84 (327) BRUKER BIOSPIN User Manual Version 002
Basic Setup Procedures
The spectrum of Figure 4.26. was taken at contact power levels as set for ada-
mantane. Furthermore, a 50% ramp was used, which has a rather low average
RF level corresponding to about 5.7µsec in this case (25% less than 4.5 µsec).
This does not spin lock the protons well enough. So the power level of the contact
needs to be increased. Set spnam0 = ramp70100.100. Set sp0 and pl1 to about
2 dB less attenuation and check S/N again. Re-optimize the HH condition observ
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ing the peak at 176 ppm (which is less strongly coupled to protons and therefore
exhibits a sharper HH matching condition) in steps of 0.3 dB. In this case, S/N im
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proves to 100:1. Then optimize the decoupling pulse pcpd2 in steps of 0.2 µsec,
observing the peak at 43 ppm (which is more sensitive to decoupling mis-sets).
Here, this led to another 10% improvement in S/N.
Good Laboratory Practice requires that evaluation measurements be taken in
suitable periods. Store the optimized glycine spectrum together with the following
important information:
1. Value of field setting.
2. Name of the shim file.
3. Name of the operator.
4. Probe setup (triple mode or double mode, high range or low range setting, WB
probes only, name or part number of the probe).
5. Description of the sample (which reference rotor, weight of glycine and spin-
ner).
6. Any additional comments, for instance the reading of the micrometer setting
for the X tuning adjustment (not available on all probes).
Write this information into the title file so it is stored with the data set as well as all
other acquisition and processing parameters. Recalling this data set and acquir
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ing a new data set should give the same spectrum within +/- 10% of S/N.
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