Double-CP
User Manual Version 002 BRUKER BIOSPIN 263 (327)
Figure 20.6. Double CP optimization of PL5 in increments of 0.1 dB.
Note how narrow the optimum DCP conditions are. However, with diligent prepa-
ration, one should be very close to the optimum with the first try.
12. Run an experiment with 16 scans and compare the signal amplitude with the
signal intensity of the
13
C CPMAS experiment with the same number of scans,
using dual display. The intensity ratio of the aliphatic resonance of the CPMAS
compared to the one obtained with the DCP experiment gives the DCP yield,
see
Figure 20.7..
Figure 20.7. Double CP yield, measured by comparing CPMAS and DCP ampli-
tudes of the high field resonance.
Note that the C
1
carbon receives very little magnetization under these conditions,
the transfer is rather selective.