Removal of zero-quantum peaks from 1D selective TOCSY and NOESY spectra

Selective 1D TOCSY and NOESY experiments are widely used for structure determination. However, they often give distorted peak shapes owing to coherence transfer though zero-quantum coherence (ZQ) which cannot be suppressed by conventional phase cycling or pulse-field gradients. This paper demonstrates that ZQ contributions can be removed from selective 1D spectra by introducing a ZQ evolution time, as previously demonstrated for 2D NOESY spectra by Wang et al. [A three-dimensional method for the separation of zero-quantum coherence and NOE in NOESY spectra, J. Magn. Reson. A 102 (1993) 116-121]. This approach is simple to implement and robust, and is not demanding of spectrometer hardware. Using a new approach to phase cycling described here, spectra can be acquired in a similar time to spectra without a ZQ evolution time.