken sample tube
your substance might get spilled.
Sample tubes must not be longer than 21 cm and not
shorter than 15 cm.
Sample
tubes which exceed a length of 21cm will be broken by the sample changer. On
the other hand, a length of 15 cm is necessary in order to be able to place the
sample in between the r.f. coils of the probe head.
Sample tubes should be marked in the upper quarter
with the sample id identical with the id given on the submission form (permanent
marker).
In
case of a wrong labelling we might not be able to return you your proper
sample. Because we are handling many samples at the same time (sample changer),
they might get mixed up.
Please observe the requested amount of deuterated
solvent (4.5 cm, 700ul)
We
have to spend a lot of time to achieve a good homogeneity of the local magnetic
field. For this reason we need a minimum amount of deuterated solvent. If your
tubes are not properly filled you might obtain broad signals or observe a
splitting of peaks. Please shake the sample thoroughly before submission. There
can be regions of different concentration in the sample spoiling the
homogeneity as well. Because only the small volume in between the r.f. coils can be observed, too much solvent only causes a
dilution of your sample.
Please submit your samples with a reasonable and appropriate
concentration.
Samples
have to be submitted with a concentration, which is suited for the required
experiment (e.g. 50 to 100 mg, 13C, medium sized compound). For the acquisition
of routine carbon 13 spectra we can’t afford more than 128 scans (10 min real
measurement time). The signal to noise ratio increases only with the square
root of the measurement time. For this reason a useful carbon 13 spectrum could
hardly be obtained after half an hour if it does not displays a clear signal
after 10 minutes. If the available amount of substance is only small you should
use only as much deuterated solvent as necessary (see above). If you can not
get a meaningful carbon 13 spectrum, we can offer you an overnight measurement.
You can switch to HMQC/HMBC spectra as well, which are much easier to obtain
(higher sensitivity).
Your samples should be homogeneous (no suspension, no
precipitate) and diamagnetic.
Not
dissolved substance, ferromagnetic and paramagnetic material can spoil your
spectra.
Please choose the machine which suites your requirements
best:
Spectrometer best suited for server partition
.
AC250 1H 13C concentrated sample only, overnight
13C nmr.chemie…. /u/data/ASPECT/nmr
ECX400 1H 13C
AMX500 13C
DEPT chemnet /a/data/ecp/nmr
(delta)
ECP500
1H 2D COSY HMQC HMBC chemnet /a/data/amx/nmr
(delta)
Data
are available in the XWINNMR format (/nmr) or Jeol
Delta format (/delta).
Spectra
obtained at different field strengths can be used in combination (e.g. HMQC, C)
If
a 13C spectrum of a certain sample has been measured already
recently at 400 MHZ, please mention the filename when submitting the sample for
a HMQC experiment.
Keep appointments and submit samples for overnight runs
until 2 pm (11 am Friday).
We
are short of measurement time. Any free time overnight may be needed by somebody
else.
Please fill out the form thoroughly, completely and
unambiguously. Please
mention in particular if your solvent is only
partially or not deuterated.
The
information about your sample is needed for carrying out the required experiment.
The knowledge of the solvent you have used is very important in particular when
working with sample changers. A trial structure of your molecule would help us
to pay attention to special carbons. The amount of material can give us an idea
how much measurement time might be needed. Please submit each sample with one form
(AC2500 at most 3 samples), otherwise they could get
mixed up. For 250 MHz spectra please give us your filename and sufficient
numbers. 400 and 500 MHz data will be saved using your name together with some
extensions. As students can not get an account on their own they will need a
signature and an account to save the data. A word document of the submission
form can be found at: /a/data/backup/Spektrenzettel.latest version.doc