Standard experiments

Here you will find information on possible 1-D experiments and 2-D experiments.

Measuring frequencies

A complete list of the frequencies of all nuclei with spin >0 with information on their availability in Wuppertal can be found here (pdf).
Detailed information on frequencies, standards and referencing can be found in the IUPAC recommendations (2008).

Concentrations

For all ^13C experiments, the concentrations should be as high as possible.
To avoid nonsensical ^{13C measurements}, the concentrations are checked using their ^{1H spectra}. If the signal-to-noise ratios are too low, all ^{13C experiments}are automatically cancelled on working days. Thin solutions as well as long-running special experiments should therefore mainly be submitted for weekend measurements (until Friday noon).

The referencing is automatically referenced to the respective ^{13C signal}of the deuterated solvent, provided the signal pattern is not too disturbed.

A comprehensive list of ^1Hand ^{13C shifts}of common impurities (e.g. _H2O) in various solvents can be found in Organometallics 2010, 29, 2176-2179.

Some of the standard experiments consist of combined measurement series with interdependent spectra, e.g.
^1H(PROTON) - ^13C(C13CPD) - ^13C(C13DEPT135p)
The proton spectrum determines the number of scans in the ^{13C spectrum}(256, 1024 or cancellation). The phase correction of the DEPT spectrum as well as the referencing is taken from the previous ^{13C spectrum}.

Optimisation of the SW spectral range

In the case of 1D spectra, e.g. ^19For ^{31P spectra}, an option can be set in which an overview spectrum is first recorded with a reduced scan number. Depending on the resulting spectrum quality (signal-to-noise ratio), either

(a) aborted,
(b) continued with unchanged resolution with the scan number NS increased by a factor of 4 or
(c) the spectral range (SW) optimised and the scan number NS adopted or reduced by a factor of 4 depending on the spectrum quality.

The additional experiments (spreads) are saved under the following experiment numbers (expno):
^1H+1000
^13C+2000
^19F+3000
^31P+4000
Other +5000

For ^{19F spectra} (AVANCE 400 only) there is a special spectrum sequence consisting of
(a) ^{19F overview spectrum},
(b) sweep-optimised ^{19F detail spectrum},
(c)^{1H-decoupled 19F spectrum}with parameters from (b),
(d) with the centre frequency (O1) from (b)^{19F-decoupled 1H spectrum}and
(e) normal ^{1H spectrum}.

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