Below is the first slice of a NOESY spectrum of codeine. The sweep width is too narrow, resulting in phase distortions due to the filters (see more detailed explanation). It is not possible to get all peaks phased correctly.
After processing, this phase "twist" causes streaks in the contour plot that can obscure peaks.
Below is the first slice of a NOESY spectrum of a different codeine sample, taken with larger sweep width. Notice that all peaks can be phased.
The resulting contour plot is free of the streaks seen above.
See also: phasing problems in noesy spectra, analysis of the noesy spectrum of codeine
Last updated: 01/22/2003
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