Longitudinal two-spin order in 2D exchange spectroscopy (NOESY)

Attention is drawn to a class of signals that appear if the rotation angles of the radio-frequency pulses in the 2-dimensional (2D) exchange expt. are inadvertently or deliberately set to b!=p/2. The signals (zz signals) arise from longitudinal 2-spin order in the mixing period, and can be sepd. from genuine exchange signals by exploiting the characteristic response to a p pulse inserted in the mixing period. Pulse sequences are shown for (1) conventional 2D exchange spectroscopy, (2) a modified 2D exchange expt. for excitation and reconversion of longitudinal 2-spin order, and (3) suppression of zz signals in 2D exchange spectroscopy. The efficiency of the sepn. procedure is illustrated with NOESY spectra of the protein basic pancreatic trypsin inhibitor. [on SciFinder (R)]

Published in:
Journal of Magnetic Resonance, 59, 3, 542-50

 Record created 2006-02-22, last modified 2018-03-17

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